title: Android dataBinding - @BindingAdapter custom app namespace being ignored
body: <p>I have created a custom bindingAdapter in android and when i pass in the color i want the color to change, this is actually for a test im working on just to make sure it works. Here is the code: 
  here is my view Model for the data binding:</p>
  
  <pre><code>public class User {
  public ObservableInt visible;
  
  public User(int visible) {
      this.visible=new ObservableInt(visible);
  }
  
  
  @BindingAdapter({"app:bindColor"}) //notice the bindColor custom attribute
  public static void setTextColor(TextView view,String color) {
  
      if("green".equals(color))
      view.setTextColor(Color.parseColor("#63f421"));
  
  }
  </code></pre>
  
  <p>}</p>
  
  <p>Now in my xml file which is binded to this model im expected to pass in a color so that the setTextColor method can use it:</p>
  
  <pre><code> &lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;layout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"&gt;
  
  
      &lt;data class="MainActivityBinder"&gt;
          &lt;variable name="user" type="com.example.android.floatingactionbuttonbasic.User"/&gt;
      &lt;/data&gt;
      &lt;LinearLayout
          android:orientation="vertical"
          android:layout_width="match_parent"
          android:layout_height="match_parent"&gt;
  
          &lt;TextView android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:id="@+id/tv_one"
              android:text="my first textview"/&gt;
  
          &lt;TextView android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:id="@+id/tv_two"
              android:text="my second textview"
              android:visibility="@{user.visible}"
              app:bindColor="@{'green'}" //see im passing in the green string here
              android:textColor="@android:color/holo_green_dark"/&gt;
  
      &lt;/LinearLayout&gt;
  &lt;/layout&gt;
  </code></pre>
  
  <p>I am getting the error at runtime time of: </p>
  
  <pre><code>Error:(27, 65) error: package com.example.android.floatingactionbuttonbasic.databinding does not exist
  Warning:Application namespace for attribute app:bindColor will be ignored.
  Error:(24, 33) Identifiers must have user defined types from the XML file. een is missing it 
  Error:Execution failed for task ':Application:compileDebugJavaWithJavac'.
  &gt; java.lang.RuntimeException: Found data binding errors.
  </code></pre>
  
  <p>if i take out the bindingAdapter stuff it works perfectly with the other databinding stuff.  Its just this custom binding thats not working. My project is titled floatingactionbuttonbasic btw. </p>