Opening Flashlight of Galaxy Nexus

I am developing an app which needs to open the flashlight of my Galaxy Nexus device. I have referred to the post here LED flashlight on Galaxy Nexus controllable by what API? ``` public class TestCamera extends Activity implements SurfaceHolder.Callback{ Camera mCamera; public static SurfaceView preview; public static SurfaceHolder mHolder; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.main); preview = (SurfaceView) findViewById(R.id.camSurface); mHolder = preview.getHolder(); mCamera = Camera.open(); try { mCamera.setPreviewDisplay(mHolder); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } Button onLEDbtn = (Button) findViewById(R.id.onLED_btn); onLEDbtn.setOnClickListener(new OnClickListener(){ public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(getApplicationContext(), "test", Toast.LENGTH_SHORT).show(); Parameters params = mCamera.getParameters(); params.setFlashMode(Parameters.FLASH_MODE_TORCH); mCamera.setParameters(params); mCamera.startPreview(); } }); } } public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // TODO Auto-generated method stub } public void surfaceCreated(SurfaceHolder holder) { // TODO Auto-generated method stub mHolder = holder; try { mCamera.setPreviewDisplay(mHolder); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void surfaceDestroyed(SurfaceHolder holder) { // TODO Auto-generated method stub mCamera.stopPreview(); mHolder = null; } } ``` Manifest: ``` <uses-permission android:name="android.permission.CAMERA" /> <uses-feature android:name="android.hardware.camera" /> ``` However, I still cant switch on the flashlight. Could anyone point out my errors? Thanks