exit dialog android studio

1Best Code 
2
3@Override
4public void onBackPressed() {
5    new AlertDialog.Builder(this)
6           .setMessage("Are you sure you want to exit?")
7           .setCancelable(false)
8           .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
9               public void onClick(DialogInterface dialog, int id) {
10                   ExampleActivity.super.onBackPressed();
11               }
12           })
13           .setNegativeButton("No", null)
14           .show();
15}

1if (dialog.isShowing) {
2     dialog.dismiss()
3}