45.6 Reviewing the Project

Since the Basic Activity template was selected, the activity contains four layout files. The activity_main.xml file consists of a CoordinatorLayout manager containing entries for an app bar, a toolbar and a floating action button.

The content_main.xml file represents the layout of the content area of the activity and contains a NavHostFragment instance. This file is embedded into the activity_main.xml file via the following include directive:

<include layout="@layout/content_main" />

The floating action button element within the activity_main.xml file reads as follows:

<com.google.android.material.floatingactionbutton.FloatingActionButton

    android:id="@+id/fab"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_gravity="bottom|end"

  ...