Using Toolbar in place of ActionBar:-

Nowadays ActionBar is getting replaced by toolbar, so it is good to use or get handy with new feature of Android i.e "ToolBar" , Here is the way to use toolbar in your Android Activity.

Step 1:- set the app theme in style.xml

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar" >
        <item name="android:windowTranslucentStatus">true</item>
    </style>

Step 2:- Create an xml file toolbar.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="@android:color/holo_blue_dark"
    android:elevation="4dp"
    android:padding="4dp"
    android:theme="@style/ThemeOverlay.AppCompat.Dark" >
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal">

        <ImageView
            android:id="@+id/profile_picture"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/user_pic" />

        <ImageView
            android:id="@+id/setting"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"

            android:background="@drawable/settings" />
    </RelativeLayout>
</android.support.v7.widget.Toolbar>

Step 3:- Include the above designed toolbar into XML file of your main Activity

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

<android.support.v4.widget.DrawerLayout

    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/DrawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:elevation="7dp">


    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

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

        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Flowers" 
            android:layout_gravity="center"
            android:gravity="center_horizontal"
            android:padding="10dp"
            android:textSize="20dp"
            android:background="@android:color/holo_orange_light"/>

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/flowers"/>

    </LinearLayout>
</android.support.v4.widget.DrawerLayout>

Step:4 Set toolbar in your mail activity in onCreate method

Toolbar toolbar;   // Declaring the Toolbar Object
 toolbar = (Toolbar) findViewById(R.id.headertoolbar);  // Assinging  toolbar object        
  setSupportActionBar(toolbar);  //setting the the Action bar to our toolbar