1<?xml version="1.0" encoding="utf-8"?>
2<menu xmlns:android="http://schemas.android.com/apk/res/android" >
3    <group android:checkableBehavior="single">
4        <item android:id="@+id/calibrate"
5              android:title="@string/action_calibrate"
6              android:showAsAction="ifRoom|withText" />
7        <item android:id="@+id/preview_mode"
8              android:title="@string/preview_mode">
9              <menu>
10                  <group android:checkableBehavior="single">
11                      <item android:id="@+id/calibration"
12                            android:title="@string/calibration"
13                            android:checked="true" />
14                      <item android:id="@+id/undistortion"
15                            android:title="@string/undistortion" />
16                      <item android:id="@+id/comparison"
17                            android:title="@string/comparison" />
18                  </group>
19              </menu>
20        </item>
21    </group>
22</menu>
23