Android Fragment 處理 onBackPress 事件

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        //https://stackoverflow.com/questions/22552958/handling-back-press-when-using-fragments-in-android
        getView().setFocusableInTouchMode(true);
        getView().requestFocus();
        getView().setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {

                if (event.getAction() == KeyEvent.ACTION_UP && keyCode == KeyEvent.KEYCODE_BACK) {

                    // handle back button
                    Toast.makeText(activity, "handle back button", Toast.LENGTH_SHORT).show();

                    playHelper.onBackPressed();
                    return true;

                }

                return false;
            }
        });
    }