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