# InverseBindingListener

# InverseBindingListener

`
public


interface
InverseBindingListener
`  
`


`

|--------------------------------------------|
| android.databinding.InverseBindingListener |

<br />

*** ** * ** ***

A listener implemented by all two-way bindings to be notified when a triggering change happens. For example, when there is a two-way binding for android:text, an implementation of`InverseBindingListener`will be generated in the layout's binding class.  

```
 private static class InverseListenerTextView implements InverseBindingListener {
     @Override
     public void onChange() {
         mObj.setTextValue(mTextView.getText());
     }
 }
 
```

A[BindingAdapter](https://developer.android.com/reference/android/databinding/BindingAdapter)should be used to assign the event listener. For example,`android:onTextChanged`will need to trigger the event listener for the`android:text`attribute.  

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

<br />

## Summary

|                                                                                             ### Public methods                                                                                             ||
|------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| ` abstract void` | ` `[onChange](https://developer.android.com/reference/android/databinding/InverseBindingListener#onChange())`() ` Notifies the data binding system that the attribute value has changed. |

## Public methods

### onChange

```
void onChange ()
```

Notifies the data binding system that the attribute value has changed.

<br />

-

  ## Annotations

  - [Bindable](https://developer.android.com/reference/android/databinding/Bindable)
  - [BindingAdapter](https://developer.android.com/reference/android/databinding/BindingAdapter)
  - [BindingConversion](https://developer.android.com/reference/android/databinding/BindingConversion)
  - [BindingMethod](https://developer.android.com/reference/android/databinding/BindingMethod)
  - [BindingMethods](https://developer.android.com/reference/android/databinding/BindingMethods)
  - [InverseBindingAdapter](https://developer.android.com/reference/android/databinding/InverseBindingAdapter)
  - [InverseBindingMethod](https://developer.android.com/reference/android/databinding/InverseBindingMethod)
  - [InverseBindingMethods](https://developer.android.com/reference/android/databinding/InverseBindingMethods)
  - [InverseMethod](https://developer.android.com/reference/android/databinding/InverseMethod)
-

  ## Interfaces

  - [DataBindingComponent](https://developer.android.com/reference/android/databinding/DataBindingComponent)
  - [InverseBindingListener](https://developer.android.com/reference/android/databinding/InverseBindingListener)
  - [Observable](https://developer.android.com/reference/android/databinding/Observable)
  - [ObservableList](https://developer.android.com/reference/android/databinding/ObservableList)
  - [ObservableMap](https://developer.android.com/reference/android/databinding/ObservableMap)
-

  ## Classes

  - [BaseObservable](https://developer.android.com/reference/android/databinding/BaseObservable)
  - [CallbackRegistry](https://developer.android.com/reference/android/databinding/CallbackRegistry)
  - [CallbackRegistry.NotifierCallback](https://developer.android.com/reference/android/databinding/CallbackRegistry.NotifierCallback)
  - [DataBindingUtil](https://developer.android.com/reference/android/databinding/DataBindingUtil)
  - [ListChangeRegistry](https://developer.android.com/reference/android/databinding/ListChangeRegistry)
  - [MapChangeRegistry](https://developer.android.com/reference/android/databinding/MapChangeRegistry)
  - [MergedDataBinderMapper](https://developer.android.com/reference/android/databinding/MergedDataBinderMapper)
  - [Observable.OnPropertyChangedCallback](https://developer.android.com/reference/android/databinding/Observable.OnPropertyChangedCallback)
  - [ObservableArrayList](https://developer.android.com/reference/android/databinding/ObservableArrayList)
  - [ObservableArrayMap](https://developer.android.com/reference/android/databinding/ObservableArrayMap)
  - [ObservableBoolean](https://developer.android.com/reference/android/databinding/ObservableBoolean)
  - [ObservableByte](https://developer.android.com/reference/android/databinding/ObservableByte)
  - [ObservableChar](https://developer.android.com/reference/android/databinding/ObservableChar)
  - [ObservableDouble](https://developer.android.com/reference/android/databinding/ObservableDouble)
  - [ObservableField](https://developer.android.com/reference/android/databinding/ObservableField)
  - [ObservableFloat](https://developer.android.com/reference/android/databinding/ObservableFloat)
  - [ObservableInt](https://developer.android.com/reference/android/databinding/ObservableInt)
  - [ObservableList.OnListChangedCallback](https://developer.android.com/reference/android/databinding/ObservableList.OnListChangedCallback)
  - [ObservableLong](https://developer.android.com/reference/android/databinding/ObservableLong)
  - [ObservableMap.OnMapChangedCallback](https://developer.android.com/reference/android/databinding/ObservableMap.OnMapChangedCallback)
  - [ObservableParcelable](https://developer.android.com/reference/android/databinding/ObservableParcelable)
  - [ObservableShort](https://developer.android.com/reference/android/databinding/ObservableShort)
  - [OnRebindCallback](https://developer.android.com/reference/android/databinding/OnRebindCallback)
  - [PropertyChangeRegistry](https://developer.android.com/reference/android/databinding/PropertyChangeRegistry)
  - [ViewDataBinding](https://developer.android.com/reference/android/databinding/ViewDataBinding)
  - [ViewStubProxy](https://developer.android.com/reference/android/databinding/ViewStubProxy)