title: Android Data binding - Error:(119, 29) Identifiers must have user defined types from the XML file. main_radio_subscribe is missing it
body: <p>I been trying to control the visibility of a view using the  Implicit Attribute Listeners(<a href="https://halfthought.wordpress.com/2016/03/23/2-way-data-binding-on-android/" rel="noreferrer">reference</a>) in android data binding which allows to access views by id and access attributes like checked, visible etc ..., however when trying to use this, it throws an error like so  </p>
  
  <pre><code>Error:(119, 29) Identifiers must have user defined types from the XML file. addTodo_switch_remind is missing it
  </code></pre>
  
  
  
  <pre><code>&lt;android.support.v7.widget.SwitchCompat
          android:id="@+id/addTodo_switch_remind"
          style="@style/MediumTextViewStyle"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:layout_below="@+id/addTodo_space_project"
          android:text="@string/add_todo_remind_label"
          android:textOff="@string/generic_no_text"
          android:textOn="@string/generic_yes_text" /&gt;
  
      &lt;android.support.v4.widget.Space
          android:id="@+id/addTodo_space_remind"
          style="@style/FormsSpacingStyle"
          android:layout_below="@+id/addTodo_switch_remind" /&gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:layout_below="@id/addTodo_space_remind"
          android:orientation="vertical"
          android:padding="@dimen/grid_box_single"
          android:visibility="@{addTodo_switch_remind.checked ? View.VISIBLE : View.GONE}"&gt;
  </code></pre>