Espen Eskedal Trolltech XUI future GUI on mobile phones.

This is a blog from the Open Nordic conference in Skien Norway 19-20 june 2008.

Espen has been working Qt for Nokia series 60. Yesterday he became a Nokia employee. Has been working based in Berlin. Will talk about what the typical probmes are when making applications for mobile phones.

• Tools: It is in general hard to get the toolchain up and working. Process tools, memory debuggers. ON the desktop (Desktop bad->annoying) (Mobile nonexisting->annoying). Best of the pack today is probably Microsoft CE.
• APIs: In general too limited or too difficult.
• Platforms: Very bad fragmentation. You need a lot of binaries, a lot of toolchains.

Mobile gui problems:

• Resolutions are different.
  
• Orientations are different. Some devices even have animations when orientations shift.
  
• Custom styles: Styles can change at runtime. Also you may wish th have applications that looks different from others.
  
• Input devices: Huuuge variation. Softkeys, touch screens, multitouch (iphone). You need to take into consideration that the user might have a bunch of different devices.

His thesis:

• QT solves all of these things, at least part of the way.

Showing demo:
Showing qt running on windows mobile. Different parts of Qt running on an HTC thingy under windows mobile. It´s pretty nice :) Most people see no difference between a Qt application and a really native application. Same application running on OpenMoko (XXX Get link to this demo). Same code, but recompiled and deployed. Different resolutions, but looks nice. Uses layouts to handle tings like orientation changes. Senses dpi resolutions etc.

Qt have both GPL2 and GPL3 and commercial licenses. He is now working on Qt for series 60.

His advice to operators: Flat rate. Available interfaces.

Qt 4.4 has webkit in it, has scriptsupport. There is also a crosspatform multimedia toolkit.

Demo of various stuff to build an application.
He explains the signals/slots thingy that Qt is based on.
He demonstrates that Qt has a stylesheet (qss) file that uses the cascading stylesheet syntax, but does layouts on the qt thingy. Doesn´t need recompliation, but is read at runtime. They have a qstyle class than be hacked

his email address espenr (at) trolltech.com epen.riskedal (at) nokia.com

Goal to make phone input/output as well as video input/output. It should be possible to make a video editor . They only support playback for sound now. There is some kind of support now, they wish to do more, many people wish to go in that direction right now, but it´s not there yet.

On licensing: It´s hard. Terrence Barr says that Sun has the same type of issues that Trolltech has. If you are doing something GPL-like, you may have to talk to some GPL-aware lawyers, because there may be differences in the different companies interpretations of the GPL terms.