samples/Support7Demos/res/menu/sample_palette_actions.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2014 The Android Open Source Project

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

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     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
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<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/menu_num_colors"
        android:title="Num Colors"
        app:showAsAction="always">

        <menu>

            <group android:checkableBehavior="single">

                <item
                    android:id="@+id/menu_num_colors_8"
                    android:title="8" />

                <item
                      android:id="@+id/menu_num_colors_12"
                      android:title="12" />

                <item
                    android:id="@+id/menu_num_colors_16"
                    android:title="16"
                    android:checked="true" />

                <item
                    android:id="@+id/menu_num_colors_24"
                    android:title="24" />

                <item
                    android:id="@+id/menu_num_colors_32"
                    android:title="32" />

            </group>

        </menu>

    </item>

</menu>