public class MainActivity extends Activity implements SurfaceHolder.Callback {
 protected static final int TAKE_PHOTO_WITH_DATA = 0;
 private Button takeButton = null;
 private Button identifyButton = null;
 private SurfaceView cSurfaceView;
 private SurfaceHolder sfh;
 Camera camera;

 @Override
 protected void onDestroy() {
  camera.startPreview();
  camera.release();
  super.onDestroy();
 }

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  cSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
  sfh = cSurfaceView.getHolder();
  sfh.addCallback(this);
  sfh.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
  takeButton = (Button) findViewById(R.id.take_picture);
  takeButton.setOnClickListener(new ButtonListner());
  identifyButton = (Button) findViewById(R.id.identify_picture);
  identifyButton.setOnClickListener(new ButtonListner());
 }

 public void onPictureTaken(byte[] data, Camera camera) {
  System.out.println(camera);
 }

 class ButtonListner implements OnClickListener, Camera.PictureCallback {

  public void onClick(View v) {
   switch (v.getId()) {
   case R.id.take_picture:
    camera.takePicture(null, this, this, this);
    break;
   case R.id.identify_picture:
    break;
   }

  }

  public void onPictureTaken(byte[] data, Camera camera) {
   System.out.println("takenpicture");
  }

 }

 public void surfaceCreated(SurfaceHolder holder) {
  camera = Camera.open();
  try {
   Camera.Parameters parameters = camera.getParameters();
   if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) {
    // 這是一個眾所周知但未文件化的特性
    parameters.set("orientation", "portrait");

    // 對於Android 2.2及以上版本
    camera.setDisplayOrientation(90);

    parameters.setRotation(90);
   } else {

    parameters.set("orientation", "landscape");

    camera.setDisplayOrientation(0);

    parameters.setRotation(0);
   }
   camera.setParameters(parameters);
   camera.setPreviewDisplay(holder);
  } catch (IOException exception) {
   camera.release();

  }
  camera.startPreview();
 }

 public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
  camera.startPreview();
 }

 public void surfaceDestroyed(SurfaceHolder holder) {

 }
}