How to handle back button when at the starting destination of the navigation component

Question

I\'ve started working with the new navigation component and I\'m really digging it! I do have one issue though - How am I supposed to handle the back button when I\'m at the

Answer 1

/** in your activity **/
private boolean doubleBackToExitPressedOnce = false;
        @RequiresApi(api = Build.VERSION_CODES.M)
        @Override
        public void onBackPressed() {
            int start = Navigation.findNavController(this, R.id.nav_host_fragment).getCurrentDestination().getId();
            if (start == R.id.nav_home) {
                if (doubleBackToExitPressedOnce) {
                    super.onBackPressed();
                    return;
                }
                this.doubleBackToExitPressedOnce = true;
                Toast.makeText(MainActivity.this, "Press back again to exits", Toast.LENGTH_SHORT).show();

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        doubleBackToExitPressedOnce = false;
                    }
                }, 2000);
            } else {
                super.onBackPressed();
            }
        }