and your first rect will equal screen size.

It doesn’t matter what you set the width and height to, they’ll scale up to whatever the system uses (when you made the QML app fullscreen as above).

The problem is if you used fixed sizes rather than anchors and fractions of parent size.

I made a wiki topic about this. Feel free to add to it.
http://developer.qt.nokia.com/wiki/Qt_Quick_Donts

A note for the beginners that may read this topic in the future and would ask Where/What is QmlApplicationViewer?

QmlApplicationViewer is a subclass of QDeclarativeView [doc.qt.nokia.com] added by Qt Creator as part of the Qt Quick Application template. For those who want to check its code, you can find it here [qt.gitorious.org] :-)

Back to the topic.

However, in certain situations, you would need a different approach. For example, when your app has so many images that would look strange depending on the aspect ratio difference across devices. In this scenario, loading different qml files and/or resource files for a better adjustment can help.

If you know your UI will be dominated by objects with a relatively fixed size (for example, items that can’t be made any smaller or larger) then you may want to consider an alternative interface for much smaller or much larger devices.
If you have only one fixed size item or other such scenarios, Qt will be able to automatically scale/shrink/stretch it for you if you give it hints.
But I think we answered the OPs question.

Hello, If i use width:320 and height:240……will it refer to pixel resolution of 320*240???
how can we set the width and height…???
Are these dimensions related to LCD width and height or the resolution(320*240)??

It will be 320 and 240 ‘units’.
It depends on what size you specified for your main UI element. If you specified 640 for height, then 320 will take up half of that. If the UI is scaled to 1280 pixels, then your 320 height will correspond to 640 pixels.

Hope that helps.

The idea is that your application will be resolution independent so you don’t need to work out pixels but instead ratios.

Thank you,

If the QML viewer is scaling to fullscreen (320×240) and your main UI element is 320×240, then each unit will be 1 pixel :)

So a 60 unit box will be 60 pixels.

That is okay Sacha….
here i am not using QML viewer to scale it to full screen….
I am using QDeclarativeView to start my QML Application.Is it good approach to proceed or shall i use QML viewer? This is what my code is…

QDeclarativeView view;

And also I m mostly using fixed sizes and positions rather than anchors.Can u plz suggest me on this?

When I say QML Viewer, I simply mean the window that displays your main QML item.

It should all be fine :)