Wednesday, April 28, 2010

Fighting The Curse Of Plenty: Nokia's Qt SDK

One of the key differences between mobile and desktop development (apart from the obvious GUI stuff) is that applications cover different use cases from their desktop counterparts. How does this difference in application focus and required tool complexity reflect on open, modern, Linux based mobile platforms, and how does Nokia's newly announced Qt SDK address this ?

Android and WebOS took the top-down approach, and made a streamlined development process heavily based on existing technologies (the Java language in the case of Android and web related tech in WebOS). This allowed for fast application development, leveraging existing developer resources and knowledge for the particular platforms, at the expense of making the jump to native code a bit more difficult or the realm of hackers. The very important lesson here was also that they very successfully hid their Linux roots, not making the Linux heritage a drawback (to the point that very few people will actually regard Android as a Linux mobile platform).

However, there was another camp, the bottom-up one, with Maemo/MeeGo and LiMo as the more prominent representatives, which promised most of the desktop technologies in a mobile environment. The advantage should have been the obvious 'just apply whatever technology you know', but in reality, this has slightly backfired up until now. While they proved to be a great basis to hack on and immediately took the hearts of many Linux diehards, there was a steep learning curve that was unappealing to many developers with little Linux background. For example, Maemo's Scratchbox environment and lack of a traditional IDE/SDK are cited being the points where many hobbyist devs gave up on these platforms. In retrospect, these factors sentenced this group of platforms to be seen in the eyes of mainstream end-users as a land of ports and emulators, with the occasional community gem application in the sea of working-but-not-quite-there-yet apps.

Returning to the title - how does this Nokia Qt SDK change any of this, especially with regard to the latter group ? The key is to understand that this is not a classic platform SDK. Let's see what exactly is happening here:

  • While the technologies present in the package (Qt, Qt Creator and the cross-compiling tools) are not new by a long shot, this is the first time they start to appear as a cohesive, focused way of creating applications A-Z style.
  • A classic IDE-style approach is employed that will appeal to many devs used to such tools, while keeping the power of console and functionality of other existing custom tools.
  • It's a toolkit SDK, not a platform SDK. This in turn allows access to the vast array of various platforms and devices. Currently the focus is obviously on Nokia's Symbian and Maemo platforms, but here's where Qt really shines - you're not learning to code Symbian or code Android stuff. The Qt skills you learn are actually just as applicable to the desktop, whether that be Windows, Linux or Mac.
  • Multiplatform authoring tools. Currently Windows and Linux, but my guess is that a Mac version could be produced fairly quickly if serious interest appears.
  • While Qt provides a level of abstraction, the underpinning platform is not being crippled, and thus applications are being able to take full advantage of it.

As you can see, the goal seems to be to provide a streamlined way of producing modern applications for a range of platforms, while avoiding the dumbing down of platforms to make them fit into a particular mold. I hear you say, okay, so you think this Qt SDK thing will take over the world, right ? Well, while not excluding the possibility, there are a few obstacles that the Qt SDK needs to address before going for world domination in the mobile app development arena:

  • Unified (declarative) UI. Cool compilers and cool IDEs do not necessarily mean cool apps. It is paramount that a unified API (based in some form on the Declarative UI of Qt4.7) exists for widgets and app UIs. If each app will have to have it's UI rewritten due do Orbit/DUI/vendor specific/desktop widget issues, that will significantly reduce the appeal of Qt and proliferate curse-of-plenty problems.
  • Do a final release in a reasonable time-frame. Today we have seen a beta to whet our appetite, but the other tools and platforms have a serious headstart. Winning Symbian folks over is a good start (the inclusion of Qt libs on the new Nokia N8 will kickstart this process nicely), but the real race is to get on the radar of developers currently under heavy influence by Android and the iPhone.
  • Go for Android. This topic alone is grounds for another blog post. Technically, it's known to be possible, there is even is a community level Qt for Android port floating around. I will not go in the business/technical reasoning of the dangers/wins of such a move (maybe in another post), but I feel that it needs to be kept at least as an option, an ace up the Qt sleeve if you wish.
  • Add python support. The use of Python Qt bindings has a long and successful history. Python is easy, and on modern hardware, a Python and Qt combination is much less a drag than it ever was on embedded platforms, as proven by PyQt and PySide on Maemo. C++ is not everyone's cup of tea, and Python is an excellent complementary language for it, while maintaining a solid Qt based 'upgrade' path should developers need it. Doing this without switching SDKs or IDEs would go a long way of making Qt even more appealing to new developers.

If you want to take this new SDK for a spin, you can do it here.

Thursday, April 22, 2010

Operation Qt Shuffle

I know you all like (cough) my long winded and analytical articles, but we'll take a short break from that to allow for a service announcement concerning our busy Qt developers, Maemo 5 and your evergreen favourite update, PR1.2

If you're an end user, the short version is - the doors are open for more (and prettier) apps, plus we have a bridge that will make it easy to backport MeeGo apps to Maemo 5. If you're a developer and/or are interested in the gritty details, read on:

[Maemo community council hat]

One of the big changes PR1.2 brought us is official Qt support in the form of Q4.6 in the Nokia SDK and repositories. This change affects all applications depending on Qt currently in extras-devel. We had some talks with Qt/Nokia folks about Qt-related repository changes in Maemo 5 (triggered by aforementioned PR1.2 and potentially again later on by updates to Qt or related components). Here is the short summary:

  1. remove qt4-maemo5 (4.6) after PR1.2
  2. upload Qt 4.7 snapshots as qt4-experimental to extras-devel afterwards
  3. as soon as 4.6 QtMobility is released, get those packages to the nokia-apps repository
  4. remove 4.6 QtMobility from extras-devel
  5. maybe upload new QtMobility packages to extras-devel, but only for qt4-experimental (4.7) and with 'experimental' in the package name
  6. maintainers of bindings and extensions to Qt are encouraged to follow the same nomenclature in their package names (i.e. using experimental in the name if depending on qt4-experimental)
  7. use a Provides/Replaces/etc libqt4-maemo5 clause in the qt4-experimental packages (Qt4.7 packages should be binary compatible with the current 4.6 ones) so the packages can be deprecated peacefully
  8. QML/declarative will be released as part of Qt4.7 (so qt4-experimental only, no 4.6.2/PR1.2 support)

[/Maemo community council hat]

What does this mean in plain English ? The libqt4-maemo5-* package names are deprecated in extras-devel. Use libqt4-experimental-* if you need Qt4.7 features, or libqt4-* if you want Qt4.6. Qt4.5 will no longer be supported after the release of PR1.2

Have a nice day !