How to add Toolbar In android Programming

Hello Friend's

now in android programming all is want advance technology like martial design  so i want to share how to add tool in activity ..

Main . xml

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 

   xmlns:tools="http://schemas.android.com/tools"  

  android:layout_width="match_parent"    

android:layout_height="match_parent"
    tools:context="com.example.kogta.androidadvance.MainActivity">


    <include        

android:id="@+id/app_bar"  

      layout="@layout/app_bar"/>

    <TextView       

 android:layout_below="@+id/app_bar"  

      android:layout_width="wrap_content"      

  android:layout_height="wrap_content"      

  android:text="Hello World!" />
</RelativeLayout>

create app_bar.xml file

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar 
xmlns:android="http://schemas.android.com/apk/res/android"  
  android:layout_width="match_parent"   
 android:layout_height="wrap_content"   
 android:background="#CCC">

</android.support.v7.widget.Toolbar>




java file

package com.example.kogta.androidadvance;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;


    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        toolbar=(Toolbar) findViewById(R.id.app_bar);
        setSupportActionBar(toolbar);
    }

    @Override    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.   
     getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will      
  // automatically handle clicks on the Home/Up button, so long       
 // as you specify a parent activity in AndroidManifest.xml.      
  //int id = item.getItemId();

        //noinspection SimplifiableIfStatement      
  if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}