title: OnClickListener not fired on ConstraintLayout
body: <p>On my android app project i have to make a button with a ProgressBar on background and two TextView.</p>
  
  <p>I make a first attempt like this:</p>
  
  <pre><code>    &lt;android.support.constraint.ConstraintLayout
          android:id="@+id/keyboard_touch_1"
          android:layout_width="60dp"
          android:layout_height="85dp"
          android:layout_marginBottom="150dp"
          android:layout_marginStart="10dp"
          android:focusable="true"
          android:clickable="true"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintStart_toStartOf="parent"&gt;
  
          &lt;ProgressBar
              android:id="@+id/keyboard_touch_1_progress_bar"
              style="@android:style/Widget.ProgressBar.Horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:indeterminate="false"
              android:max="100"
              android:progress="50"
              android:progressDrawable="@drawable/button_progress_bar_default"
              android:clickable="false"
              android:focusable="false" /&gt;
  
          &lt;TextView
              android:id="@+id/keyboard_touch_1_score"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_alignParentStart="true"
              android:layout_marginEnd="8dp"
              android:layout_marginTop="8dp"
              android:text="2"
              android:textColor="@color/colorAccent"
              android:textSize="11dp"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintTop_toTopOf="parent"
              tools:text="3"
              android:clickable="false"
              android:focusable="false" /&gt;
  
          &lt;TextView
              android:id="@+id/keyboard_touch_1_letter"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_alignParentStart="true"
              android:layout_marginTop="13dp"
              android:text="A"
              android:textColor="@color/colorAccent"
              android:textSize="45dp"
              app:layout_constraintBottom_toBottomOf="parent"
              app:layout_constraintEnd_toEndOf="parent"
              app:layout_constraintStart_toStartOf="parent"
              app:layout_constraintTop_toTopOf="parent"
              android:clickable="false"
              android:focusable="false" /&gt;
  
      &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>It looks good but when i attempt to add an OnClickListener it doesn't work correctly.</p>
  
  <pre><code>keyboard_touch_1.setOnClickListener {
      Toast.makeText(this, "IT WORKS !!!", Toast.LENGTH_SHORT).show()
  }
  </code></pre>
  
  <p>The OnClickListener is not fired and i have no idea of why. It's probably very simple but i doesn't understand why.</p>
  
  <p>Thanks in advance.</p>