Thanks to some help from Dustin and from Julian Dolce I've solved my problem.
For everyone else's benefit, here are Julian's suggestions what to look for:
- When applications are minimized the applications window buffers are destroyed to free up memory on the device. So when you maximize it again, it must re-create the window buffers. The activity indicator appears when the system is waiting for the application to post to the window so it can transition it properly to it's maximized state.
- Somethings that may make this happen more then others is if you are doing any processing in your apps Event.ACTIVATE event. Any processing here or additional rendering may cause it to come up slower.
- Also, if your application is using gpu renderMode it needs to upload all of the textures back to the GPU. So if there are lots of different textures you may find it will take a while to upload.
In my case the problem was definitely the second point. (I suspect that the timing betwen Event.ACTIVATE and IowWindowEvent.WINDOW_STATE_CHANGED has changed slightly from earlier DevAlpha builds, so that the problem never showed up before)
So the way it's working for me now is this: use an onActivate handler only to turn QNXSystem.system.powerMode back to NORMAL (if you've changed it before). Pack anything else that needs to be done when the app resumes into a separate function and execute when your onWindowStateChanged handler detects IowWindowState.NORMAL.
Thanks again, Dustin & Julian!
