Release Memory of Particular Activity when it is Destroyed

Question

I have a launcher Activity that load and resize big bitmap as it's background when it opens.

Whenever hit the back button, the Activity is destroyed. But I think the memory is not released yet.

When I open back the app, hit the back button and open it again (repeatedly), I will get a OutOfMemoryError.

I am sorry for this newbie question but I am wondering how do I release the memory whenever an Activity is destroyed?

@Override protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_welcome);      //MARK - movingBackgroundImageView     movingBackgroundImageView = (ImageView) findViewById(R.id.movingBackgroundImageView);     movingBackgroundImageView.setColorFilter(Color.argb(255, 255, 255, 255));     movingBackgroundImageView.setScaleType(ImageView.ScaleType.MATRIX);     movingBackgroundImageView.setAlpha(0.28f);      prepareBackgroundAnimation(); }  private void prepareBackgroundAnimation() {      DisplayMetrics displaymetrics = new DisplayMetrics();     getWindowManager().getDefaultDisplay().getMetrics(displaymetrics);      screenWidth = displaymetrics.widthPixels;     screenHeight = displaymetrics.heightPixels;      movingImageHeight = displaymetrics.heightPixels;     movingImageWidth = 1920.0 / 1080.0 * movingImageHeight;      bitmapImage = BitmapFactory.decodeResource(this.getResources(), R.drawable.moving_background_image);     scaledBitmap = bitmapImage.createScaledBitmap(bitmapImage, (int) movingImageWidth, (int) movingImageHeight, false);     movingBackgroundImageView.setImageBitmap(scaledBitmap);      backgroundImageInBeginning = true;      movingBackgroundImageView.post(new Runnable() {         @Override         public void run() {             movingBackgroundImageView.setImageMatrix(matrix);             moveBackground();         }     }); } 

12-22 13:44:49.549 30885-30885/? E/AndroidRuntime: FATAL EXCEPTION: main Process: id.testingapp.android.TestingApp, PID: 30885 java.lang.OutOfMemoryError: Failed to allocate a 26211852 byte allocation with 14018312 free bytes and 13MB until OOM at dalvik.system.VMRuntime.newNonMovableArray(Native Method) at android.graphics.Bitmap.nativeCreate(Native Method) at android.graphics.Bitmap.createBitmap(Bitmap.java:939) at android.graphics.Bitmap.createBitmap(Bitmap.java:912) at android.graphics.Bitmap.createBitmap(Bitmap.java:843) at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:719) at id.testingapp.android.TestingApp.WelcomeActivity.prepareBackgroundAnimation(WelcomeActivity.java:140) at id.TestingApp.android.TestingApp.WelcomeActivity.onCreate(WelcomeActivity.java:72) at android.app.Activity.performCreate(Activity.java:6283) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758) at android.app.ActivityThread.access$900(ActivityThread.java:177) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:145) at android.app.ActivityThread.main(ActivityThread.java:5942) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)

EDIT:

I have tried to put all these in onDestroyed() but the problem persists

@Override protected void onDestroy() {     finish();     bitmapImage = null;     scaledBitmap = null;     super.onDestroy();     Runtime.getRuntime().gc();     System.gc(); } 

Answer 1

Add following code for it

@Override protected void onDestroy() {     //android.os.Process.killProcess(android.os.Process.myPid());      super.onDestroy();     if(scaledBitmap!=null)             {                 scaledBitmap.recycle();                 scaledBitmap=null;             }       } 

Answer 2

In activity if you're calling the finish() method from is destroyed and all its resources are queued for garbage collection.

So, all memory that was used by this activity will be freed during next GC cycle.

OR

you can try this to clean memory,

@Override public void onDestroy() {     super.onDestroy();     Runtime.getRuntime().gc();       } 

check this details. hope that helps.