Another edition of the Ubuntu App Developer Week and another amazing knowledge sharing fest around everything related to application development in Ubuntu. Brought to you by a range of the best experts in the field, here's just a sample of the topics they talked about: App Developer Strategy, Bazaar, Bazaar Explorer, Launchpad, Python, Internationalization, Launchpad Translations, Unity, Unity 2D, Gedit Developer Plugins, the MyApps Portal, the App Review Board, the UbuntuSoftware Centre, Unity Mail, Launchpad Daily Builds, Ubuntu One APIs, Rapid App Development, Quickly, GooCanvas, PyGame, Unity Launcher, Vala, the App Developer Site, Indicators, Python Desktop Integration, Libgrip, Multitouch, Unity Lenses, Ubuntu One Files Integration, The Business Side of Apps, Go, Qt Quick... and more. Oh my!

And a pick of what they had to say:

We believe that to get Ubuntu from 20 million to 200 million users, we need more and better apps on Ubuntu Jonathan Lange on making Ubuntu a target for app developers

Bazaar is the world's finest revision control system Jonathan Riddell on Bazaar

So you've got your stuff, wherever you are, whichever device you're on Stuart Langridge on Ubuntu One

Oneiric's EOG and Evince will be gesture-enabled out of the box Jussi Pakkanen on multitouch in Ubuntu 11.10

I control the upper right corner of your screen ;-) Ted Gould on Indicators

• Day 1 Summary
• Day 2 Summary
• Day 3 Summary
• Day 4 Summary
• Day 5 Summary (this post)

Ubuntu App Developer Week - Day 5 Summary

Getting A Grip on Your Apps: Multitouch on GTK apps using Libgrip

In his session, Jussi talked about one of the most interesting technologies where Ubuntu is leading the way in the open source world: multitouch. Walking the audience through the Grip Tutorial, he described how to add gesture support to existing applications based on GTK+ 3. He chose to focus on the higher layer of the uTouch stack, where he explained the concepts on which libgrip, the gesture library, is built upon, such as device types and subscriptions. After having explored in detail the code examples, he then revealed that in Oneiric Eye Of GNOME and Evince, Ubuntu's default image viewer and default PDF reader, will be gesture-enabled.

Check out the session log.

Creating a Google Docs Lens

Neil introduced his session explaining the background behind Lenses: a re-architecture effort of the now superseded Places concept to make them more powerful, provide more features and make it easier to add features through a re-engineered API. Lenses create its own instance, add categories, filters and leave the searching to Scopes. The Lenses/Scopes pairs are purely requests for data, independent of the type of UI, and being provided by the libunity library, they can be written in any of the programming languages supported by GObject Introspection (Python, Javascript, C/C++, Vala, etc.). To illustrate all of this concepts, Neil devoted the rest of the session to a real example of creating a Lens for Google Docs.

Check out the session log.

Practical Ubuntu One Files Integration

Another hands-on session from Michael, with a real world example on how to supercharge apps with cloud support. Using his experience in integrating the Ubuntu One Files API to Deja Dup, the default backup application in Ubuntu, he went in detail through the code of a simple program to talk to a user's personal Ubuntu One file storage area. We liked Michael's session so much that it will very soon be featured as a tutorial on developer.ubuntu.com!

Check out the session log and Michael's awesome notes.

Publishing Your Apps in the Software Center: The Business Side

Ubuntu directly benefits from Canonical becoming a sustainable business to support its development, and that's exactly what John talked about. Being responsible for business development in the Ubuntu Software Centre, he's got a privileged  insight on how to make it happen. He started off explaining that the main goal is to present Ubuntu users with a large catalog of apps available for purchase, and then continued concentrating on how to submit paid applications to be published in the Software Centre. A simple 5-step process, the behind-the-scenes work can be summarized in: Canonical helps packaging the app, it hosts the app and provides the payment via pay.ubuntu.com, in a 80%/20% split. Other highlights include the facts that only non-DRM, non-licensed apps cannot be submitted right now, but there is ongoing work to implement license key support, and that MyApps, the online app submission portal, can take any nearly any content: apps with adverts, "free" online game clients and HTML5 apps.

Check out the session log.

Writing an App with Go

Gustavo's enthusiasm for Go, the new programming language created by Google shows every time you start a conversation with him on that topic. And it showed as well on this session, in which he created yet another "Hello world" application in a new language -you guessed-: Go. Along the way, he had time to describe all of the features of this new addition of the extensive family of programming languages: statically compiled with good reflection capabilities, structural typing, interfaces and more.

Check out the session log.

Qt Quick At A Pace

Closing the week on the last -and surprise- session, we had the luxury of having Donald, from the Nokia Qt team, the makers of Qt itself, to talk about Qt Quick. Using a clear and concise definition, Qt Quick is an umbrella term used to refer to QML and its associated tooling; QML being a declarative markup language with tight bindings to Javascript. A technology equally suited to mobile or to the desktop, QML enables developers to rapidly create animation-rich, pixmap-oriented UIs. Through the qtmediahub and Qt tutorial examples, he explored QML's capabilities and offered good practices for succesfully developing QML-based projects.

Check out the session log.

Wrapping Up

Thanks a lot for participating. I hope you enjoyed it  as much as I did, and see you again in 6 months time for another week full with app development goodness!

Ubuntu App Developer Week - Day 3 Summary

Unity Mail: Webmail Notification on Your Desktop

Starting off with a description of the features of Unity Mail, such as displaying webmail unread message count, notifications and mail subjects, we then learned more about how it was developed and the technologies that were used to create it. It's written in Python, using GObject introspection (PyGI) and integrates with Ubuntu through the Unity, Notify and Indicate modules. After describing each one in more detail, Dmitry continued talking about how the app can be translated using Launchpad, and how he uses the Bazaar  source revision control system to work with code history. Wrapping up, he went through the plans for the future: more configuration options, marking all messages as read and the need for a new icon. Any takers? ;)

Check out the session log here.

Launchpad Daily Builds and Rapid Feedback: Writing Recipe Builds

Assuming some previous knowledge on Debian packaging, in his session Jelmer walked the audience through a practical example of a basic recipe build for a small project: pydoctor. Drawing the cooking recipe analogy, package recipes are a description of the ingredients (source code branches) and how to put them together, ending up with a delicious Debian package for users to enjoy. Launchpad can build packages from recipes once or automatically on a daily basis provided the code has changed, conveniently placing the result in a PPA. In the last part of the session, he described in detail the contents of an existing recipe and added some notes on best practices when building from a recipe.

Check out the session log here.

Using the Ubuntu One APIs for Your Apps: An Overview

The idea bahind the Ubuntu One developer programme is to make it easy to add the cloud to your apps and make new apps for the cloud. With this opening line, Stuart delivered a talk about a high-level overview on the cool things you can do as an app developer adding Ubuntu One support. One aspect it data: for example building applications that work on the desktop, on mobile phones and on the web, securely sharing data among users. Another is music: streaming, streaming music and sharing playlists on the desktop, on mobile and from the web, all through a simple REST HTTP API. He also mentioned some examples of cloud enabled applications: Shutter and Deja-Dup, and many other interesting ways to use Ubuntu One to do exciting thigs with data. And you can get started already using the available documentation.

Check out the session log here.

Supercharging Your Apps with Unity Launcher Integration

In his talk, Jason first went through the terminology that covers the elements related to the Unity Launcher, and the bachground behind the Launcher API, implemented in the libunity library. Libunity can be used in many programming languages: Python, C, Vala and others supported by GObject Introspection. Going through what you can do with the Launcher (marking/unmarking apps as urgent, setting object counts, setting progress on objects and adding quicklist menu items to the object), he used Vala snippets to illustrate each feature with code.

Check out the session log here.

Hello Vala: An Introduction to the Vala Language

Vala, a new programming language with C#-like syntax that compiles to C and targets the GObject type system: with a clear statement of what Vala is and what it can do, Luca, a contributor to the project introduced one by one the mostkey features of the language through his "Hello world" example: namespaces, types, classes, properties, keywords and more. As a highlight he mentioned Vala's automatic memory management using reference counting, andits interoperability with other languages, most notably C, but it can also work with many others supported by GObject Introspection. Other cool featuresto note were also error handling on top of GError, support for async operations, closures and DBus client/server, on each of which he elaborated before finishing the session.

Check out the session log here.

The Day Ahead: Upcoming Sessions for Day 3

16.00 UTC - Creating an App Developer Website: developer.ubuntu.com

Ubuntu 11.10 will not only bring new features to the OS itself. In time for the release we'll be launching the new Ubuntu App Developer site, a place for developers to find all the infromation and the resources they need to get started creating, submitting and publishing their apps in Ubuntu. John Oxton, David Planella and many other people have worked to make the next developer.ubuntu.com possible and will tell you all about it.

17:00 UTC - Rapid App Development with Quickly

Quickly is a wrapper that pulls together all the recommended tools and technologies to bring apps from creation and through their whole life cycle in Ubuntu. With an easy set of commands that hide all the complexity for your, it effectively enables developers to follow rapid development principles and worry only about writing code. Michael Terry, from the Quickly development team will be looking forward to guide you through the first steps with this awesome tool.

18:00 UTC - Developing with Freeform Design Surfaces: GooCanvas and PyGame

Have you ever wondered what freeform design surfaces, or canvases are? You probably have now. Well, lucky you then, because Rick Spencer will be here to tell you what they're good for and how to get started with them ;)

19:00 UTC - Making your app appear in the Indicators

In another session on how to integrate with the platform, Ted Gould, the man who knows most about them, will describe how to add indicator features  to your apps, both in terms of panel indicators and messaging menu support.

20:00 UTC - Will it Blend? Python Libraries for Desktop Integration

You certainly will want your app to have that familiar look and feel at home in the OS it's running on, but you'll also want it to use all the backend technologies to integrate even deeper and provide a great user experience. Well, fear not, for Marcelo Hashimoto is here to tell you exactly how to do that!

Looking forward to seeing you all there in a few hours!

Ubuntu App Developer Week - Day 3 Summary

Qt Quick: QML the Language

In his first session, Jürgen gave a short intro to Qt Quick's QML language and how to use it. The first steps were to install Qt and Qt Creator, followed by a description of what Qt Quick is and how developers came up with a declarative way, similar to CSS or JSON to write in the language. All that clear, he then started with the Qt Quick tutorial and code examples that could be run with qmlviewer, the qml interpreter. Onto the second part, he focused on the QML languate, and going into the detail on how to create custom QML components. There were also lots of pointers to the excellent Qt documentation.

Check out the session log here.

Make your applications work in the cloud with Ubuntu One

Stuart gave a great overview on how to add the cloud to existing apps and how to make new apps for the cloud, letting Ubuntu One do all the hard work for you: from managing identities, password renewal to sharing data between applications. And all that on the web, the desktop, mobile... all your stuff everywhere! He then showed us some simple code to sync playlists on the cloud, ready for streaming. File sync is also an important Ubuntu One feature apps can make use of for sharing, and he also went through a couple of the many cool ways you can use it. The last mention was on API documentation, something Stuart is working on in this cycle.

Check out the session log here.

Take control of your desktop easily with DBus

In this session Alejandro showed us in a hands-on and easy to follow way different bits and pieces of D-Bus, and how applications in the desktop can communicate through it. He went through real life examples to show how to do simple tasks and explained how they can be achieved with D-Bus.

Check out the session log here.

Touchégg: Bringing Multitouch Gestures to your Desktop

By José Expósito

Check out the session log here.

Unity: Integrating with Launcher and Places

Mikkel used the intro of the talk to set a couple of things straight: "Places" are going to be called "Lenses" in the next cycle, and libunity does not yet guarantee API or ABI stability. He then followed with the Unity Launcher integration, and how applications can use static quicklists, and more advanced features such as count, progress bar, window flashing and dynamic quicklists. The second part were Places: remote databases that provide data for Unity to render. Through a Python code example he showed us in detail all the aspects of creating a Unity Place.

Check out the session log here.

Tracking Source Code History with Bazaar

Jelmer, in his experience of seasoned Bazaar hacker started off introducing what bzr is: a modern distributed version control system. He then went on with the basics with a hands-on example, going through the creation of a branch, the first commit, and describing several of the most handy bzr commands. As a wrap-up, he showcased more advanced features such as source recipes: scripts that combine branches and build daily Debian packages from them.

Check out the session log here.

The Day Ahead: Upcoming Sessions for Day 4

16:00 UTC
Qt Quick: Elements/Animations/States - Jürgen Bocklage-Ryannel
Another day and more featured Qt content: this time Jürgen will take us through different elements/animations and states Qt Quick provides, and will show us through examples how to make use of them.

17:00 UTC
Qt Quick: Rapid Prototyping - Jürgen Bocklage-Ryannel
If one session weren't enough, here's the continuation: more Qt goodness, this time a hands-on session to develop a small application from start to finish and experience the whole process from the front row.

18:00 UTC
Rapid App Development with Quickly - Michael Terry
Mike will show you how to write applications in no time with the power of Python and Quickly: bringing back the fun in programming.

19:00 UTC
Getting Your App in the Distro: the Application Review Process - Allison Randal
A while back we created an easy process defining how to get applications into Ubuntu, so in order to be able to add them in a matter of weeks, rather than waiting for the next release. Allison, in her Ubuntu Technical Architect and Application Review Board member hat, will walk you through the Application Review Process

20:00 UTC
Adding Indicator Support to your Apps - Ted Gould
Join the man who knows most about indicators in a session that will teach you how to integrate your application even more into Ubuntu. They're slick, robust and consistent: bringing indicator support to your apps.

21:00 UTC
Using Launchpad to get your application translated - Henning Eggers
One of the coolest features of Launchpad is that it helps growing a translation community around your project. You can make your application translatable in Launchpad and be able to deliver it into almost any language. Henning will teach you how to do this, picking up where the previous session on translations left.

Looking forward to seeing you all there!