修改ActionBar右边默认图标

默认图标识竖直的三个省略号

修改成自定义图标

需要修改主题Theme

    <style name="AppTheme" parent="AppBaseTheme">

        <item name="android:actionOverflowButtonStyle">@style/Action_OverflowButtonStyle</item>
        <!-- All customizations that are NOT specific to a particular API-level can go here. -->
    </style>

     <style name="Action_OverflowButtonStyle" >
        <item name="android:src">@drawable/actionbar_add_icon</item>
    </style>

大功告成