3.App Resources-Resource Types/Menu Resource

//res/menu/example_menu.xml
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@+id/item1"
          android:title="item1"
          android:showAsAction="ifRoom|withText"/>
    
    <item android:id="@+id/submenu"
          android:title="submenu_title"
          android:showAsAction="ifRoom|withText" >
        <menu>
            <item android:id="@+id/submenu_item1"
                  android:title="submenu_item1" />
            <item android:id= "@+id/submenu_item2"
                  android:title="submenu_item2" />
        </menu>
    </item>
    
    <group android:id="@+id/group">
        <item android:id="@+id/group_item1"
              android:title="group_item1" />
        <item android:id="@+id/group_item2"
              android:title="group_item2" />
    </group>
    
</menu>

public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.example_menu, menu);
    return true;
}