Android myth 1/2: Activity.onDestroy()

There’s a common conception that onDestroymarks the end of an Android activity so that you need to cancel all your subscribers/asynctasks/whatever as soon as onDestroy fires.

I believe this is mainly due to the Fragments implementations and the dreaded IllegalStateException but I have always wondered whether you could maintain a strong reference to an activity after onDestroy and do UI stuff there.

So I did a little test there: https://github.com/martinbonnin/TestOnDestroy

private Runnable mChangeContentViewRunnable = new Runnable() {
    @Override
    public void run() {
        Log.d(TAG, "callback!");
        getResources();
        setContentView(new TextView(MainActivity.this));
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.d(TAG, "onCreate");
    setContentView(new FrameLayout(this));

}

@Override
public void onBackPressed() {
    super.onBackPressed();
    Log.d(TAG, "onBackPressed");
    finish();
}

@Override
protected void onDestroy() {
    Log.d(TAG, "onDEstroy");
    new Handler().postDelayed(mChangeContentViewRunnable, 3000);
    super.onDestroy();
}

Turns out it didn’t crash… Am I missing something ? By Martin Bonnin on April 4, 2017.

Canonical link

Exported from Medium on November 9, 2024.