Crear un botón en la barra de herramientas de Android

Barra de herramientas con Botón Tutorial

1-Añadir compatibilidad de biblioteca dentro de build.gradle

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'
}

2-Crear un nombre de archivo color.xml para definir los colores Toolbar

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="ColorPrimary">#FF5722</color>
    <color name="ColorPrimaryDark">#E64A19</color>
</resources>

3-Modifica tu archivo style.xml

<resources>     
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

        <item name="colorPrimary">@color/ColorPrimary</item>
        <item name="colorPrimaryDark">@color/ColorPrimaryDark</item>
        <!-- Customize your theme here. -->
    </style>     
</resources>

4-Crear un archivo xml como tool_bar.xml

<?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="@color/colorPrimary"
    android:elevation="4dp" />

5-Incluye el Toolbar en tu main_activity.xml

<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=".MainActivity">

    <include
        android:id="@+id/tool_bar"
        layout="@layout/tool_bar" />

    <TextView
        android:layout_below="@+id/tool_bar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/TextDimTop"
        android:text="@string/hello_world" />

</RelativeLayout>

6-Luego, póngalo dentro de su MainActivity clase

package com.example.hp1.materialtoolbar;

import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;

/* When using AppCompat support library                                                             
 * (you need to extend Main Activity to                                                            
 * ActionBarActivity)
 * ActionBarActivity has deprecated, use AppCompatActivity
 */
public class MainActivity extends ActionBarActivity { 
    // Declaring the Toolbar Object
    private Toolbar toolbar;

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

        // Attaching the layout to the toolbar object
        toolbar = (Toolbar) findViewById(R.id.tool_bar);
        // Setting toolbar as the ActionBar with setSupportActionBar() call
        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);
    }
}

7-Y finalmente, agregue sus "Elementos de botón" a menu_main.xml dentro de /res/menu/ directorio

<?xml version="1.0" encoding="utf-8"?>
   <menu
        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"
        tools:context=".MainActivity">
        <item
            android:id="@+id/action_settings"
            android:orderInCategory="100"
            android:title="@string/action_settings"
            app:showAsAction="never" />
        <item
            android:id="@+id/action_search"
            android:orderInCategory="200"
            android:title="Search"
            android:icon="@drawable/ic_search"
            app:showAsAction="ifRoom"/>                
        <item
            android:id="@+id/action_user"
            android:orderInCategory="300"
            android:title="User"
            android:icon="@drawable/ic_user"
            app:showAsAction="ifRoom" />        
    </menu>