BlackBerry - Possible to Hide Video Field?

问题:

I want to write an application like a Flashlight (with the help of the camera LED).

Player player = javax.microedition.media.Manager.createPlayer("capture://video?encoding=video/3gpp");

player.realize();

VideoControl videoControl = (VideoControl) player.getControl("VideoControl");
if(videoControl != null)
{
    videoField = (Field)videoControl.initDisplayMode( VideoControl.USE_GUI_PRIMITIVE, "net.rim.device.api.ui.Field" );
    try
    {
        videoControl.setDisplaySize(1, 1);
    }
    catch(Exception e)
    {
        PGLogUtil.logString(e.toString());
    }
    videoControl.setVisible(true);
    add(videoField);

    FlashControl flashControl = (FlashControl)
            player.getControl("javax.microedition.amms.control.camera.FlashControl");
    setFlashlight(true);
}
player.start();

The code above works perfectly, but I want to hide the videoField. When I removed add(videoField) or use videoControl.setVisible(false), the flashlight does not work. Can someone explain why?

How I can turn lights on with a hidden videoField?

回答1:

I just got a bb that had a flash i wanted to try my hands on this same issue. I finally got it to work anyway. On thing i observed during the whole testing time was that if the videoField is hidden like you said, the flash wouldn't work...So the trick i did was

    <pre>
    _videoControl.setDisplaySize( 1 , 1 );
    </pre>

And that did the job for me. You could as well set it to

    <pre>
    _videoControl.setDisplaySize( 0 , 0 );
    </pre>

But whatever you do ... ensure you set

    <pre>
    _videoControl.setVisible(true);
   </pre>

else your flash will not work