I only write QML app with Qt 5.1.1 running on Mac & Windows.
Anyone know what's the version of Qt for Embedded System integrated in the uclinux?
Do the Qt on uclinux support QML? Do I need to re-implement the UI with Qt widgets in C++ to run it on the uclinux?
First and foremost, please do not ask several subquestions in a question.
Anyone know what's the version of Qt for Embedded System integrated in the uclinux?
There is no such a thing. Qt 5 is meant to be well supported for embedded, too, without external third-party projects.
That being said, you may ask Digia about their embedded plans, like Boot2Qt and so on.
Do the Qt on uclinux support QML?
That is the wrong question around. The correct question is whether Qt/QML suppports uclinux. I do not think this will work off-hand, no. You will probably start writing a custom mkspecs file for your scenario and fix lots of issues.
Do I need to re-implement the UI with Qt widgets in C++ to run it on the uclinux?
That would probably be even worse as they are having a lot of overhead in terms additional layer. What I would suggest is to forget about QML for now, and try to bring up a simple screen with QScreen.
As stated, I do not think even that will work off-hand, but if you are enthusiastic, you could get it work.
Since Qt 5 has a hard dependency on the standard library these days, your first task is to get that building againt your mmu-free uclibc. There was some discussion about that here.
But honestly, you may be better off with some lightweight gui framework that supports framebuffer for rendering. Qt is big and not properly tested on minimal systems.