For RelativeLayout
:
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/fab"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
... />
For CoordinatorLayout
, you should use android:layout_gravity="end|bottom"
For ConstraintLayout
:
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:id="@+id/fab"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
... />
See this answer for more information.