SetState() is not working in fullscreen video

[techuzRaju]

I am adding watermark at random position of video. It is working proper in normal screen view. but when I switch to full screen mode the position of watermark is not updating.

Here's my code to achieve this :

void timer(isFullScreen) async { if (!courseController.isTimerActive) { Timer.periodic(_duration, (timer) { if (mounted) {

      // check if the widget is still mounted
      setState(() {
        print('isFullScreen::->$isFullScreen');
        
        if(isFullScreen){
          var top = (Random().nextDouble() * (MediaQuery.of(context).size.height - 550.sp)).toString();
          if(top.contains("-")){
            top = top.substring(0,1);
          }
          var left = (Random().nextDouble() * (MediaQuery.of(context).size.width - 100.sp)).toString();
          if(left.contains("-")){
            left = left.substring(0,1);
          }
          courseController.topPosition.value = double.parse(top);
          courseController.leftPosition.value = double.parse(left);
        } else {
          courseController.topPosition.value = Random().nextDouble() * (MediaQuery.of(context).size.height - 550.sp);
          courseController.leftPosition.value = Random().nextDouble() * (MediaQuery.of(context).size.width - 100.sp);
        }
        
      });
    }
  });
  courseController.isTimerActive = true;
}

}

timer(isFullScreen);

Positioned( top: courseController.topPosition.value, left: courseController.leftPosition.value, child: Container( color: Colors.black26, child: Text( courseController.securityCode.value, style: Styles.textFontOpenSansSemiBold( size: 12.sp, color: Styles.blackColor) ), ), ),