Overriding onBackPressed for AccountKit functionality

MainActivity.java

@Override
public void onBackPressed() {
    if(doubleBackToExitPressedOnce){
        Intent a = new Intent(Intent.ACTION_MAIN);
        a.addCategory(Intent.CATEGORY_HOME);
        a.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(a);
    }
    else{
        Toast.makeText(this, "Please click again BACK to exit", Toast.LENGTH_SHORT).show();
        doubleBackToExitPressedOnce = true;


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