Android studio会为新建的程序创建一个菜单：\app\src\main\res\menu\menu_main.xml <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=".MainActivity" > <item android:id="@+id/action_settings" android:title="@string/action_settings" android:orderInCategory="100" android:icon="@drawa ...