ChintanRathod

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"

ChintanRathod

 @Override  
 public void onBackPressed() {  
   if (doubleBackToExitPressedOnce) {  
     super.onBackPressed();  
     return;  
   }  
   this.doubleBackToExitPressedOnce = true;  
   Toast.makeText(this, "Press once again to exit", Toast.LENGTH_SHORT).show();  
   new Handler().postDelayed(new Runnable() {  
     @Override