title: How to get notified when property changes in Android databinding?
body: <p>I would like to get notified when property changes in my variable.</p>
  
  <p>In my Activity:</p>
  
  <pre><code>    viewDataBinding = DataBindingUtil.setContentView(this, R.layout.list);
      viewDataBinding.setViewFilter(viewFilter);
  </code></pre>
  
  <p>My model:</p>
  
  <pre><code>public class ViewFilter extends BaseObservable {
      private String priceFrom;
  
      public ViewFilter() {
      }
  
      @Bindable
      public String getPriceFrom() {
          return priceFrom;
      }
  
      public void setPriceFrom(String priceFrom) {
          this.priceFrom = priceFrom;
          notifyPropertyChanged(BR.priceFrom);
      }
  }
  </code></pre>
  
  <p>My layout:</p>
  
  <pre><code>&lt;data&gt;
      &lt;variable
          name="viewFilter"
          type="com.example.ViewFilter" /&gt;
  &lt;/data&gt;
  
                  &lt;EditText
                      android:id="@+id/edtListPriceFrom"
                      android:layout_width="match_parent"
                      android:layout_height="wrap_content"
                      android:digits="0123456789."
                      android:inputType="numberDecimal|numberSigned"
                      android:text="@={viewFilter.priceFrom}" /&gt;
  </code></pre>
  
  <p>When I want to add listener:</p>
  
  <pre><code>    viewFilter.addOnPropertyChangedCallback(new OnPropertyChangedCallback() {
          @Override
          public void onPropertyChanged(Observable sender, int propertyId) {
  </code></pre>
  
  <p>It doesn't get called.</p>
  
  <p>What should I do to have working property change notifications?</p>