Get activity instance

Question

Excuse me for simple question,I'm completely beginner java and android developer. How I can get the instance of Activity in setCameraDisplayOrientation when surfaceChanged is called?

public class MyActivity extends Activity {     private Camera mCamera;     private CameraPreview mPreview;     public final int cameraId = 0;     public Activity activity = null;      @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);      activity = this;           // Create an instance of Camera         mCamera = getCameraInstance();          // Create our Preview view and set it as the content of our activity.         mPreview = new CameraPreview(this, mCamera);         FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);         preview.addView(mPreview);     }      public void setCameraDisplayOrientation(Activity activity,                         int cameraId, android.hardware.Camera camera) {      }      public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {     private SurfaceHolder mHolder;     private Camera mCamera;     ...     public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {         ...         setCameraDisplayOrientation(activity, cameraId, mCamera);         ....     }     } } 

Answer 1

Here is a way to avoid memory leaks using static variable: make static weak reference to Activity instance that will be set in onCreate(Bundle) method.

1. Write in your secondary class something like below:

   public Class SecondClass {     private static WeakReference<Activity> mActivityRef;     public static void updateActivity(Activity activity) {         mActivityRef = new WeakReference<Activity>(activity);     } 

2. Then in onCreate(Bundle) method of your Activity class:

   @Override onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     SecondClass.updateActivity(this);     ... } 

3. Use activity instance this way:

   mActivityRef.get() 

Answer 2

Activity a = (Activity) getContext(); 

As long as you pass the current activity as a context in the constructor, as you are already doing.