20.1 Creating a Chain

Chains may be implemented either by adding a few lines to the XML layout resource file of an activity or by using some chain specific features of the Layout Editor.

Consider a layout consisting of three Button widgets constrained so as to be positioned in the top-left, top-center and top-right of the ConstraintLayout parent as illustrated in Figure 20-1:

Figure 20-1

To represent such a layout, the XML resource layout file might contain the following entries for the button widgets:

<Button

    android:id="@+id/button1"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

    android:layout_marginStart="8dp"

    android:layout_marginTop="16dp"

    android:text="Button"

    app:layout_constraintHorizontal_bias...