Question

I am using the following code in my application’s activity to prevent it from closing my app on back.

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
        }

        // Return
        return super.onKeyDown(keyCode, event);

    }

It does not work. The app is set to be Android 1.6 (API Level 4) compatible. Clicking on my application icon restarts my app at a Splash activity (which is the Main). How can I prevent my app from closing on back?

Answer 1

Have you tried putting the super call in an else block so it is only called if the key is not KEYCODE_BACK ?

/* Prevent app from being killed on back */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {

        // Back?
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            // Back
            moveTaskToBack(true);
            return true;
        }
        else {
            // Return
            return super.onKeyDown(keyCode, event);
        }
    }

In all honesty though, you can’t rely on this because once your app is placed in the background, at any moment it could be recycled for the system to reclaim memory.