title: ImageButton not Showing
body: <p>I'm trying to add an ImageButton at first, and here is the XML that contains it:</p>
  
  <pre><code>&lt;LinearLayout
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="horizontal"
      android:layout_alignParentTop="true"
      android:id="@+id/name_search_layout"
      android:background="@android:color/darker_gray"
     &gt;
  
      &lt;TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:id="@+id/label_name"
          android:text="@string/name_label"
          android:textSize="20sp"
          android:layout_marginLeft="10dp"
          android:layout_marginRight="10dp"
          android:textStyle="bold" /&gt;
  
  
      &lt;EditText
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:id="@+id/text_name"
          android:hint="@string/name_hint"
          android:layout_marginLeft="10dp"
          android:layout_marginRight="10dp"/&gt;
  
      &lt;ImageButton
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:id="@+id/button_expand"
          android:layout_gravity="right"
          android:src="@android:drawable/btn_plus"
          /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>This is inside another LinearLayout, but my button don't appear, it shows like this:</p>
  
  <p><a href="https://i.stack.imgur.com/WvTAD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/WvTAD.png" alt="The button is circulated in blue"></a></p>
  
  <p>How can i make it appear?</p>