I just wanted to talk about a busy week of community management and leadership related content I will be involved in in July 2013 in Portland, Oregon.

Community Leadership Summit 2013

The Community Leadership Summit is the primary annual event that brings together community leaders, organizers and managers and the projects and organizations that are interested in growing and empowering a strong community. The event pulls together the leading minds in community management, relations and online collaboration to discuss, debate and continue to refine the art of building an effective and capable community.

The Community Leadership Summit 2013 takes place at the Oregon Convention Center in Portland, Oregon on 20th – 21st July 2013, which is rather conveniently the weekend before OSCON.

At the heart of Community Leadership Summit 2013 is an open unconference-style event in which everyone who attends is welcome to lead and contribute sessions on any topic that is relevant. These sessions are very much discussion sessions: the participants can interact directly, offer thoughts and experience, and share ideas and questions. These unconference sessions are also augmented with a series of presentations from leaders in the field, panel debates and networking opportunities.

I can’t quite believe that this is the fifth anniversary of the Community Leadership Summit, and I am determined to make this the very best year yet! We already have an awesome list of pre-registered attendees, and this is shaping up to be yet another fantastic example of the primary place for community managers and leaders to get together to discuss, share, and learn best practice.

The event is completely free to attend, you just need to register first. I hope to see you there!

Community Management Training at OSCON

Speaking of OSCON, which takes place the week after the Community Leadership Summit 2013, I am also delighted to announce that I will be running my very first community management training class.

As some of you will know, I wrote The Art of Community published by O’Reilly (now in its second edition), which has rather fortunately become the best-selling book on community management and leadership.

For some time now I have wanted to deliver a training class that takes many of the concepts of the book, but extends them with detailed problem solving discussions, workshops, Q+A sessions, and more to provide an intense, detail-rich class about how to manage and lead communities, be them small and local or large and global.

On Monday 22nd July 2013, the day after the Community Management Summit 2013, I will be delivering this one day community management training class.

Topics in the class will include:

• Welcome and Introductions
  • Discussing how the class will work, student introductions, and facilities information.
• The Core Mechanics Of Community
  • Read/write communities.
  • Understanding the social dynamics.
  • Building retention and generational growth.
• Planning Your Community
  • Understanding where to focus community management.
  • Gathering stakeholder and community requirements.
• Building a Strategic Plan
  • The importance of a crisply defined strategic plan.
  • Structuring and documenting goals and objectives.
  • Delving down to the work item level.
• Building Collaborative Workflow
  • Understanding the collaborative needs of your community.
  • Building effective communication channels.
  • Determining infrastructure and tooling needs and how to resource them.
• Defining Community Governance
  • The role of governance.
  • Governance styles: dictatorship, delegated leadership, and enlightened dictatorship.
  • Assessing the governance needs for your community.
  • Building, codifying and documenting your governance structure.
  • Growing effective leadership in your community.
• Marketing, Advocacy, Promotion, and Social Media
  • Assessing marketing, advocacy and promotional needs.
  • Building a buzz cycle.
  • Using social media effectively.
  • Tracking publicity work and re-aligning for efficiency.
• Measuring Your Community
  • Knowing what to measure.
  • Defining useful growth and health metrics.
  • Understanding to how to read and react to metrics to provide more focused strategy.
• Tracking and Measuring Community Management
  • The importance of building credibility from good work.
  • Planning for different visibility needs: stakeholders, the community, and your team.
  • Tracking projects, using burndown charts, and reacting to project changes.
  • Tracking growth and decline.
  • Tracking community health and building a network

Find out more about and book your seat in the class by clicking here. Space is limited, so be sure to reserve your seat as soon as possible!

Burnout and Bickering: a Community Manager’s Guide to Conflict

I am also pleased to announce that I will be presenting a brand new presentation at OSCON on Wednesday 24th July 2013 at 2.30pm in D137.

The talk is entitled Burnout and Bickering: a Community Manager’s Guide to Conflict, and here is the description from the talk page

One of the most challenging aspects of growing community is managing conflict and burnout. While we often see the effects of conflict, getting to the heart of the issue is often more challenging.

In this new presentation from Jono Bacon, the Ubuntu Community Manager and author of The Art of Community, he presents a comprehensive guide to conflict and its many different causes.

The presentation explores how to identify these different causes (such as stress, personality differences, language/age/cultural barriers, and more), how to identify when problems are happening in a scalable manner, and how to resolve conflict in a progressive and repeatable way.

Bacon will also cover preventative measures to reduce the potential for both conflict, stress, and burnout, and wrap the content in a set of practical tools you can use in your own community.

All of this will be delivered in Bacon’s amusing anecdote and story filled style, delivering practical recommendations and techniques in a fun and contextual presentation.

I am excited about this presentation. As some of you will know, I have talked before about burnout and managing stress and conflict in communities, and this presentation provides extensive coverage of the topic. I am looking forward to presenting this at OSCON.

See more about the talk by clicking here.

As you can see, quite a week for community management and leadership! I hope to see you there!

I’ve blogged three times now, here, here and here, highlighting some of the apps being written with the Ubuntu SDK.  Well after covering 44 of them, and more already popping up since yesterday’s article, we’ve decided that we need to start getting these into the Ubuntu Touch Preview images so that people can try them out on supported devices, give the developers real-use feedback and bug reports, and generally promote the amazing work being done by our community of app developers.

The Collection

So Alan Pope (popey) and I have kicked off what we’re calling the App Collection, which are apps being developed outside of the scope of our Core Apps project, but that we still want to support, promote, and  guide through the process of getting them ready for deployment to Ubuntu devices.  This means we’re going to commit to helping developers get their apps packaged, and we’re going to be uploading them to a new PPA specifically for these apps.

The Apps

We’re starting out by collecting a list of known apps, with information about where to find their source code, the status of packaging for the app, and finally whether they are available in the PPA or not.  I seeded the list with the apps I’ve been blogging about, but it’s open to anybody who has an app, or knows about an app, to add it to this list.

Apps should be in a usable state before adding them to the list, and should perform a function that might be of interest to a user or tester.  Hello World apps are great for learning, but it’s not really something that you want to promote to users.

Packaging

You don’t have to know about Debian packaging to get your app in our PPA, we’re going to help you bootstrap and debug your package.  Our goal is to provide the minimal amount of packaging necessary for your app to be installable, on the desktop or on devices, and work properly.  Of course, if you can provide packaging for your app, that will greatly speed up the process of getting it into the PPA.

We would also welcome any help from packagers. Even if you don’t have an app of your own, you can help support the app developer community by spending some time getting their packaging in order.  QML apps are relatively simple when it comes to packaging, so a seasoned packaging veteran could probably knock one out in a matter of minutes.

PPA Review

You won’t have to conform to all of the requirements that you will to get into the Ubuntu archives, and there won’t be a lengthy review process.  The Apps Collection is offered up for users to evaluate and test Ubuntu Touch and apps written for it, there is no guarantee of stability or security.  Generally if it installs and runs, we’ll include it in the PPA.  But we’re not crazy, and we won’t be uploading apps that are obviously malware or detrimental to the user or platform.

Preview Image Review

Your app will need to go through a more intense review before being approved to go into the default install of the Ubuntu Touch Preview.  You code will be inspected by the engineers responsible for the preview images, to make sure it won’t cause any problems with stability or security that would interfere with the primary goal of the preview images, which is showing off the incredible user experience that Ubuntu provides on touch devices.

Inclusion

Once it’s ready, your app will join the default apps being developed by Canonical, as well as Core Apps being developed by other members of the community in collaboration with Canonical project managers, as part of the demonstration platform for Ubuntu Touch.

This is a great opportunity for you, as a developer, to get your app in the hands of a large number of early adopters.  It’s also a great opportunity for us, being able to promote off our platform and how it is being used by the app developer community.

The excitement around the Ubuntu SDK and application development is still going strong, both on the Ubuntu Touch Core Apps side and with independent developers. So strong, in fact, that it’s time for another round of updates and spotlights on the work being done.

Core Apps in the Touch Preview

Some big news on the Core Apps side is that they are now being reviewed for inclusion in the daily Ubuntu Touch Preview images being developed by Canonical for the Nexus family of devices, and by community porters to a growing number of others.

Now that all of the Core Apps are being regularly built and packaged in the Core Apps PPA, they can be easily installed on desktops or devices.  And, after being reviewed by the team building the Ubuntu Touch Preview images, three of them have been selected to be part of the default installed application set. So please join me in congratulating the developers who work to them.

For the Calendar, Frank Mertens, Kunal Parmar and Mario Boikov have done a fantastic job implementing the unique design interactions that were defined by Canonical’s design team.  For the Calculator, Dalius Dobravolskas, Riccardo Ferrazzo and Riccardo Padovani were able to quickly build something that is not only functional, but offers unique features that set it apart from other standard calculators.  Finally, the Clock app, where Juha Ristolainen, Nick Leppänen Larsson, Nekhelesh Ramananthan and Alessandro Pozzi have put together a visually stunning, multi-faceted application that I just can’t get enough of.

New Independent App Development

In addition to the work happening on the Core Apps, there has been a continuous development by independent app developers on their own projects.

LoadShedding

Load shedding (or rolling blackouts) are a way for electricity utilities to avoid being overloaded by energy demands at peak times.  This an be an inconvenience, to say the least, especially if you don’t know it’s coming.  Maybe that’s why developer razor created this LoadShedding schedule app.

Multi-Convert

Multi-Convert was originally an Android application, written in HTML5, that is now being ported to Ubuntu.  Multi-Convert allows real-time conversion of weight, length, area, volume and temperature between different standard units.

 TV Remotes

I ran across not one, but two different apps for the remote control of home-theater-PCs, bringing the promise of your mobile phone as a “second screen” to Ubuntu Touch.

First is Joseph Mills (who also created a Weather app featured in the first of these roundups), with a remote control for MythTV:

And if you’re an XBMC user instead, not to worry, because Michael Zanetti has you covered with his remote control for XBMC:

CatchPodder

If you use your mobile device for listening to podcasts, you’ll be pleased to find the nice and functional podcast manager CatchPodder, which lets you subscribe to multiple feeds as well as playing files directly from the server.

AudioBook Reader

Keeping with the theme of listening to people talk on your Ubuntu device, we have an AudioBook manager and player that is being written with the Ubuntu SDK, which lets you load books, display cover images, and more.

Bits

If you’re a software developer, sysadmin or network engineer, there’s a good chance you’ve had to convert numbers between decimal, hexadecimal and binary.  This makes Bits a very handy utility app to keep in your pocket.

Periodic Table

From the same developer who created a Software Center front-end and Pivotal Tracker (both featured in previous posts) has a new project underway, an element browser that gives you loads of detailed information about everything on the periodic table.

WebMap

Canonical engineering Manager Pat McGowan has gotten into the fun too, building an app for displaying web-based maps from a number of providers.

GetMeWheels

For Car2Go customers looking to rent or return a vehicle, GetMeWheels lets you easily find the nearest locations to you.  Created by the same developer as the XBMC remote, this app was originally developed for Maemo/Meego, but is now being ported to the Ubuntu SDK.

PlayMee

A third app from the developer of GetMeWheels and XBMC Remote is PlayMee, a local music player that again was originally developed for Maemo/Meego, and is being ported to the Ubuntu SDK.

Tic-Tac-Toe

Tic-Tac-Toe is not a fancy game, but this one developed by Hairo Carela makes beautiful use of animation and colors, and even keeps a nice score history.

LightOff

If games are you thing, you should also check out LightOff, a simple yet challenging game where the object is to turn off all of the lights, but clicking one toggles the state of every square around it.

That’s all for now, keep those apps coming and be sure to post them in the Ubuntu App Developers community on Google+

I think that most asked question about Chromebook in last months was about hardware acceleration. So let’s write something about it.

OpenGL ES

There is a driver for OpenGL ES for Samsung Exynos5 Dual cpu present in Chromebook. But there are two versions of it: Week35 and Week45. Both require different kernel versions.

Ubuntu 13.04 has 3.4.0-5 kernel package which was built from R23 kernel branch. Week35 OpenGL ES driver works with it and you have to grab it from ChromeOS (but maybe it got updated there already).

I still have to find time and get R25 (or R26 or R27) kernel working so we could upgrade to Week45 driver. This one is available in ChromeOS as well (beta or dev).

Where are my packages?

There were packages which provided OpenGL ES driver binaries (week45). I removed them due to license issues as it looks like Samsung bought Mali T604 license from ARM Ltd. and got it working with Exynos5 Dual. Then they sub licensed it to Google for use with ChromeOS.

So Samsung does not distribute the driver — Google does. And even when they give tarball with files there is no license in it — just standard “Google Terms of Service” note.

No redistribution license == no packages. Sure, someone can make “chromebook-opengles-driver-installer” like package which would grab binaries from ChromeOS (I did such for week35) or will fetch them from network. Feel free to do it — you can use my chromebook-mali-driver repository as a base. Once you will get it working I can put it into Samsung Chromebook PPA.

Multimedia decoding

Other thing is hardware accelerated multimedia decoding (maybe also encoding). Under ChromeOS it was done with OpenMAX stuff. Google even had some binaries available but they crashed badly under Ubuntu.

How situation looks today? No idea as I did not had time for Chromebook stuff in last months.

All rights reserved © Marcin Juszkiewicz
Hardware acceleration on Chromebook was originally posted on Marcin Juszkiewicz website

If you just want to play the game, here’s where you find it. Or, in a terminal window write:

sudo add-apt-repository ppa:diwic/theblobgame
sudo apt-get update
sudo apt-get install theblobgame

Then just search for “blob” in the Dash.

The rest of this blog post is mostly directed towards game developers.

Background and motivation

Ten years ago I finished a game called “The Blob Game”. It was a 2D platform style game, more cute than violent. My cousin had made the graphics, a level editor, and part of the game engine. I made seven levels, music, and completed the code. Back then, I was still working for a company doing closed source software for Windows, so naturally this game was a Windows game.

A while ago I decided to try to port this game to Ubuntu. My main motivations were:

• To see how easy (or hard) it was, given my current level of experience. Also because we currently have some undergoing efforts to make Ubuntu a better gaming platform, and what better way to do that, than to become a game developer yourself?
• People complain that there are not enough games available in Ubuntu – I wanted to make my small contribution to help even that out.
• Nostalgia purposes – after all, most of the work with the game was to make the levels and the artwork, rather than actual code. All of this can be reused, and it would be nice if this game could entertain a new audience.

Overall, the experience has been good. Sure, there has been some work to do and new things to learn and conquer, but there has been very little of frustration. A fun side project!

One of the strength and weaknesses of the Linux ecosystem is all the choices you can, and have to, make. What components do you choose to build your software on? That can be bewildering, especially if you’re new to Linux and unfamiliar what components are suboptimal for one reason or another. I would therefore like to talk you through the choices I made and why I made them. As usual, these are my own opinions, not my employer’s.

Language: C

To give some background, my cousin and I started programming twenty years ago. Back then, my father introduced me to Turbo Pascal, which was more powerful than the QBasic that came with DOS 5.0. Ten years later, I was using Delphi (the Windows continuation of Pascal) at my work. So the game was written in Delphi, mixed with some hand written assembly code (!).

Was it possible to reuse the code written? I looked at the available compilers:

• GNU Pascal. This project seems mostly abandoned, so not a stable choice for the future.
• FreePascal. This was the main alternative, but it has its own code generator (not integrated with GCC or LLVM), so chances are it won’t keep up in the future. Also, if you need to link to a library, chances are you have to translate headers yourself.

So; rewrite the code. In what language? My choice fell on C, for the following reasons:

• It is a very popular language, maybe even the most popular one. It is likely to be around for a long time, and have support for new processors and architectures as they come to market.
• It is compatible with everything. In fact, it’s what every other language tries to be compatible with (Java has JNI, Python has C extensions, etc).
• It is what I use at work, so I know the language very well. (Both Linux and PulseAudio are written in C.)
• I like the low memory footprint and predictability of C – you want a game to run fluently, the audio to run at a reasonably low latency, and so on. With the exception of calling functions you don’t know about, you can almost see how quick your code executes. I’m not sure how well Java, Python, and the other garbage collecting languages do in this area; so my fear might be unfounded, but at least I know C does well.

Gaming library: libSDL

Fortunately, the cross-platform toolkit libSDL is very well supported under Linux. I have almost only positive experiences of this library: it seems very stable. It handles graphics (window setup, fullscreen etc), input events (keyboard, mouse, gamepads just work), audio, and more. The documentation is extensive and there are plenty of examples out there. And because libSDL is already used by so many games already, most distributions make sure libSDL works on their software and hardware.

What about OpenGL? Well, this is a 2D game, so I don’t need 3D. It is possible I could use some hardware acceleration for the scaling (the frame is rendered in 320×200, then upscaled to the screen’s resolution), but my very simple scaler seems to perform well enough. As such, there was no real need to bring in a dependency on OpenGL.

Music library: FluidSynth

First I’m a more than a bit biased on this dependency, as I’m one of the FluidSynth developers. However, the reason I first got involved with FluidSynth was that I wanted to use it in a game, and needed to fix something in the library…

FluidSynth is a softsynth – it takes MIDI data and a soundfont, and gives you rendered audio as a result. This has the drawback that you need to download a soundfont too, and the only one available in the Ubuntu archive is > 100 MB. The good thing is that FluidSynth is very embeddable into many different kinds of applications, so taking the audio output, mixing it with sound effects, and then send it to the sound card (with libSDL) was easy. It is also easy to manipulate the MIDI in real-time – in this game I’ve used it to pitch down the audio when you die.

GUI toolkit library: glib and GTK3

Let’s first admit it; in the Linux world we don’t have anything as stable as the Win32 API for creating windows. The two main contesters, GTK and QT, are both rewritten every five years or so. So if I, ten years from now, need to run this game again, chances are that I have to rewrite this part. The GUI is just used in the beginning though (to setup the game), so it shouldn’t be too much work.

I chose GTK over QT here because

• I had previous experience with GTK
• QT adds complexities to your build system, as you need not only a C++ compiler, but also a special preprocessor to turn some special QT constructs into valid C++ code.

Build system: simple Makefile

In my case, my application takes a few seconds to compile. For really simple applications like this one, I find build systems such as autotools or CMake to be more trouble than what they solve. In both cases, you’ll have to learn an additional language just to specify your build dependencies. (Autotools also has a few nuisances, such as requiring some extra files to be present, and in all upper-case, such as AUTHORS or NEWS.)

For larger projects, they make more sense though as they might help you create libraries for different platforms, give nice error messages when build dependencies can not be found, etc.

Licensing: LGPL-2 + CC-BY-SA

This is always a tricky and controversial subject, and I’d like to reiterate that this a layman’s thoughts on the topic and nothing else.

• GPL is the strongest license when it comes to free software. But that also makes it a very incompatible license, it is essentially impossible to link GPL code with everything that’s not extremely weak (e g BSD) or explicitly made to fit with GPL (e g LGPL). One example of an incompatible license is MPL 1.1 – this was a quite popular license in the Delphi community, and the incompatibility with GPL was a real pain.
• It is not obvious where the boundaries between GPL and non-GPL code can be, causing confusion in court from time to time. FSF might offer some advice on how to interpret the license; but they’re not a neutral party. In this case, I find the LGPL, the second strongest license, more clear.
• So LGPL-2, LGPL-3 or LGPL2+? Well, to me, any “at your option, any later version” clause is out of the question; for me, that’s essentially the same as giving your code away to the FSF as they can relicense your code any way they wish. And LGPL-2 is shorter than LGPL-3 because LGPL-3 includes the full GPL-3 license code, too.
• LGPL-2 is suitable for code, but not for data. So music, graphics and levels are licensed under CC-BY-SA. I was considering adding “non-commercial”; but the border between commercial and non-commercial can be fluid, and might also be a problem with the DFSG, so I skipped that part.

Update: Seems I didn’t read closely enough – LGPL-2 has a GPL-2+ clause, now making it possible for the FSF to relicense my code by making a new GPL version.

I also downloaded new sound effects (which is the only part not completely made by myself or my cousin), to make sure there was no licensing problems with those.

Getting it into the Ubuntu Software Center

Unfortunately, this does not currently work for free applications. While adapting my packaging to fit the requirements was relatively straight-forward, and also walking through the dialogs for app submission, when all this work was done, I was met by the following message:
Thank you for submitting a gratis Free Software application through MyApps. At this time we are unable to process this request, as we are working on the implementation of a new app upload process.
Bummer.

A packaging tip

While we’re on the topic of packaging, let me just share a quick tip. If you’re new to Debian packaging (the system used in Ubuntu), and just want to package your own app, one thing to think about is that the packaging system was designed for having coders and packagers belong to separate organisations. So that means, that if you during packaging find a bug in your code, you’re meant to make a temporary patch, send that the coder, who will then make another release of the non-packaged software, which you will then package. In practice, this is a bit heavy-weight if you’re just one person and don’t keep packaging and code apart, so I used the following shortcut:
tar -cjf theblobgame_0.20130202.orig.tar.bz2 --exclude=debian theblobgame-0.20130202
If you fixed something in the code and want to work on the packaging, the command above will create a new “code release” from the packaging system’s point of view.

…and finally, it’s free software!

This means you’re allowed not only download and run this game, but also look at the code, copy-paste parts into your own game (under the terms of the LGPL-2!) or just use for inspiration. You can fix a bug or a feature and send me patches (or publish the modified code yourself), etc. Enjoy!

Update: Someone asked me how to get the source, so here’s a quick howto:
If you have executed the lines in the top of this blog post, just change into a suitable directory and execute “apt-get source theblobgame”. Before you build, you can use “sudo apt-get build-dep theblobgame” to automatically install all build dependencies. Building can be done with “dpkg-buildpackage -b” (from the source code directory). Then install the resulting .deb package (“sudo dpkg -i theblobgame_version.deb”) to test.

If you’re not running Ubuntu/Debian, you can get the source from going to the PPA page, click “View package details”, click one of the arrows on the left side in the table, and download the file ending with “orig.tar.bz2″.

Disclaimer: This does not mean that the source is written by the book, with lots of helpful comments, etc. The game engine is mostly a quick translation of the code as it looked like ten years ago, with new glue code added for interfacing with the libraries I now depend on.

Hurray, it’s Friday!  I’ve got a somewhat lighter article to celebrate the end of the work week (sorry to those of you for whom it isn’t).  Today I’m going to cover revision 7, in which I replaced the large default Headers with small, customized headers specifically for my app.  If you haven’t read my previous articles in this series, I strongly encourage you to do so, as each one builds on top of the one before it.

New Header Component

To replace the old Header, I first had to create the new ones.  Headers are relatively simple things, they sit on top and display text, so there wasn’t a whole lot to it.  I created an Item to act as the container.  Items are the most based UI elements in QML, all they really do is hold other elements, and provide the base type for other elements to inherit from.  Inside of the Item I put a Rectangle, which is pretty much exactly what it sounds like.  What a Rectangle can do that an Item can’t is set a border and background color, which is what I wanted to do with my header.  Finally I put a Label inside of the Rectangle to contain the header.

Item {
    id: header
    anchors.right: parent.right
    anchors.left: parent.left
    anchors.top:parent.top

    height: headerText.height + units.gu(1)
    Rectangle{
        anchors.fill: parent
        color: 'lightblue'
        border.width: 1
        border.color: 'grey'
        Label {
            id: headerText
            anchors.centerIn: parent
            text: ''
            fontSize: 'large'
            font.bold: true
        }
    }
}

You can see that I set the anchors for the Item to place it at the top of it’s parent (SubredditListView in this case) which is important for reasons you’ll see below.  I also set the Rectangle’s background color to ‘lightblue’. For the subreddit page I made the fontSize large, bold, and centered in the header (that’s what anchors.centerIn: parent does).  That works for the short text name of a Subreddit, but for the article I needed something a little bit different.

Item {
    id: header
    anchors.right: parent.right
    anchors.left: parent.left
    anchors.top:parent.top
    visible: false
    height: headerText.contentHeight + units.gu(1)
    Rectangle{
        anchors.fill: parent
        color: 'lightblue'
        border.width: 1
        border.color: 'grey'
        Label {
            id: headerText
            anchors.fill: parent
            anchors.verticalCenter: parent.verticalCenter
            anchors.margins: units.gu(0.5)
            font.bold: false
            wrapMode: Text.WrapAtWordBoundaryOrAnywhere
        }
    }
}

Here I made left the Label text it’s default size, and not bold.  I also didn’t center it horizontally like I did for the subreddit page.  But most importantly, I set the text to wrap so that articles with an overly long title will flow over multiple lines, increasing the size of the header to accommodate it.

Keeping it up to date

Since I was already passing the full article data data to the ArticleView component, extracting the new title and updating it was easy to do, I just needed to add a line to the onArticleChanged callback.

    onArticleChanged: {
        if (article) {
            articleWebView.url = article.data.url
            headerText.text = article.data.title
        }
    }

But changing the header on the SubredditListView required a little more work.  Since I already had a property on it called subreddit, I was able to write an onSubredditChanged callback to run whenever I needed to update the Subreddit name in this header.

    onSubredditChanged: updateHeader()
    Component.onCompleted: updateHeader()
    function updateHeader() {
        if (subreddit == '') {
            headerText.text = 'Frontpage'
        } else {
            headerText.text = subreddit
        }
    }

Next time: Transitions

One of the really neat things about QML is that it makes developing rich, fancy interfaces very easy.  And part of how it does this is by building support for transition animations right in at the ground level.  I knew from the beginning of this project that I wanted to try them out, and in the next revision I finally took the opportunity to add them.

Well I’m back again, with part 4 of this series.  No, that’s not a typo in the title, this post will be primarily about revision 5 and revision 6 of my bzr branch.  What happened to rev 4?  Well it was pretty boring to be honest, just removing some console.log() calls that I used as a poor excuse for a debugger.  Anyway, boring.

If you haven’t read the previous articles in this series, you’ll want to do that before reading any further here:

• Rev 1: Creating a project, ListViews & ListModels
• Rev 2: ListItem thumbnails, Dialogs and WebKit
• Rev 3: Refactoring, visual improvements & gesture controls

Comments

Everybody knows that comments are half the fun of Reddit, but up until now uReadIt wasn’t able to view them.  Now, the proper way to do this would be to use the Reddit API to download the comment threads, and load them using nested ListViews.  But that’s going to take a while, and I wanted comments now.  So I cheated, took the easy way out, and just used the existing WebView to load the Reddit comments page URL instead.  I’ll do it the right way in a later revision….probably.

The first thing I needed was a way to load comments instead of the article content.  This meant finally using the Comments toolbar action I put in place earlier.  But I needed a way to change back too, nobody likes a one-way trip, so I added an Article action as well.

    Action {
        id: commentAction
        objectName: "comment"
        visible: true

        iconSource: Qt.resolvedUrl("comments.png")
        text: i18n.tr("Comments")

        onTriggered: {
            articleContent.showComments()
            articleAction.enabled = true
            commentAction.enabled = false
            articleViewActions.active = false
        }
    }
    Action {
        id: articleAction
        objectName: "article"
        enabled: false

        iconSource: Qt.resolvedUrl("avatar.png")
        text: i18n.tr("Article")

        onTriggered: {
            articleContent.showArticle()
            commentAction.enabled = true
            articleAction.enabled = false
            articleViewActions.active = false
        }
    }

Then I had to write the showComments and showArticle functions, which would switch the WebView.url from one to the other.  There was just one problem, that code didn’t have the comments url, only the content url.  So first I had to pass more data to my articleView page.  To avoid having to do this again, I decided to just pass it the whole article data model that I was getting from JSONListModel, that way I would have all the data I could potentially need for future features.

Since I created a new property called article, I also get a callback handler called onArticleChanged, which I took advantage of to determine if an article’s content was already a link to a Reddit comment page, and if so disabling the option to switch between Article and Comments.

Page {
    id: articleView
    title: 'Article'
    property var article: undefined

    onArticleChanged: {
        if (article) {
            articleContent.article = article
            commentAction.enabled = !article.data.is_self
            articleAction.enabled = false
            articleView.title = article.data.title
            articleContent.visible = true
        }
    }

Now I could finally implement showComments and showArticle, which I decided to do inside of ArticleView.  To support that, I would also need to pass the article data model on again, this time to ArticleView.  Then I could use that data to switch the WebView’s url.

Item {
    property var article: undefined
    property string baseUrl: 'http://www.reddit.com'

    onArticleChanged: {
        if (article) {
            articleWebView.url = article.data.url
        }
    }
    ...
    function showComments() {
        console.log('Comments: '+baseUrl + article.data.permalink)
        articleWebView.url = baseUrl + article.data.permalink
    }
    function showArticle() {
        articleWebView.url = article.data.url
    }

Subreddit Filters

I usually only read the Hot subreddit filter, I’ve only used New a handful of times, but like I said in the first article in this series, I’m going things to learn the Ubuntu SDK, not make a Reddit app.  I wanted to write some code that used the Ubuntu Popups.Popover component, and changing Reddit filters seemed like a good use for that kind of component.

Like Popups.Dialog, using a Popover is relatively simple.  You start with a Component to contain your popup, add your components to it, then call PopupUtils.open.  For changing filters, I chose to just put in a Column filled with ListItem.Standard items, one for each filter.  When one of them is selected, it will change a new filter property on my SubredditListView (which will reload from Reddit using the new filter).

Component {
    id: popoverComponent
    Popups.Popover {
        id: popover
        Column {
            id: containerLayout
            ...
            ListItem.Standard {
                text: "Hot"
                selected: articleList.filter == 'hot'
                onClicked: {
                    articleList.filter = 'hot'
                    PopupUtils.close(popover)
                }
            }
            ListItem.Standard {
                text: "New"
                selected: articleList.filter == 'new'
                onClicked: {
                    articleList.filter = 'new'
                    PopupUtils.close(popover)
                }
            }
            ListItem.Standard {
                text: "Rising"
                selected: articleList.filter == 'rising'
                onClicked: {
                    articleList.filter = 'rising'
                    PopupUtils.close(popover)
                }
            }
            ListItem.Standard {
                text: "Controversial"
                selected: articleList.filter == 'controversial'
                onClicked: {
                    articleList.filter = 'controversial'
                    PopupUtils.close(popover)
                }
            }
            ListItem.Standard {
                text: "Top"
                selected: articleList.filter == 'top'
                onClicked: {
                    articleList.filter = 'top'
                    PopupUtils.close(popover)
                }
            }
        }
    }
}
tools: ToolbarActions {
    ...
    Action {
        id: filterAction
        objectName: "filterAction"

        iconSource: Qt.resolvedUrl("settings.png")
        text: i18n.tr("Filter")

        onTriggered: {
            PopupUtils.open(popoverComponent, filterAction.itemHint)
        }
    }
}

Packaging

Finally I was ready to package uReadIt, to make it easy to install.  I copied my packaging files from what was used by the Ubuntu Touch Core Apps, which was itself copied from packaging files used by the notepad-qml app.  Now I’ll admit, it’s not perfect, and we’ve already had patches submitted to fix the Core Apps packaging, changes which I will be applying to uReadIt at some point.  So don’t take these as the right way to package your app, I’m putting them here to explain in a broad sense what the different files do in a Debian package.

debian/control

The control file gives all of the data about your package.  It has two sections, the first is for the source package, it contains the source package name, list of dependent packages needed to build your app and package, and some other miscellaneous information used by the packaging system.  Below that will be one or more binary package definitions.  I only have one, you probably will too.  This section contains another list of dependent packages, but these are packages needed to run your app, not build it. It also contains a space to describe your application.  The first line of the Description should be a brief description, used when listing a lot of packages together, and the lines below it should have a longer description, used when showing more information about a single package.

Source: ureadit
Priority: extra
Maintainer: Michael Hall 
Build-Depends: debhelper (>= 8.0.0), 
Standards-Version: 3.9.4
Section: misc
Homepage: https://launchpad.net/~mhall119/

Package: ureadit
Section: misc
Architecture: any
Depends: ${shlibs:Depends}, ${misc:Depends},
         qmlscene,
         qtdeclarative5-ubuntu-ui-toolkit-plugin | qt-components-ubuntu,
         qtdeclarative5-qtquick2-plugin
Description: Reddit Browser
 Desktop application for browsing Reddit, it's articles and comments

debian/rules

The rules file is what actually does the building, it’s like a Makefile for your package.  Ideally this doesn’t do much more than calling dh (debhelper).  In fact, mine should be doing that, but it has a lot of unnecessary complication due to being copied from one project to another to another.  You’re probably better of just ignoring mine, just remember that debian/rules does the building.

#!/usr/bin/make -f
# -*- makefile -*-
# Sample debian/rules that uses debhelper.
# This file was originally written by Joey Hess and Craig Small.
# As a special exception, when this file is copied by dh-make into a
# dh-make output file, you may use that output file without restriction.
# This special exception was added by Craig Small in version 0.37 of dh-make.

# Uncomment this to turn on verbose mode.
#export DH_VERBOSE=1

# Work-around for some machines where INSTALL_ROOT is not set properly by
# dh_auto_install
override_dh_auto_install:
	dh_auto_install -- INSTALL_ROOT=$(CURDIR)/debian/tmp

# Workaround a bug in that debhelper package version
override_dh_install:
	mkdir -p $(CURDIR)/debian/tmp/usr/share/applications/
	mkdir -p $(CURDIR)/debian/tmp/usr/bin/
	mkdir -p $(CURDIR)/debian/tmp/usr/share/uReadIt/
	cp uReadIt.desktop $(CURDIR)/debian/tmp/usr/share/applications/
	cp uReadIt.bin $(CURDIR)/debian/tmp/usr/bin/uReadIt
	cp -r *.qml *.js *.png $(CURDIR)/debian/tmp/usr/share/uReadIt/
	
	dh_install --sourcedir=debian/tmp --fail-missing

%:
	dh $@

debian/changelog

The changelog file contains a record of revisions to your package, just like a bzr or git changelog.  More importantly, the changelog is what tells debhelper the lasted version of your package.  So the (0.3) in the top line on mine tells it to build ureadit_0.3_all.deb.  It will also use the signature line to try and find a matching GPG key when signing packages.

ureadit (0.3) raring; urgency=low

  * Initial release

 -- Michael Hall   Mon, 25 March 2013 23:09:00 -0400

debian/copyright

Making sure that FOSS packages can be distributed, modified, and redistributed is important, so in Debian and Ubuntu having a properly formed copyright file is a requirement.  I won’t go into much detail on how to do this, the link at the top will take you to the official spec.  The key pieces are the sections that give a file glob, license and attribution.  You can have as many of these sections as you need to properly cover all of your app.

Format: http://dep.debian.net/deps/dep5
Upstream-Name: uReadIt
Source:

Files: *
Copyright: 2013 Michael Hall
License: GPL-3.0

Files: debian/*
Copyright: 2013 Michael Hall
License: LGPL-3.0

Next time: Customizing headers

The stock Ubuntu component Headers are nice, but they weren’t serving my purposes.  I wanted them to display more text, and ideally take up less room.  So in the next revision, I replaced them with some custom components that did exactly what I wanted.

Paul Wise poked me this morning about uploading fatrace (“file access trace”, see the original announcement for details) to Debian, thanks for the reminder!

So I filed an Intent To Package, and will upload it in a few days, unless some discussion evolves.

I also took the opportunity to do some modernization: The power-usage-report script now uses the current PowerTop 2.x instead of the old 1.13, uses Python 3 now, and includes the “process device activity” in the report. I released this as 0.5. The actual fatrace binary didn’t change its behaviour, it just got some code optimizations; thanks to Yann Droneaud for those.

This is part 3 of an ongoing series, you should read rev 1 and rev 2 first.

In this revision I make several visual improvements to the existing components, try out some new gesture-based interactions, and undergo a significant refactoring effort to separate my code into smaller, cleaner files.

The Refactor

For the refactor, I wanted to split my app into logical components, based largely on the QML Components, but grouping the major and minor components that could be treated as a single entity.

I started by separating the components for each of my Pages, subreddits and articleView, into independent QML files that I could treat as single components when adding them to my Page.  For the SubredditListView, I further separated the model code (based on the JSONListModel) and delegate code (based on ListItem.Subtitled) into their own files.

These changes would allow me build domain-specific functionality on top of the base components in the Ubuntu SDK, while keeping my main code file uncluttered by all of that code.  My main file, uReadIt.qml, could then focus solely on layout and navigation.

Connecting the dots

I went out of my way to avoid inter-dependency between these components, so the ArticleListItem doesn’t need to know about the ArticleView.  But I wanted to change my ArticleView whenever an ArticleListItem was clicked.  This meant I had provide aliases, signals and callback handlers on my top-level components, and they connect them together in my main file.

I gave my SubredditListView an itemClicked signal, which would automatically provide an onItemClicked callback property that I could access from uReadIt.qml.  Then, in my delegate’s onClicked callback, I simply fired off the signal with a reference to the ListModel item.

Item {
    ...
    signal itemClicked(var model)
    ...
    ListView {
        id: articleList
        ...
        delegate: ArticleListItem {
            id: articleItemDelegate
            onClicked: {
                itemClicked(model)
            }
        }
        ...
    }
    ...
}

Then in my ArticleView code, I made a property alias called url that was linked to the url property on the inner WebView component.  Setting ArticleView.url would then behave exactly like setting WebView.url did.

Item {
    property alias url: articleWebView.url
    ...
    WebView {
        id: articleWebView
        url: ""
        ...
    }
    ...
}

Finally, in uReadIt.qml, I set the onItemClicked handler for my SubredditListView to change the url property on my ArticleView,

    PageStack {
        id: pageStack
        ...
        Page {
            id: subreddits
            ...
            SubredditListView {
                id: articleList
                ...
                onItemClicked: {
                    articleView.title = model.data.title
                    articleContent.url = model.data.url
                    articleContent.visible = true
                    pageStack.push(articleView)
                }
            }
            ...
        }
        Page {
            id: articleView
            title: 'Article'

            ArticleView {
                id: articleContent
                ...
            }
        }
        ...
    }
}

Visual tweaks

Alright, enough of the refactoring, I managed to do some more interesting and fun things in this revision as well.  For one thing, I improved the look of thumbnails on the ListView by giving different icons for in-Reddit articles, as well as NSFW and ‘default’ articles.  I also restricted their size to 5×5 grid units.

A Grid Unit is a resolution-independent way of defining size of things in the Ubuntu SDK.  Instead of using pixels, which don’t work on both high and low density displays, or using physical units which don’t work on both hand-held and 10-foot displays, the Ubuntu SDK uses a Grid Unit.  The number of pixels in a grid unit depends on the device your app is running on.  On high-density displays, like the Retina displays on new Macs, your grid unit will use more pixels than on a standard resolution LCD, so that a Grid Unit is roughly the same physical size on both.  Likewise, on a television screen meant to be viewed from across the room, a grid unity will have a larger physical size than it would when running on a hand-held device, even if they are both 1080p screens.

ListItem.Subtitled {
    text: model.data.title
    subText: '('+model.data.domain+') - ' + model.data.score + ' - ' + model.data.subreddit + ' - ' + model.data.author
    icon: {
        var icon = model.data.thumbnail;
        if (icon == 'self') {
            icon = Qt.resolvedUrl("reddit.png");
        } else if (icon == 'default') {
            icon = Qt.resolvedUrl("avatar.png");
        } else if (icon == 'nsfw') {
            icon = Qt.resolvedUrl("settings.png");
        }

        return icon;
    }
    __iconHeight: units.gu(5)
    __iconWidth: units.gu(5)
    progression: true
}

In addition to these changes to the ListView, I was also getting tired of wondering if my content was being slow to load, or if it had failed for some reason, so I wanted to add a loading progress bar to my ArticleView.

To do this, I used the ProgressBar component from the Ubuntu SDK, and connected it to the loading property for the WebView component.  First I set the visibility of the progress bar to the loading status of the content with the onLoadingChanged callback.  If it was loading, the bar was visible, and when it wasn’t the bar was hidden.  Next I used the onLoadProgressChanged to set the progress bar’s value to the current loading progress of the content.  Once everything was connected, QML made it all just work.

    WebView {
        id: articleWebView
        ...
        onLoadingChanged: {
            loadProgressBar.visible = loading
        }

        onLoadProgressChanged: {
            loadProgressBar.value = loadProgress
        }
    }
    ProgressBar {
        id: loadProgressBar
        ...
        minimumValue: 0
        maximumValue: 100
    }

Dragging gestures

Finally I started to experiment with drag-gestures for moving from one page of results to the next, or reloading the subreddit entirely.  This was pretty tricky, the ListView component doesn’t provide any single property to tell you how far past the either end a user drag or flick has moved the content.  However, it does provide a contentY property that I could use to, eventually, calculate how far off the natural bounds the user has moved the content.

First I created a callback handler for onContentYChanged so that my app was aware of the content movement within the ListView.  Then, if Qt says the user was dragging the content (as opposed to movement caused by a flick), I would calculate the over-drag for both the top and bottom of the list.  I didn’t want to trigger an event for small drag distances, so below a certain threshold it will give instructions to continue dragging to perform an action, and beyond that threshold the text will change to tell the user to let go of the drag to initiate that action.

Next time: Packaging

By now I had an app that I wanted to use regularly on my Nexus 7.  Previously I had been running it from QtCreator by pressing Ctrl+F12 while I had my N7 connected via a USB cable, but that meant I could only start it when I was plugged into my laptop.  Not ideal for in-bed Reddit browsing.  So in the 4th revision of my code branch I added Debian packaging files for easy installation.

Read the next article

In my previous article I discussed how I got started with a new Ubuntu SDK app, and how easy it was to get a listing of Reddit articles displayed in a simple list. In my second revision, I added image thumbnails to that list, the ability to change to a different subreddit, and finally the capability to actually display the article’s content.

Thumbnails

For some subreddits, Reddit will provide an image thumbnail to go along with the article.  Not only is this a nice feature of Reddit, but it’s also supplied as part of their API.  Since ListItem.Subtitled derives from ListItem.Base, it also has an optional icon property that can conveniently take a URL.  This made adding the thumbnail to my ListView incredibly easy.

Since not all articles have a thumbnail image, for now I just used a placeholder (the avatar image you get from the template).  I also didn’t do anything to make sure the images would fit in the ListItem.  In later revisions I would get a little smarter about how I handled thumbnails.

ListView {
    id: articleList
    ...
    delegate: ListItem.Subtitled {
        ...
        icon: (model.data.thumbnail) ? model.data.thumbnail : Qt.resolvedUrl("avatar.png")
        ...
    }
}

Changing Subreddits

Now that the subreddit article list in a pretty good state, I turned my attention to being able to change from one subreddit to another.  Revision 1 had a text input and button for this, but due to my not understanding QML layout this was hidden behind the header in those earlier screenshots.

So this time I decided to use another Ubuntu SDK component, Popups.Dialog, to show the form as an overlay on top of the article list.  This was very simple to do, and it looks so much nicer and more professional too.  The default theme that you get with the Ubuntu SDK makes it easy to make good looking apps, even if you’re not a designer.

The Dialog itself is straight forward, you simply wrap it up in a Component (you’ll see why later), give it a title and a bit of descriptive text for the user, and add your widgets to it.  All I needed was a TextField and a Button.  Since the Reddit “Frontpage” doesn’t have a subreddit, I decided to use no subreddit value to mean “Frontpage”, and used the TextField’s placeholderText property to display that when the TextField was empty (and yes I called it “Homepage” at first, I did correct it in later revisions).

    Component {
         id: dialogComponent
         Popups.Dialog {
             id: dialog
             title: "Change Subreddit"
             text: "Select a new Subreddit"

             TextField {
                 id: subreddit
                 placeholderText: 'Homepage'
                 text: currentSubreddit
             }
             Button {
                 id: 'goButton'
                 text: 'Go'
                 color: 'green'
                 onClicked: {
                     currentSubreddit = subreddit.text
                     PopupUtils.close(dialog)
                 }
             }
         }
    }

To call up the dialog, I added a new button to the bottom toolbar.  Since I hadn’t added any before (the “Back” button was provided by PageStack) I had to give my subreddits page a property called tools that contains a ToolbarActions instance.  Inside of that, I was able to add an Action for opening my dialog.  Here is why you needed to wrap your Dialog in a Component, because it’s the component that you need to pass to PopupUtils.open.

    tools: ToolbarActions {
        Action {
            id: subredditAction
            objectName: "action"

            iconSource: Qt.resolvedUrl("avatar.png")
            text: i18n.tr("Subreddit")

            onTriggered: {
                PopupUtils.open(dialogComponent, subredditAction.itemHint)
            }
        }
    }

Viewing Articles

Now that I could change subreddits, and my subreddit article list was starting to look pretty good, I really, Really wanted to be able to view the contents of those articles.  Since I had no idea what the contents would be (webpage, image, video, reddit comments page), I wanted to be able to display anything that could be posted to Reddit, which essentially means I needed a browser.

Fortunately, the popular and powerful WebKit browser engine has a Qt component, which makes adding it to a QML dead simple.  So in my articleView page, I just needed to add the WebView component. I did have to set the visible property to false, otherwise it would display the content of the WebView, even when the articleView page wasn’t (I suspect it has something to do with WebKit taking over rendering from Qt/QML).

Page {
    id: articleView
    title: 'Article'

    WebView {
        id: articleContent
        anchors.fill: parent
        url: ""
        scale: 1
        visible: false
    }
}

And then in the ListItem.onClicked callback handler I defined earlier, in addition to pushing the articleView page on to the top of the PageStack, I also had to set the url property of the WebView. I also set the title of the articleView page to be the article’s title. Finally, I have this callback set the visibility to true to that it would actually be displayed.

ListView {
    id: articleList
    ...
    delegate: ListItem.Subtitled {
        ...
        onClicked: {
            articleView.title = model.data.title
            articleContent.url = model.data.url
            articleContent.visible = true
            pageStack.push(articleView)
        }
    }
}

Property Change handlers

One important bit of code that changed in this revision was the addition of a global currentSubreddit property (you can see it being used in the change subreddit dialog). In QML, any property you define will automatically get an on<Property>Changed callback. This means that I got an onCurrentSubredditChanged callback (camel case, which means the first letter of your property name is capitalized), so I used that to make the appropriate changes to the other components in my app.

    property string currentSubreddit: ''
    function onCurrentSubredditChanged() {
        console.debug('Changing Subreddit: '+currentSubreddit)
        if (currentSubreddit != '') {
            subredditFeed.source = "http://www.reddit.com/hot.json"
            subreddits.title = 'Homepage'
        } else {
            subredditFeed.source = "http://www.reddit.com/r/"+currentSubreddit+"/hot.json"
            subreddits.title = '/r/'+currentSubreddit
        }

        pageStack.clear()
        pageStack.push(subreddits)
    }

Another consequence of getting these automatic property change callbacks, is that you usually just need to change a component’s property in order to get it to do something. In this case, changing the source property on my JSONListModel was enough to make it load the new Reddit API data, which was then enough for my ListView to drop it’s currently items and add the new ones just loaded into the model. It really does border on magical sometimes.

Next time: Refactoring

Up until this point, all of the code I’ve been writing was in a single uReadIt.qml file, and it was starting to get rather large. But with QML it doesn’t need to be that way (and really, it shouldn’t be that way), so for revision 3 I decided to split it out into separate files.

Read the next article

It’s official, UDS 13.05 is coming up next month, marking our second online Ubuntu Developer Summit, and coming only two months after the last one. While going virtual was part of our transition to make Ubuntu’s development more open and inclusive, the other side of that coin was to start holding them more often. The first we put into affect in March, and the second is coming in May. Read below for information about this UDS, and changes that have been made in response to feedback from the last one.

Scheduling

The dates for UDS 13.05 are May 14, 15 and 16, from 1400 UTC to 2000 UTC.  We will once again have 5 tracks: App Development, Community, Client, Server & Cloud and Foundations.  The track leads for these will be:

• App Development: Alan Pope, David Planella & Michael Hall
• Community: Daniel Holbach, Nick Skaggs & Jono Bacon
• Client: Jason Warner & Sebastien Bacher
• Server & Cloud: Dave Walker & Antonio Rosales
• Foundations: Steve Langasek

Track leads will be in charge of approving Blueprints and getting them on the schedule.  If you are going to be responsible for running a session, please get with the track lead to make sure they have marked you as being required for that session. If you would like to get a session added for this UDS, you can do so either through registering a Blueprint or proposing a meeting through Summit itself.  Both approaches will require the approval of a Track Lead, so make sure you discuss it with them ahead of time.

Changes to…

Using feedback from attendees of the March UDS, we will be implementing a number of changes for UDS 13.05 to improve the experience.

Hangouts

Google+ Hangouts have a limit of 15 active participants (if started with a Canonical user account, it’s 10 if you don’t have a Google Apps domain), but in practice we rarely had that many people join in the last UDS.  This time around we’re going to encourage more people to join the video, especially community participants, so please check your webcams and microphones ahead of time to be ready.  If you want to join, just ask one of the session leaders on IRC for the hangout URL. We are also investigating ways to embed the IRC conversations in the Hangout window, to make it easier for those on the video to keep track of the conversation happening there.

The Plenaries

Most people agreed that the mid-day plenaries didn’t work as well online as they do in person.  There was also a desire to have a mid-day break to allow people to eat, stretch, or hold a sidebar conversation with somebody.  So we are replacing the mid-day plenaries with a “lunch” slot, giving you an hour break to do whatever you need to do. We will be keeping the introductory plenary on the morning of the first day, because that helps set the tone, goals and information needed for the rest of the week.  In addition to that, we have added back a closing plenary at the end of the last day, where track leads will be able to give a summary of the discussions and decisions made.

The Schedule

In addition to the above plenary changes, we have added an extra day to this UDS, making it 3 days instead of two.  The last day will allow for overflow of sessions that couldn’t fit into 2 days, or the scheduling of follow-up session when it is determined they are necessary following a discussion earlier in the week.

Registration

Registration to attend will now be done in Summit itself, rather than through a Launchpad Sprint.  So if you’re not a track lead, and you’re not registering Blueprints, there’s nothing you need to do on Launchpad itself.  This will help those who do not have a Launchpad profile, though you will still need an Ubuntu SSO account to log in.

To register for UDS 13.04, go to the summit page, and just above the schedule you will see an orange “Register in Summit” button.  If you don’t see that, you either need to log in to  summit or you’ve already registered.

Summit Scheduler

Chris Johnston and Adnane Belmadiaf have been working hard to improve the Summit Scheduler website, taking feedback from attendees to improve the interface and workflow of the site.  We will include as many enhancements as possible before the start of UDS 13.05.  If you are interested in helping improve it, and you have some web development skills, please find them on #ubuntu-website on Freenode to find out how you can get involved.

We are pleased to announce that Canonical has stood up official mirrors in HP Cloud's AZ-1, 2, and 3 regions.

If you are using Ubuntu Server 12.10 Cloud Images, there is no action to take; 12.10 images are by default configured to use the new mirror address.

For Ubuntu 12.04 instances, the default Ubuntu image does not automatically use the in-HP Cloud mirrors. We are currently working with HP to publish a new image that defaults to the local mirrors. If you would like to switch to the new in-HP mirrors, simply run:
          
    $ sudo sed -i -e \
            's,^archive.ubuntu.com/ubuntu,nova.clouds.archive.ubuntu.com/ubuntu,g'  \
             /etc/apt/sources.list 

    $ sudo apt-get -y update

Note: *.clouds.archive.ubuntu.com is configured using split-horizon DNS. This means that the DNS answer to queries is based on the askering IP address; only queries originating within HP Cloud are answered with the HP Cloud mirror addresses. If your DNS resolver[s] is not based in HP Cloud, then you will be unable to benefit from these new mirrors. 
 

This is going to be the first in a series of articles about my journey into the wonderful world of Ubuntu SDK app development.  I’m no stranger to programming, or even app development on Ubuntu, but I am a stranger to Qt and QML.  Or at least I was.

Why build a Reddit client?

I started uReadIt for two primary reasons:

1. I missed browsing Reddit in bed from my Nexus 7 (/r/science/ is nice when the “educational” channels in the US are playing crap), which I could do when it was running Android.  But even more importantly…
2. I wanted to learn to write apps using the new Ubuntu SDK, and I always learn best by building something real.

The first of these was remarkably easy, I has a way of browsing my favorite subreddits within a day.  It’s the second reason, now, that is driving this development.  That’s important to remember, because it means I may choose to add features so that I can learn a part of the SDK, not necessarily because it’s an overly useful feature.  It also means I probably won’t be adding features that would make for an awesome Reddit app, unless they provide a way for me to try something new.

Tabs or PageStack?  That is the question

The Ubuntu SDK uses QtCreator, and adds plugins for integration with Ubuntu Devices, the Ubuntu Components, and also a set of Ubuntu App templates.  The QML templates both use the Ubuntu MainView component as it’s top-level element, but where they immediately differ is on the second-level components used for managing multiple “pages” in your app.

The first option is Tabs, which allows the user to switch between pages using an Ubuntu-themed tab-bar at the top.  This is what the Core Apps are using, and also what is used by default apps included in the Ubuntu Touch devices images, such as the Phone and Gallery apps.  Tabs are an easy way to provide flat navigation that the user can switch between any time.

The second option uses the PageStack component, which as the name implies manages a stack of pages.  PageStack doesn’t give you automatic navigation like Tabs do, you have to write the code to push pages to the stack (such as onClicked event handlers on a ListView itemm more on that later).  But it will automatically put a “Back” toolbar button in the bottom toolbar for you when when you push more than one page onto the stack, and clicking that will bring the user to the previous page in the stack.

I started out with Tabs, but decided that PageStack made more sense for what I wanted.

Putting it all together

So, to get started I created a new project in QtCreator, using the Ubuntu UI – Simple template (this is the PageStack one).  This gave me MainView, PageStack, and a single Page components in my uReadIt.qml file.  I knew I wanted the first page to be my subreddit list of articles, so I gave it an id of “subreddits”.  Next I created a second page and called it “articleView”, which is where I would load the actual article.  I gave each page a title, which the PageStack and MainView components automatically used to produce a large text header for my app.

MainView {
    // objectName for functional testing purposes (autopilot-qt5)
    objectName: "mainView"
    applicationName: "uReadIt"
    id: window

    width: units.gu(50)
    height: units.gu(75)

    PageStack {
        id: pageStack
        anchors.fill: parent
        Component.onCompleted: pageStack.push(subreddits)

        Page {
            id: subreddits
            anchors.fill: parent
            title: 'uReadIt'
        }

        Page {
            id: articleView
            title: 'Article'
        }
    }
}

Next I added a ListView component to the first page, which I knew I needed for my list of articles.  Getting data into a ListView is simply a matter of giving it a ListModel instance.  And while Qt provides a very feature-full XMLListModel, Reddit’s API uses JSON.  Fortunately there JSONListModel implementation readily available on the internet, and I quickly found one on GitHub by Romain Pokrzywka that fit the bill nicely.  All I needed to do was give it the Reddit API URL for a subreddit, a json path query for pulling out just the article data, and it was ready to go.

Page {
    id: subreddits
    anchors.fill: parent
    title: 'uReadIt'

    ListView {
        id: articleList
        ...
        JSON.JSONListModel {
            id: subredditFeed
            source: "http://www.reddit.com/r/Ubuntu/hot.json"

            query: "$.data.children[*]"
        }
        model: subredditFeed.model

    }
}

To display the JSON data in the ListView, I needed to give it a “delegate” component, which QML will use as a kind of template for building an component item for each data item in the ListModel.  I opted for the ListItem.Subtitled provided by the Ubuntu SDK Components, which would allow me to give the article title as the primary text, and the article’s Reddit score as a sub-text. By settings progression to true, it even added an indicator arrow to inform the user that clicking on it will take them somewhere else. Finally I set the item’s onClicked callback handler to push the articleView page to the top of the PageStack, which will switch the user to that page, and provide a “Back” toolbar button to return the user to the subreddits page.

    ListView {
        id: articleList
        ...
        delegate: ListItem.Subtitled {
            text: model.data.title
            subText: 'Score: ' + model.data.score
            progression: true
            onClicked: pageStack.push(articleView)
        }
    }

That’s all I needed!  QML even took care of kicking off the HTTP request to the Reddit API as soon as the app starts.  My previous GUI programming experience is with python/Gtk and Java/Swing, which are both very verbose, very explicit toolkits.  QML is almost magical, by comparison, and it did take me a while to adjust and become comfortable with it “just working” the way it should, without me having to tell it.

Next Time: Content!

With that, I committed revision 1 to my Bazaar branch.  I had a working article list being pulled from Reddit.  In my next post, I’ll be covering how I got it to display the actual content of the article in the articleView page.

Read the next article

I was trying to explain how our team did workflow to a former colleague last week and I so I started thinking about all the different workflows I’ve dealt with in my career. This one is by far my favorite, although I know it’s not git which everyone loves, I’m curious what workflows other groups use with launchpad. Take a look at this one and let me know, can our team do anything better, can yours?

First a brief note about our team at Canonical. We work on “premium” customer-facing projects, typically on ARM based hardware. We are downstream from Ubuntu for the most part, and although we do send fixes upstream when it makes sense, often we make customizations to packages that cannot go upstream. I’ll use a real-world example for this workflow explanation, we have a platform where we want to remove the user list, help menu entry, and the logout menu enty from the session indicator, so we needed to modify indicator-session to do so.

The tl;dr version of our workflow is Decentralized with shared mainline, with parts of Decentralized with automatic gatekeeper added.

Setup a Shared Master (mainline)

Grab the source for indicator-session for the distroseries we’re based on, precise in this case. We usually grab it from launchpad or apt-get source if launchpad’s precise copy is out of date. This code gets pushed to lp:~project-team/project/indicator-session. This is now the master/mainline version. Everyone on the team has write access to this, provided they follow team rules.

Setting Up My Local Branch

I have a pbuilder already setup for our project usually, so my first step is to setup my local tree. I like to use a two level hierarchy here so that builds don’t “pollute” my main project area where I have dozens of different branches checked out. So I setup a subdirectory and checkout a copy to master.

cd ~/Projects/project-precise-amd64
mkdir indicator-session
cd indicator-session
bzr branch lp:~project-team/project/indicator-session master

Now I branch master, if this wasn’t a fresh checkout, I would bzr pull in master first.

bzr branch master remove-buttons

Make Changes

At this point we make fixes or whatever changes are needed. The package is built, changes are tested, and lintian is run (this one gets forgotten many times).

We have a few goals to meet for changes, we don’t always succeed, but here they are:

1. No new lintian errors, if it’s a new package that we made, 0 is better.
2. If the package has unit tests, add a new test case to cover what we just fixed/changed.
3. Patches should have minimal DEP3 headers.
4. Coding style should follow upstream.
5. No new compiler warnings without explanation.
6. Good changelog entries with bug numbers if applicable. Entries should list what files were modified. Distroseries set to UNRELEASED still (more on why later).

A note on lintian, Jenkins is capable of rejecting packages with lintian errors. We have this disabled because we need to fix the errors that crept in first when we didn’t follow this rule.

Push to a Remote Branch for Review

We code review everything we do, so the next step is to make the branch public for a review.

bzr commit -m "good message, usually we just use the changelog entry" --fixes lp:BUGNUM
bzr push lp:~project-team/project/indicator-session-remove-buttons

Setup a Code Review

Everything is reviewed and all reviews are sent to the team, though the onus is on the submitter to ping appropriate people if they don’t get a timely review. For code reviews, everyone is expected to provide a good explanation of what they’re doing and what testing was done.

We also have one of the “enhancements” here as we have a Jenkins instance (similar to this one) setup for some projects and Jenkins gets to “vote” on the review. Packages that fail to build or fail unit tests are marked as “Rejected” in the review by Jenkins.

Merge Back to Master

After the review is approved, the code submitter merges the code and commits it up to the mainline. I’m paranoid about master changing, although the push will fail if it did, so I always update it first.

We have to also fix the distroseries back. We do this on our team because it reduces the chance that someone will dput a package that is built from a local or non-master branch. If somone were to try and dput the changes file built from the remove-buttons branch, it would fail. We really want the archive to only have packages built from master, it’s more repeatable and easier to track changes.

cd ~/Projects/project-precise-amd64/indicator-session
cd master
bzr pull
bzr merge ../remove-buttons
dch -e (modify distroseries from UNRELEASED to precise)
debcommit -r
bzr push :parent

Jenkins Does dput

Our team is slowly moving into the world of Jenkins and build/test automation, so we have Jenkins watching the master branch for interesting projects and it will manage the dput for us. This also provides a final round of build testing before we dput.

Some teams have autolanding setup, that is when the review is approved, the Jenkins instance will do the merge. For now, we’ve kept a human in the loop.

Update the Bug

It is annoying to look at a bug 3 months after you fixed it and wonder what version it’s fixed in. Although the debian/changelog tracks this, we generally always add a bug comment saying when a bug was fixed. For the most part people usually just paste the relevant changelog entry into the bug and make sure it’s marked as Fix Committed.

Shortly after announcing the Ubuntu Phone, we made an ambitious and frankly unprecedented decision to make the development of the phone’s core apps a community initiative.  We weren’t just open sourcing the apps being developed by Canonical (though we did that too), we would let the community drive the design and development of what would become the foundation of the Ubuntu Touch app ecosystem.  And we would do it ten short months.

Work Item Tracking

Building 11 apps in less than a year is a lot of work, and tracking that work is itself a lot of work.  To do this, we are using the same tools and process as the rest of Ubuntu’s development.  This means using Launchpad for code hosting and bug tracking.  But more importantly, it also means using Blueprints for planning, breaking the work into individual tasks, and assigning those tasks to individual contributors.  This also allows us to use the Ubuntu Status Tracker to view the progress being made on those tasks.  As of right now, that chart looks like this:

As you can see, when we started tracking them we had about 165 work items defined, and about 140 left to finish.  As tasks are completed, and the developer updates the Blueprint with the new status of the work item, the orange part of the chart will shrink, and the green part will grow.  If we can keep the green part on or below the black line, then we’re on track to finish them all by our October goal.

Milestones

Ten months is a short amount of time to build a collection of well designed and polished apps, but it’s also a very long time for planning development work.  In order to narrow our focus and concentrate on immediate development tasks, we’ve further broken down the development period into a number of milestones, one for every month between now and October.

So instead of planning out the entire cycle, we will be scheduling tasks on a monthly basis.  This will make the amount of work seem less daunting, and also give us a more agile cycle of planning, development, and evaluation.  Each milestones will in turn get it’s own burn-down chart, so we can track the progress being made within the month as well.

Development Teams

Work items are also separated by team, which allows us to track the progress of individual projects, as well as the overall projects of the core apps campaign.

This allows teams to easily check if they are on track to complete their project  by October, and also gives them an idea of how much (or how little) work remains to be done.

Next Steps

The first milestone, coreapps-13.10-month-0 is coming up in mid-April.  For this milestone, we have been scheduling work items that were already making good progress, or that were small enough they could be completed in the two weeks between when it was defined and when it ends.

The milestone after that, ubuntu-13.10-month-1, ends mid-May, and will be our target for an alpha-level release of most of the apps.  As you can see, there is still a lot of work to be done between now and then, but we are currently below the burn-down line, so as long as we keep the momentum going we will make that goal.

Everything not currently scheduled for one of these two milestones is targeted to the final October goal.  Sometime in May we will begin scheduling work items for the coreapps-13.10-month-2 milestone, based on the progress made on these first two miles.

PostgreSQL just released security updates. 9.1 (as found in Debian testing and unstable and Ubuntu 11.10 and later) is affected by a critical remote vulnerability which potentially allows anyone who can access the TCP port (without credentials) to corrupt local files. If your PostgreSQL database exposes the TCP port to any potentially untrusted location, please shut down your servers and update now!

PostgreSQL 8.4 for Debian stable (squeeze) and Ubuntu 8.04 LTS and 10.04 LTS also got an update, but these are much less urgent.

Debian and Ubuntu advisories for all stable releases, as well as Debian testing are going out as we speak. The updates are already on security.debian.org and security.ubuntu.com.

I also uploaded updates for Debian unstable (8.4, 9.1, and 9.2 in experimental) and the Ubuntu backports PPA, but it will take a bit for these to build as we don’t have embargoed staging builds for those. Christoph updated the apt.postgresql.org repository as well.

Warning: If you use the current Ubuntu raring Beta-2 candidate images, you will still have the old version. So if you do anything serious with those installations, please make sure to upgrade immediately.

Update: Debian and Ubuntu security announcements have been sent out, and all packages in the backports PPA are built.

Please see the official FAQ if you want to know some more details about the nature of the vulnerabilities.

This year I spent Easter in other way than in past years. Instead of staying with the family I went for demoscene party — Revision 2013 in Saarbrücken.

Please note (RSS readers mostly) that this post will contain many YouTube videos embedded. Please go to my blog to have them properly displayed (I use WordPress + Jetpack plugin to embed them).

Friday

Took us 12 hours to get there (mostly due to waiting on TXL and FRA airports) but we managed to be at party place around 19:00 on Friday. Registered, met friends and went to Kirchberg Hotel to drop bags.

Hotel has two stars but was perfectly fine for such trip as our. Clean bed, good breakfast, quiet place (except church bells at 10:00 on Sunday). All just ~2km from E-Werk where Revision took place.

Back to party, more people to meet, discuss a bit with guys from ARM Ltd about Samsung Chromebook, Cortex-A15, Mali etc. One guy joined with his Chromebook and recognized me when I asked “may I fry your speakers?” :D

Timetable listed one interesting thing: “Curio’s 2012 Essentials” which was ~1 hour long set of PC demos from previous year. It was nice as I was totally out of PC scene so was able to check how it looks.

Taxi to hotel was just 6€ ;D

Saturday

Attended “How to start writing compilers without a Ph.D” seminar as it sounded interesting to me. And it was ;) Video below:

Also had discussion with ARM guys about presenting not only technical demos (like Unreal Engine one) but also to show some demoscene productions. Soon “Beginnings” by Elude started on one of Nexus 10 tablets and was working nice. But coder who wrote it was not so happy about that when we discussed that later… I think that it would be a good thing for ARM Mali team to get some good demoscene groups to write demos for Android platform to amaze people with nice looking productions. ARM even had seminar for OpenGLES 3.0 API:

But Saturday was also full of competitions. Tracked music, oldskool music (read: 8-bit mostly), photo, animation/video, game, ascii/ansi, Amiga intros, PC 4K intros, Oldskool demos (8-bit, Atari STE, Amiga 500)…

There were many entries in compos where productions from long time no see groups/people were presented. For example in oldskool demo we got “RINK A DINK REDUX” from Lemon which was astonishing:

There were also demos for Amstrad CPC, MSX1, ZX Spectrum, Commodore 64 and other platforms. Oldskool music compo had even NES entry ;)

But it was also visible that demoscene is not full of amateurs like it was years ago. Some of videos in animation/video compo had professional level. “Lübeck 24x7x365″ took 50 days of recording but was really nice:

There was a concert in the evening… Ear plugs were not strong enough for me so I spent most of time outside talking with people. Next time need to take some better hearing protectors…

Sunday

As Saturday ended really late for us and competitions were planned for 13:00 we decided to not rush and stay in bed longer :) But at around 10:00 bells in local church started their music compo so we were not able to sleep anymore.

We got music, graphics, wild and of course PC 64K intro, web browser demo/intro, Amiga demo and PC demo competitions that day.

Graphics one was won by “Double Trouble by the Royal Forces” made by forcer & prince. Huge amount of details which was not so visible on big screen as it was on a tunnel’s wall where it was hanging as few square meters photo copy.

Wild compo… Man, that was something great. From productions made for Arduino (with some shields) though ARM Cortex-M3 one to interesting hack by Dexter/Abyss which shown one view on monochrome TV and second on oscilloscope while both were connected to Composite video signal only… See it for yourself (or grab separate entries from scene.org FTP server):

Then DJ set by h0ffman (skipped by me) and clue of party — Amiga and PC demos/intros. Different quality but most of them was really good — both from technical or design view (but not always from both at same time).

But as I am not a coder I looked mostly at design and audio/video part. All those names like ‘ray matching’ etc meant nothing to me so when someone tried to explain why demo which I did not like was so great I just told similar thing ;D

Monday

Wake up, breakfast, pack, pay, go to party place. We did not manage to get there before voting ended so not voted for PC demo compo entries. Greeted those who was still present, discussed a bit and then return trip… This time just ~9 hours but next time (if there will be such) we plan to go there by car. Less time needed.

Random stuff

I liked how party was organized — it was my first such event abroad and many people told me that Revision is the last demoscene party in old style. I really liked it. Saw many different platforms like MSX1, MSX2, C= VIC20, Amstrad CPC or Videoton…

Due to Easter time shops where closed on Sunday/Monday but it was not a problem for me as there was free coffee/tea, beer/water/orange juice was available to buy at low price (2.5€ for 0.5l beer) and there was hot food served all time (like 10:00 – midnight) also not so expensive.

Weather could be better as it was cold but at least there was no snow (which we still have here).

It was also nice to see Kiero at work as he was finishing “Machinist” Amiga demo on his x86-64 laptop with WinUAE running fullscreen. I was surprised that ASUS UL30A is capable to run it fast enough.

Amount of discussions with people is probably uncountable. Chromebook, ARM, Android, Amiga, scene were just subset of topics…

Will I go there next year? Will see…

All rights reserved © Marcin Juszkiewicz
Revision 2013 was originally posted on Marcin Juszkiewicz website

Last year I worked on a project where I was playing around with system-wide default settings and locks and I thought I’d share a post based on some of my notes. Most all of what I will mention here is covered in depth by the dconf SysAdmin guide, so if you plan on using this, please read that guide as well.

For most everyone, you have just one dconf database per user. It is a binary blob and it’s stored in ~/.config/dconf/user. Anytime you change a setting, this file gets updated. For system administrators who may want to set a company-wide default value, a new dconf database must be created.

Create a Profile

The first step in setting up other databases is to create a dconf profile file. By default you don’t need one since the system uses the default database, user.db, but to setup other databases you will. So create a file called /etc/dconf/profile/user and add the list of databases that you want. Note that this list is a hierarchy and that the user database should always be on top.

For this example, I will create a company database and a division database. The hierarchy implies that we will have company-wide settings, perhaps a wallpaper, settings on top that are specific to the division, perhaps the IP of a proxy server that’s geographically specific, and each user will have customized settings on top of that.

To create a profile, we’ll do the following:

mkdir -p /etc/dconf/profile

and edit /etc/dconf/profile/user, then add:

user-db:user
system-db:division
system-db:company

Keyfiles

(Note: I am doing this on a relatively clean precise install using a user that has not changed their wallpaper setting, that is important later)

Once you have created the profile hierarchy, you need to create keyfiles that set the values for each database. For this example, we will just set specific wallpaper files for each hierarchy. This is done with key files:

mkdir -p /etc/dconf/db/division.d/

and edit /etc/dconf/db/division.d/division.key, add the following:

[org/gnome/desktop/background]
picture-uri='file:///usr/share/backgrounds/Flocking_by_noombox.jpg'

Next we’ll create the company key file:

sudo mkdir -p /etc/dconf/db/company.d/

and edit /etc/dconf/db/company.d/company.key, add the following:

[org/gnome/desktop/background]
picture-uri='file:///usr/share/backgrounds/Murales_by_Jan_Bencini.jpg'

Finally, you need to run sudo dconf update so that dconf sees these changes.

After running dconf update, you will see two changes. The first and most obvious change is that the background is now a bunch of Flocking birds, not the Precise default. The second change is that you will see two new binary dconf database files in /etc/dconf/db, one called company and one called division. If you don’t see these changes then you did something wrong, go back and check the steps.

Since I have no default set the division’s default takes precedence

The current user and any new users will inherit the Division default wallpaper, Flocking. However, the user still may change the wallpaper to anything they want, and if they change it, that change will be set in the user database, which takes precedence. So this method gives us a soft-default, a default until otherwise modified. If you are trying this test on a user who has already modified the wallpaper, you will notice that it didn’t change due to this precedence.

If we want to force all users, new and existing, to get a specific wallpaper, we need to use a lock.

Locks

For this example, let’s assume that the IS department for our division really really likes the Flocking picture and doesn’t want anyone to change it. In order to force this, we need to set a lock. A lock is simple to make, it just specifies the name of the key that is locked. A locked key takes precedence over all other set keys.

Before doing this, I will use the wallpaper picker and select a new wallpaper, this will take precedence, until the lock is created. I picked Bloom for my test.

I like flowers more than birds.

Now it’s time to make the lock, because the IS department really doesn’t like flowers, so we create the lock as follows.

sudo mkdir -p /etc/dconf/db/division.d/locks/

and then edit /etc/dconf/db/division.d/locks/division.lock (note file name doesn’t really matter) and add the following line:

/org/gnome/desktop/background/picture-uri

After saving the file, run sudo dconf-update. Once doing so, I’m again looking at birds, even though I modified it in my user database to point to Bloom.

Lock file forces me to use the Division settings

One interesting thing to note, any changes the user is making are still being set in their dconf user db, but the lock is overriding what is being seen from outside dconf. So if I change the wallpaper to London Eye in the wallpaper picker and then remove the lock by simply doing sudo rm division.lock && sudo dconf update, I immediately get the London Eye. So it’s important to keep this in mind, the user db is being written into, but the lock is in effect masking the user db value when the setting is read back.

London Eye wallpaper is shown after I remove the lock

Lock Hierarchy

Lock hierarchy is interesting, in that the lowermost lock takes precedence. What this means is that if we lock both the company and division wallpapers, we will see the company one. In the example below I set locks on the wallpaper key for both databases, and I end up seeing Murales, the company default.

Company setting takes precedence with both locked

Locks Without Keys

It is also possible to set a lock on a hierarchy without a corresponding default key. In this instance the system default is used and the user is unable to change the setting. For this example, I set a company lock but removed the company key. The resulting wallpaper is the system default.

System default wallpaper for Precise is seen

What Value is Seen – A Quiz

If you’d like to test your knowledge of what key will take precedence when read from dconf, follow the quiz below, answers are at the bottom. For each scenario, see if you can figure out what wallpaper the user will see, assume the same database hierarchy as used in the example.

1. User Wallpaper: unset, Division Wallpaper: Flock, Company Wallpaper: Murales
2. User Wallpaper: London Eye, Division Wallpaper: Flock, Company Wallpaper: Murales
3. User Wallpaper: London Eye, Division Wallpaper: Flock, Company Wallpaper: Murales, Lock file for Company Wallpaper setting
4. User Wallpaper: London Eye, Division Wallpaper: Flock, Company Wallpaper: Murales, Lock file for Division and Company Wallpaper setting
5. User Wallpaper: London Eye, Division Wallpaper: Flock, Company Wallpaper: unset, Lock file for Division and Company Wallpaper setting

Answers: Flock, London Eye, Murales, Murales, Default for Precise

Testing

Some notes about testing this if you are trying it:

• Creating new users and logging in as them is a good way to see what settings are shown, the wallpaper is a great visual test as it’s easy to verify.
• Do not do this on your development box. I screwed up my settings right before I was going to give a demo. I’d recommend a VM. If you do screw something up, check .xsession-errors, that’s where my problem was apparent.

Summary

If you’re a system administrator or you really like pictures of birds, dconf keyfiles and locks are the correct mechanism to make settings that are defaults, soft or hard. Hopefully this has been illustrative on how they work. I’d recommend playing with them in a VM and once you understand the hierarchies and locking, they should be pretty easy to use.

We have a number of super interesting hangouts lined up and some others are planned for the next time. For now I’d like to announce we’ll have these two coming up this week:

• 2013-04-02 14:00 UTC – Thomas Voß and Keving Gunn will talk about Mir and the next iteration of Unity. What’s happening and how to get involved.
• 2013-04-04 15:00 UTC – Didier Roche will talk about auto-landing and auto-testing Unity, Ubuntu Touch Core apps and other Desktop bits.

Both hangouts are going to happen on http://ubuntuonair.com – simply go to the page, use the chat window below the video to connect and ask questions and enjoy the show. Make sure you bring your friends and questions.

Want to talk about your project/team? Demo something?

We are always looking for Ubuntu developers who want to show something, talk about their project or team or anything else. No matter if you’re a new developer and want to tell us how you got involved or if you want to show something new and interesting you found out, please let us know and we’ll make time for you.

If you missed it, I posted an earlier round of SDK apps a couple weeks ago.  Well the pace of new app development didn’t slow down, so here I am again with another round of apps being written with what is still an alpha version of the Ubuntu SDK.

Core Apps Update

First an update on the Ubuntu Touch Core Apps project.  I highlighted a few of these already in my last post, but in the past week those apps have received several updates, and others have had the initial features start to land as well.

Calculator

In addition to being able to scroll back through previous calculations, the Calculator App developers have now added the ability to start a new calculation by dragging up and “tearing off” the current one, moving it into the history for later browsing.

Clock

The Clock app has been given a slight visual update on the main screen, and all new stop watch functionality too!

Calendar

The Calendar App now shows events for the day, and will take over the full screen to let you easily view your busy schedule.

Weather

The weather app too has added some visual features, and with the detailed design workflows just released, you can expect to see major changes coming to this app soon.

RSS Reader

The RSS Reader got off to a good start this week, allowing you to add feeds and read articles, either all aggregated together or one feed at a time.

File Manager

Finally, the File Manager is now working enough to let you browse through files and folders, and even open files in the appropriate application

Independent Apps

A man of many talents

Developer Ashley Johnson has been working on a couple of new apps using the Ubuntu SDK.  His first was a touch-friendly version of the Ubuntu Software Center:

Click for video

Followed up earlier this week with an Ubuntu Touch client for the Pivotal Tracker project management web service:

Click for video

Ubuntu Loves Reddit

We must, because there is not one, not two, but three separate Reddit apps being written with the Ubuntu SDK.

By Victor Thompson

By Bram Geelen

By yours truly

Ultimate Time Waster

Even Canonical’s VP of Engineering, Rick Spencer, has gotten in on the fun.  Though his app, which gathers funny pictures from across the internet for easy browsing, it’s as productivity-focuses as you might expect.

Dawning of the age of Aquarius

Canonical’s Stuart Langridge (aquarius on IRC, for those who don’t get the reference) is our resident audio-phile, which might explain why he’s written two music apps with the Ubuntu SDK, one for Ext.fm and another for Ubuntu One’s Music Streaming service.

Zeegaree

Developer Micha? Pr?dotka is porting his desktop timer app Zeegaree to the Ubuntu SDK

GPS Workout tracker

Fitness trackers are becoming more and more popular, especially as mobile apps.  Ready to meet this demand is Marin Bareta and his workout tracker for Ubuntu Touch

uQQ

QQ, the popular instant messaging service out of China, is getting it’s own native uQQ Ubuntu SDK client thanks to developer ? ? (shared to me by Szymon Waliczek)

Resistor Color Codes

I’m not electrical engineer, so I don’t know exactly what this does, but if you do I bet it would be handy to have available in your pocket, so thank Oliver Marks for making it.

Stock Tracker

Last but not least, I just saw this stock price tracker from Robert Steckroth

If you are writing an Ubuntu SDK app, or have come across one that I haven’t blogged about yet, be sure to drop me an email or ping me on IRC.  I get the feeling this isn’t the last SDK Apps update I’ll be posting.