How Can I Override the Back Button to Behave Like the Home Button in Android?

Override the Back Button to Mimic the Home Button's Behavior

Proceeding from the traditional behavior of ending an activity's existence upon pressing the back button, you seek an alternative approach that places it in a stopped state instead.

As alluded to in the Android documentation, this is observed in the Music application, where accessing music and subsequently hitting the back button allows playback to continue despite the player activity being out of sight.

To replicate this, several approaches are considered:

• Intercepting the Back Button Press and Calling Home Button Methods: This entails capturing the key press and executing the same actions as the home button would. However, the specific method invocations remain elusive.
• Simulating a Home Button Press: This method revolves around intercepting the back button and injecting a simulated home button press.
• Starting a Home Screen Activity: By triggering a home screen activity from the back button press, the current activity would effectively go into a stopped state.

Preferred Solution:

A simpler approach is to intercept the Back button press and invoke the moveTaskToBack(true) method:

// For Android 2.0 and above
@Override
public void onBackPressed() {
    moveTaskToBack(true);
}

// For pre-Android 2.0
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        moveTaskToBack(true);
        return true;
    }
    return super.onKeyDown(keyCode, event);
}

While the preferred approach is to allow the activity to complete normally and restore its state from a service, moveTaskToBack offers a quick workaround.

Caution:

Note that Android 2.0 introduced the onBackPressed method, which provides alternative guidelines for handling the Back button.

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