How to exit on double back press with showing the snackbar dialogue of exit?

Question

I wanted to make a snackbar dialog on double press to exit...(java)

Requested with these

1. On 1st time back pressed show dialogue " press back again to exit " for 2 seconds

2. On pressing back again show "do you want to exit ? " with the confirmation button for 2 seconds

As like below -

Answer 1

Create id for your layout in activity_main

CoordinatorLayout coordinatorLayout;

@Override
public void onBackPressed() {     
    coordinatorLayout= (CoordinatorLayout) findViewById(R.id.coordinatorLayout);
if (!doubleBackToExitPressedOnce) {
            this.doubleBackToExitPressedOnce = true;
            Snackbar.make(coordinatorLayout, "Do you really want to exit?", Snackbar.LENGTH_LONG)
                .setAction("YES", new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    //button action here
                    System.exit(0);
                }
            }).setActionTextColor(Color.YELLOW)
              .show();
            new Handler().postDelayed(new Runnable() {

                @Override
                public void run() {
                    doubleBackToExitPressedOnce = false;
                }
            }, 2000);
        } 

Hope this helps