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Posts: 38
Registered: ‎06-07-2010
My Device: BlackBerry Bold 9790
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Unable to switch back to application: a UI - UIE: no face detected

 

Being on a specific screen in my application, when I use the application switcher to switch to another application, I am not able to switch back to my application. The only output generated in the event log when trying to switch back is: a UI - UIE: no face detected

 

These are the steps to reproduce the issue:

  1. I open my application (everything is working fine)
  2. switch to the Event Log application, using the application switcher (assuming the Event Log application is already opened)
  3. clear the event log
  4. try to switch to my application, using the application switcher -> after choosing my application, the application switcher closes but I am still in the Event Log application
  5. refresh the event log
  6. the following output was generated: a UI - UIE: no face detected

The error only occurs on one modal screen, where I use a timer to show a countdown. What does the output "a UI - UIE: no face detected" mean? Could the cause of the issue be that I am using a timer or a modal screen?

 

I'd appreciate any help!

 

Developer
Posts: 16,992
Registered: ‎07-29-2008
My Device: Z10 LE, Z30, Passport
My Carrier: O2 Germany

Re: Unable to switch back to application: a UI - UIE: no face detected

it usually means that your application has no active screen.
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Contributor
Posts: 38
Registered: ‎06-07-2010
My Device: BlackBerry Bold 9790
My Carrier: none

Re: Unable to switch back to application: a UI - UIE: no face detected

thanks for your reply!

 

I show the screen causing the issue by calling UiApplication.getUiApplication.pushModalScreen(...) and the screen is shown. Everything on the screen is working fine as well (interaction, closing, ...). However, the problem only occurs on this screen of the application.

 

Is there a way to determine whether this screen is (for some reason) not the active screen of the application?

Contributor
Posts: 38
Registered: ‎06-07-2010
My Device: BlackBerry Bold 9790
My Carrier: none

Re: Unable to switch back to application: a UI - UIE: no face detected

 

I just solved the issue. It had nothing to do with the output "UIE: no face detected" - i still get this output quite often for different applications. It seems to be a quite common output.

 

The issue was that on the screen, there was one command resulting in a (unobvious) circular call to one of its own callers, which is of course really bad and therefore ended up in a ForcedStackTraceException. So it was just not possible to switch back to the screen because the it was enormously busy (of course) until it was eventually terminated by the OS.

 

Thanks for the help anyway!