In JavaFX, is binding an alternative to action-listener ?

Question

Hi , I was wondering if in JavaFX, binding can be an alternative to action listener/events ? Can we handle all actions with binding instead of event handling ?

Answer 1

Bindings can't be used as an alternative to handling events that represent a user action, such as ActionEvents, MouseEvents, or KeyEvents. ActionEvents are generated when the user takes a specific action, such as pressing a button, or pressing the Enter key in a TextField. There is nothing you can really bind to in this situation.
JavaFX defines a Property API which enables the creation of observable properties (and observable values, of which observable properties are a specific example). You can register ChangeListeners with these observable properties to be notified when their values change. So for example, TextField has a textProperty containing the value of the text in the text field. If you register a change listener with the text field's textProperty, it will be notified whenever the text in the text field changes. (Note that the notification will happen essentially on every key stroke in the text field, not just when the user commits a value with Enter.)
Bindings present a simpler alternative to a particular use case for change listeners on these properties: namely when the change listener would simply update the value of another property. For example the following:
final Label label = new Label();
final TextField textField = new TextField();
final VBox vbox = new VBox();
vbox.getChildren().addAll(label, textField);
label.textProperty().bind(textField.textProperty());
will cause the label to change to match the text in the text field.
See Using JavaFX Properties and Binding | JavaFX 2 Tutorials and Documentation for a fuller discussion of properties and binding.