It is easier to create the UI using design editor inside Android Studio. If you are comfortable with XML-based text editor, you can use that as well. We will create a simple ViewPager (activity_swap.xml) that will hold two input images inside a CoordinatorLayout as shown in the following code block:
<android.support.v4.view.ViewPager android:id="@+id/container" android:layout_width="0dp" android:layout_height="0dp" android:layout_gravity="center_vertical" app:layout_behavior="@string/appbar_scrolling_view_behavior" app:layout_constraintBottom_toTopOf="@+id/container1" app:layout_constraintHorizontal_bias="0.0" app:layout_constraintLeft_toLeftOf="parent" app:layout_constraintRight_toRightOf="parent" app:layout_constraintTop_toBottomOf= ...
