LED flashlight on Galaxy Nexus controllable by what API?

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What I found out is that some devices need a SurfaceView to turn on the LED.

SurfaceView preview = (SurfaceView) findViewById(R.id.PREVIEW);
SurfaceHolder mHolder = preview.getHolder();
mHolder.addCallback(this);
Camera mCamera = Camera.open();
mCamera.setPreviewDisplay(mHolder);

// Turn on LED  
Parameters params = mCamera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_TORCH);
mCamera.setParameters(params);      
mCamera.startPreview();

...

// Turn off LED
Parameters params = mCamera.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_OFF);
mCamera.setParameters(params);
mCamera.stopPreview();
mCamera.release();

Your activity needs to implement SurfaceHolder.Callback:

public void surfaceChanged(SurfaceHolder holder, int format, int width,
        int height) {}

public void surfaceCreated(SurfaceHolder holder) {
    mHolder = holder;
    mCamera.setPreviewDisplay(mHolder);
}

public void surfaceDestroyed(SurfaceHolder holder) {
    mCamera.stopPreview();
    mHolder = null;
}

The surfaceview has to be visible, android:visibility="invisible" or a height and width of 0 won’t work. Unfortunately I didn’t find a good solution to hide it, so I
just gave it a size of 1x1dip and positioned it underneath a button..

**(To expand on above paragraph [Don’t have enough rep to reply, but felt it was useful]) Somewhere in the XML of your current Content View, you want:

<SurfaceView
    android:id="@+id/PREVIEW"
    android:layout_width="1dip"
    android:layout_height="1dip"/>

If you have it inside a RelativeLayout (preferred), you can also do alignParentLeft/Bottom to tuck it in a corner. This method works for my Galaxy Nexus, but it’s a known problem (phone-side) for Droid X (with the .621 update, anyway), and doesn’t work on mine. Great answer, timosch!

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