ActionBar菜单更改图标位置

Question

如何更改此菜单的图标？

和这个我的xml文件：

<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="com.niyazdel.jeeb.MainActivity">
<item
    android:id="@+id/main_parent_id"
    android:title="menu"
    app:showAsAction="always"
    android:icon="@drawable/outline_more_vert_white_24">
    <menu>
        <item
            android:id="@+id/action_add"
            android:orderInCategory="1"
            android:title="@string/add"
            android:icon="@drawable/add"
            app:showAsAction="always" />
        <item
            android:id="@+id/action_setting"
            android:orderInCategory="2"
            android:title="@string/action_setting"
            android:icon="@drawable/setting"
            app:showAsAction="always" />
        <item
            android:id="@+id/action_about"
            android:orderInCategory="3"
            android:title="@string/action_about"
            android:icon="@drawable/about"
            app:showAsAction="always" />
    </menu>


</item>