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InverseBindingAdapter

public abstract @interface InverseBindingAdapter
implements Annotation

android.databinding.InverseBindingAdapter


InverseBindingAdapter is associated with a method used to retrieve the value for a View when setting values gathered from the View. This is similar to BindingAdapters:

 @InverseBindingAdapter(attribute = "android:text", event = "android:textAttrChanged")
 public static String captureTextValue(TextView view, CharSequence originalValue) {
     CharSequence newValue = view.getText();
     CharSequence oldValue = value.get();
     if (oldValue == null) {
         value.set(newValue);
     } else if (!contentEquals(newValue, oldValue)) {
         value.set(newValue);
     }
 }
 

The default value for event is the attribute name suffixed with "AttrChanged". In the above example, the default value would have been android:textAttrChanged even if it wasn't provided.

The event attribute is used to notify the data binding system that the value has changed. The developer will typically create a BindingAdapter to assign the event. For example:

 @BindingAdapter(value = {"android:beforeTextChanged", "android:onTextChanged",
                          "android:afterTextChanged", "android:textAttrChanged"},
                          requireAll = false)
 public static void setTextWatcher(TextView view, final BeforeTextChanged before,
                                   final OnTextChanged on, final AfterTextChanged after,
                                   final InverseBindingListener textAttrChanged) {
     TextWatcher newValue = new TextWatcher() {
         ...
         @Override
         public void onTextChanged(CharSequence s, int start, int before, int count) {
             if (on != null) {
                 on.onTextChanged(s, start, before, count);
             }
             if (textAttrChanged != null) {
                 textAttrChanged.onChange();
             }
         }
     }
     TextWatcher oldValue = ListenerUtil.trackListener(view, newValue, R.id.textWatcher);
     if (oldValue != null) {
         view.removeTextChangedListener(oldValue);
     }
     view.addTextChangedListener(newValue);
 }
 

Like BindingAdapters, InverseBindingAdapter methods may also take DataBindingComponent as the first parameter and may be an instance method with the instance retrieved from the DataBindingComponent.

See also:

Summary

Inherited methods

From interface java.lang.annotation.Annotation