+ // Control what the system back command does.
+ OnBackPressedCallback onBackPressedCallback = new OnBackPressedCallback(true) {
+ @Override
+ public void handleOnBackPressed() {
+ // Prepare to finish the activity.
+ prepareFinish();
+ }
+ };
+
+ // Register the on back pressed callback.
+ getOnBackPressedDispatcher().addCallback(this, onBackPressedCallback);
+