Screen "hangup" on 6220c when closing Player after Alert

[elsenordhagen]

We have a MIDlet that use the camera to take pictures. It works on a lot of devices like N73, N82, 5310 Music Express (series 40), and various models from SonyEricssons, HTC and others.

However, we have a problem with the Nokia 6220c.

What usually happen on the phone:

Open a "form " that is to be filled with a picture.
Select picture area and the camera starts.
Take picture.
Push a "back" button to get back to the form that now show the picture.

On 6220c the "back" button does not seem to work... however, after some testing it works, but no pixels are drawn on the screen - until! you get a timeout of the screen so that it turns "black" - then the form is drawn. Also, if you open the list of running applications (by holding the menu button down) the form appear behind the list of applications. The input continue to work as normal.

This strange behavior continue as long as the application is running. We can open menus in the MIDLet, draw other screens etc.etc. but the result does not become visible before the screen "times out" or we open the list of running apps. Exiting the midlet returns everything to normal.

We have then tried to find what cause the problem. After a day or two of experiments we found out that if an alert is opened before the camera is closed, we get this behavior. The alert typically comes from the system asking the user if its OK to use the camera. However, we get the same problem if the alert stems from a request to use the network or its just a new Alert that we explisitly start.

We write this to notify others that we are having this problem. We also have a faint hope that maybe someone has solved this, or a similar problem before or have some suggestions for a work-around, or see something we have missed out on.

I'll also post if we find a solution :-)

[hartti]

Complete guess:
Are you using threads in your application?
If yes, and if your are using yields, please change them to short sleeps instead.

However, after re-reading your description I am not sure if this really is even a good guess :-(

Hartti

[elsenordhagen]

Thanks for the idea about the thread.

We did some thinking and inspection since this and other types of threading issues might create problems like this. However, we are now quite convinced that our threads are OK. We have also tested on other devices without similar problems.

Thanks again!