title: ConstraintLayout: Unable to scale image to fit a ratio in RecyclerView
body: <ul>
  <li>I have a recycler view with StaggeredGridLayoutManager. </li>
  <li>Within in I have custom items/views. </li>
  <li>Each item is defined as a ConstraintLayout where there is an image which is supposed to have a constant aspect ratio.</li>
  <li>But the image is to still be able to scale to fit the width of each span. </li>
  <li>And then the height should be adjusted according to the ratio. </li>
  </ul>
  
  <p>But somehow the images are not maintaining the aspect ratio.</p>
  
  <p>Here are the xml files and code to create the recycler view:</p>
  
  <p>item.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:padding="10dp"&gt;
  
  
      &lt;ImageView
          android:id="@+id/image"
          android:layout_width="0dp"
          android:layout_height="0dp"
          android:adjustViewBounds="true"
          android:scaleType="centerCrop"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintLeft_toLeftOf="parent"
          app:layout_constraintRight_toRightOf="parent"
          app:layout_constraintTop_toTopOf="parent"
          app:layout_constraintDimensionRatio="16:9"
          tools:src="@drawable/ic_logo" /&gt;
  
  
      &lt;TextView
          android:id="@+id/title"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          app:layout_constraintLeft_toLeftOf="parent"
          app:layout_constraintRight_toRightOf="parent"
          app:layout_constraintBottom_toBottomOf="@+id/image"
          android:textColor="@color/white"
          tools:text="SAMPLE"
          android:paddingBottom="10dp"
          android:layout_margin="5dp"/&gt;
  
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>activity.xml</p>
  
  <pre><code>&lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_margin="10dp"&gt;
  
      &lt;android.support.v7.widget.RecyclerView
          android:id="@+id/recycler_view"
          android:layout_marginTop="5dp"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:layout_alignParentStart="true" /&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>Code to generate the whole view:</p>
  
  <pre><code>adapter = new SampleAdapter(list);
          StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
          sampleRecyclerView.setLayoutManager(manager);
          sampleRecyclerView.setAdapter(adapter);
  </code></pre>
  
  <p>The width of each item is set fine and fits the width of each column span.
  But the height is not maintained and is very little. </p>
  
  <p>Could someone please help?</p>
  
  <p>Thanks</p>