title: Adding constraints programmatically
body: <p>What is the translation to java code of the following XML instructions used in a layout definition with a constraint layout?</p>
  
  <pre><code>app:layout_constraintBottom_toBottomOf="@+id/Button1"
  app:layout_constraintTop_toTopOf="@+id/Button1"
  app:layout_constraintLeft_toLeftOf="@+id/Button2"
  app:layout_constraintRight_toRightOf="Button2"
  </code></pre>