Java FX Chapter 15 Flashcards

Questions and Answers

What is the root class for JavaFX event classes?

javafx.event.Handler

javafx.event.ActionEvent

java.util.EventObject

javafx.event.Event (correct)

What must the handler object's class implement in JavaFX?

The corresponding event-handler interface.

What method is used to handle an event in JavaFX?

handle(T e)

What is the purpose of registration methods in JavaFX?

To register the handler object with the source object Signup and view all the answers

What is an inner class in Java?

A class defined within the scope of another class. Signup and view all the answers

What is a functional interface?

An interface with exactly one abstract method Signup and view all the answers

What is fired whenever a key is pressed in JavaFX?

KeyEvent Signup and view all the answers

What is fired when a mouse button is pressed?

Mouse Event Signup and view all the answers

What defines an observable object in JavaFX?

An instance of Observable. Signup and view all the answers

What class provides core functionalities for animations in JavaFX?

Animation Class Signup and view all the answers

What is an event in programming?

A signal to the program that something has happened. Signup and view all the answers

___ driven programming is a programming paradigm where events drive execution.

Event Signup and view all the answers

What method can be used to identify the source object of an event?

getSource() Signup and view all the answers

Study Notes

JavaFX Event System

Root class for events is javafx.event.Event, a subclass of java.util.EventObject.
Subclasses of Event address various event types: action, window, mouse, and key events.
Nodes that can fire events mean their subclasses can also trigger the same event types.

Event Handling

Handler class must implement the specific event-handler interface corresponding to the event type.
JavaFX includes an EventHandler<T> interface containing the handle(T e) method for processing events.

Registration of Event Handlers

Event handlers must be registered with the source object using specific methods:
- setOnAction for action events.
- setOnMousePressed for mouse-pressed events.
- setOnKeyPressed for key-pressed events.

Class Structures

Inner Class: Defined within another class, allowing direct access to outer class data and methods.
Anonymous Inner Class: A nameless class defined at the point of instantiation, simplifying event handling code.
- Can leverage lambda expressions for functional interface handlers.

Interfaces and Events

Functional Interface: Contains exactly one abstract method, also referred to as Single Abstract Method (SAM) interface.
Key Event: Triggered by pressing, releasing, or typing keys; access key code using the getCode() method.
Mouse Event: Triggered by mouse actions; use getButton() to determine which mouse button was pressed.

Observable and Listeners

Observable objects can add listeners using addListener(InvalidationListener listener).
Listeners are notified upon property value changes, implementing the InvalidationListener interface to handle updates.

Animation in JavaFX

The abstract Animation class underpins JavaFX animation functions.
Specialized classes like PathTransition, FadeTransition, and Timeline implement specific animation behaviors.

Events and Programming Paradigms

Event: A signal indicating an occurrence, such as mouse input or keystrokes; programs can choose to respond or ignore.
Event-Driven Programming: User interactions drive program execution in Java GUI applications.
Event Object: Encapsulates relevant event properties; utilize getSource() in EventObject to identify the source of events.

Compiling Inner Classes

An anonymous inner class is compiled into a class named following the format OuterClassName$n.class.
Constructors for anonymous inner classes default to their superclass's no-arg constructor.

Description

Test your knowledge with these flashcards from Chapter 15 of Java FX. This chapter covers the fundamental concepts of event handling, including the root class for event classes and handler classes. Perfect for reviewing key terms and definitions related to Java FX events.