onResume() called twice in a row after onCreate() > onPause()

Question

I've run into a weird occurrence with regards to my child activity's life-cycle methods. If I launch and close the activity enough times, there eventually comes a point where for some reason, upon launching, onPause gets called immediately after onCreate (skipping onResume), which is then followed by onResume being called twice in a row. This ends up causing a RuntimeException in my onResume.

Here's the code that starts my activity:

Intent intent = new Intent(MainActivity.this, RecorderActivity.class);
startActivityForResult(intent, AV_CAPTURE);

My onPause:

protected void onPause() {
    camera.stopPreview();
    camera.setPreviewCallback(null);
    camera.release();
    camera = null;
    super.onPause();
};

I'm not really sure what else I can provide here, it's all pretty straightforward. finish() is called to close the activity, etc.

I should also probably mention that the activity is being triggered from a Javascript Interface attached to a WebView. Another interesting thing to mention is that setting a breakpoint anywhere in the first code block above seems to prevent the issue from happening.

I mean, I could probably work around it by wrapping `Camera.open()` in a try catch, but I'd really like to know what's going on. — Drazen Bjelovuk, May 28 '14 at 16:12
I see. @Uxonith post makes complete sense as anyway exceptions should be catched. I think, without being sure, that the lauching/closing of activities is too fast so the device is overwhelmed. — Shlublu, May 28 '14 at 16:17
Strange. I have re-read this and it seems that there is no guarantee that onPause() / onResume() are called just once. Just a guarantee they are called, and just an expectation they are once. http://developer.android.com/training/basics/activity-lifecycle/index.html — Shlublu, May 29 '14 at 09:08

score 3 · Answer 1 · answered May 28 '14 at 16:02

While I do not have an answer for the resume being called twice, I do have a link to the Android docs stating that you should always check for exceptions while attempting to open the camera. See here:

http://developer.android.com/guide/topics/media/camera.html#access-camera

In your onPause, make sure that you set your Camera object to null. Then in onResume, only attempt to call getCameraInstance() if your camera is not null.

onResume() called twice in a row after onCreate() > onPause()

1 Answers1