Android Camera LED light goes to Off after 2 seconds?

Question

I am using the camera flash light in my application, I was done coding for that, it's working on/off the light. but after 2 seconds it goes to off. If I press the on button again it was giving force close. This is the code i am using for this, please help me.

I want this like if user presses the on button light On, upto user press Off button.

private void processOffClick()  {

    //togglebutton.setButtonDrawable(R.drawable.offbutton);
    System.out.println("in off state");
    if( cam != null ){
        cam.stopPreview();
        cam.release();
    }
}
private void processOnClick()  {

    //togglebutton.setButtonDrawable(R.drawable.onbutton);
    System.out.println("in on state");       
    cam = Camera.open();     
    Parameters params = cam.getParameters();
    params.setFlashMode(Parameters.FLASH_MODE_ON);
    cam.setParameters(params);

    cam.startPreview();
    cam.autoFocus(new AutoFocusCallback() {
        public void onAutoFocus(boolean success, Camera camera) {
        }
    });      
}

Answer 1

put the lines:

Parameters params = cam.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_ON);
cam.setParameters(params);

in processOffClick instead of putting it in processOnClick like that:

boolean clicked = false;
private void processOffClick()  {

  //togglebutton.setButtonDrawable(R.drawable.offbutton);
  clicked = false;
  System.out.println("in off state");
  if( cam != null ){
      cam.stopPreview();
      cam.release();
  }
}
private void processOnClick()  {
  clicked = true;
  //togglebutton.setButtonDrawable(R.drawable.onbutton);
  System.out.println("in on state");       
  cam = Camera.open();     
  Parameters params = cam.getParameters();
  params.setFlashMode(Parameters.FLASH_MODE_ON);

  while(clicked)  { 
     cam.setParameters(params);

     cam.startPreview();
        cam.autoFocus(new AutoFocusCallback() {
           public void onAutoFocus(boolean success, Camera camera) {
        }
     });
  } 
}

It might work, i didn't check the code

I added a while loop so it would hold the flash and the focus until its unclicked.

Answer 2

My experience says, that flash mode ought to be "TORCH" ( if supported ) and it is started only when you start preview. However, cameras behave very differently on different devices and not always as advertised in their capabilities descrioptors

Answer 3

1.Turn on

camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();

2. Turn off

camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();

And, put following permission on AndroidManifest.xml.

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

see this one http://www.mkyong.com/android/how-to-turn-onoff-camera-ledflashlight-in-android/