title: Android binding adapter passing multiple arguments cause error
body: <p>I am quite new in <code>Android Data Binding</code>. I am following this tutorial: <a href="https://developer.android.com/topic/libraries/data-binding/index.html" rel="noreferrer">Data Binding Library</a>. 
  I am trying to do an adapter that receive multiple parameters. This is my code:</p>
  
  <p><strong>XML</strong></p>
  
  <pre><code>   &lt;ImageView
              android:layout_width="@dimen/place_holder_size"
              android:layout_height="@dimen/place_holder_size"
              android:layout_alignParentRight="true"
              android:layout_alignParentTop="true"
              android:layout_centerVertical="true"
              app:url="@{image.imageUrl}"
              app:size="@{@dimen/place_holder_size}"
              /&gt;
  </code></pre>
  
  <p><strong>BINDING ADAPTER CLASS</strong></p>
  
  <pre><code>public class ViewBindingAdapters extends BaseObservable {
  
  @BindingAdapter({"bind:url", "bind:size"})
  public static void loadImage(ImageView imageView, String url, int size) {
      if (!Strings.isNullOrEmpty(url)) {
          Picasso.with(imageView.getContext()).load(url).resize(size, size).centerCrop().into(imageView);
      }
  }
  ....
  
  
  }
  </code></pre>
  
  <p>But I am getting this error:</p>
  
  <blockquote>
    <p>java.lang.RuntimeException: Found data binding errors.
    ****/ data binding error ****msg:Cannot find the setter for attribute 'app:url' with parameter type java.lang.String on android.widget.ImageView.
    file:... li_image_item.xml
    loc:30:27 - 30:40
    ****\ data binding error ****</p>
  </blockquote>
  
  <p>Does anybody know why??</p>
  
  <p>Thanks in advance!</p>