Activity lifecycle - onCreate called on every re-orientation

Question

I have a simple activity that loads a bitmap in onCreate. I find that if I rotate the device I can see from the logs that onCreate called again. In fact, because all instance variables are set to default values again I know that the entire Activity has been re-instantiated.

After rotating 2 times I get an FC because not enough memory can be allocated for the bitmap. (Are all instances of the activty still alive somewhere? Or does the GC not clean up fast enough?)

@Override public void onCreate(Bundle savedInstanceState) {     File externalStorageDir = Environment.getExternalStorageDirectory();     File picturesDir = new File(externalStorageDir, "DCIM/Camera");     File[] files = picturesDir.listFiles(new FilenameFilter(){         public boolean accept(File dir, String name) {             return name.toLowerCase().endsWith(".jpg");         }});     if (files.length > 0) {         Bitmap bm = BitmapFactory.decodeStream(new FileInputStream(files[0]));         ImageView view = (ImageView) findViewById(R.id.photo);         view.setImageBitmap(bm);     } } 

From all that I read, onCreate should be called once during the lifetime of an application. Am I wrong about this? How can re-orienting the device cause the activity to be recreated?

Answer 1

android:configChanges="keyboardHidden|orientation|screenSize" 

Caution: Beginning with Android 3.2 (API level 13), the "screen size" also changes when the device switches between portrait and landscape orientation. Thus, if you want to prevent runtime restarts due to orientation change when developing for API level 13 or higher (as declared by the minSdkVersion and targetSdkVersion attributes), you must include the "screenSize" value in addition to the "orientation" value. That is, you must decalare android:configChanges="orientation|screenSize". However, if your application targets API level 12 or lower, then your activity always handles this configuration change itself (this configuration change does not restart your activity, even when running on an Android 3.2 or higher device).

http://developer.android.com/guide/topics/resources/runtime-changes.html

Answer 2

Activity is recreated after each rotation by default. You can override this behaviour with configChanges attribute of the activity tag in AndroidManifest. For further details and different options, see http://developer.android.com/guide/topics/resources/runtime-changes.html