javafx.beans.value

Interface ChangeListener<T>

All Known Implementing Classes:

WeakChangeListener

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ChangeListener<T>

A ChangeListener is notified whenever the value of an ObservableValue changes. It can be registered and unregistered with ObservableValue.addListener(ChangeListener) respectively ObservableValue.removeListener(ChangeListener)

For an in-depth explanation of change events and how they differ from invalidation events, see the documentation of ObservableValue.

The same instance of ChangeListener can be registered to listen to multiple ObservableValues.

Since:

JavaFX 2.0

See Also:

ObservableValue

Method Summary

Modifier and Type	Method and Description
void	changed(ObservableValue<? extends T> observable, T oldValue, T newValue) This method needs to be provided by an implementation of ChangeListener.

Method Detail

changed

void changed(ObservableValue<? extends T> observable,
             T oldValue,
             T newValue)

This method needs to be provided by an implementation of ChangeListener. It is called if the value of an ObservableValue changes.

In general is is considered bad practice to modify the observed value in this method.

Parameters:

observable - The ObservableValue which value changed

oldValue - The old value

newValue - The new value