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ListenerUtil

public class ListenerUtil
extends Object

java.lang.Object
↳	android.databinding.adapters.ListenerUtil

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Utility class that helps with tracking listeners for views from binding adapters.

Summary

Public constructors
ListenerUtil()

Public methods
static <T> T	getListener(View view, int listenerResourceId) Returns the previous value for a listener if one was stored previously with trackListener(View, Object, int)
static <T> T	trackListener(View view, T listener, int listenerResourceId) This method tracks listeners for a View.

Inherited methods
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait(long arg0, int arg1) final void wait(long arg0) final void wait()

Public constructors

ListenerUtil

ListenerUtil ()

Public methods

getListener

T getListener (View view, 
                int listenerResourceId)

Returns the previous value for a listener if one was stored previously with trackListener(View, Object, int)

Parameters
view	View: The View to check for a listener previously stored with trackListener(View, Object, int)
listenerResourceId	int: A unique resource ID associated with the listener type.

Returns
T	The previously tracked listener. This will be null if the View did not have a previously-tracked listener.

trackListener

T trackListener (View view, 
                T listener, 
                int listenerResourceId)

This method tracks listeners for a View. Only one listener per listenerResourceId can be tracked at a time. This is useful for add*Listener and remove*Listener methods when used with BindingAdapters. This guarantees not to leak the listener or the View, so will not keep a strong reference to either. Example usage:

@BindingAdapter("onFoo")
 public static void addFooListener(MyView view, OnFooListener listener) {
     OnFooListener oldValue = ListenerUtil.trackListener(view, listener, R.id.fooListener);
     if (oldValue != null) {
         view.removeOnFooListener(oldValue);
     }
     if (listener != null) {
         view.addOnFooListener(listener);
     }
 }

Parameters
view	View: The View that will have this listener
listener	T: The listener to keep track of. May be null if the listener is being removed.
listenerResourceId	int: A unique resource ID associated with the listener type.

Returns
T	The previously tracked listener. This will be null if the View did not have a previously-tracked listener.

• Classes

  • Converters
  • ListenerUtil