Nearly all mobile apps contain some form of global menu that provides access to functions required throughout the app. Menus can be opened in several ways on Android apps, but most commonly used is the Options menu which is accessed from the toolbar or action bar. Options menu items can also appear on the toolbar, as text or graphically.
First, we will add a basic drop-down toolbar menu to implement the functions currently provided by the two buttons. Open the project from the Fragments section and follow these steps:
<item>tag with these three:
<item android:id="@+id/menu_date" android:orderInCategory="100" android:showAsAction="never" android:title="Date and Time" ...