EVENT-DRIVEN PROGRAMMING AND ANIMATIONS - Introduction to Java Programming: Comprehensive Version - page 604

key-released events, getCode() returns the value as defined in the table, getText() returns
a string that describes the key code, and getCharacter() returns an empty string. For the
key-typed event, getCode() returns UNDEFINED and getCharacter() returns the Unicode
character or a sequence of characters associated with the key-typed event.

key code

T ABLE 15.2 KeyCode Constants

Constant Description Constant Description

HOME The Home key

CONTROL The Control key

The End key

END SHIFT The Shift key

PAGE_UP The Page Up key BACK_SPACE The Backspace key

PAGE_DOWN The Page Down key The Caps Lock key

CAPS

UP The up-arrow key

NUM_LOCK The Num Lock key

The down-arrow key

DOWN ENTER The Enter key

LEFT The left-arrow key UNDEFINED The keyCode unknown

RIGHT The right-arrow key

F1 to F12

The function keys from F1 to F12

ESCAPE The Esc key

0 to 9 The number keys from 0 to 9

The Tab key

TAB A to Z The letter keys from A to Z

The program in Listing 15.8 displays a user-input character. The user can move the char-
acter up, down, left, and right, using the up, down, left, and right arrow keys. Figure 15.13
contains a sample run of the program.

F IGURE 15.13

The program responds to key events by displaying a character and moving it
up, down, left, or right.

L ISTING 15.8

KeyEventDemo.java
1 import javafx.application.Application;
2 import javafx.scene.Scene;
3 import javafx.scene.layout.Pane;
4 import javafx.scene.text.Text;
5 import javafx.stage.Stage;
6
7 public class KeyEventDemo extends Application {
8 @Override // Override the start method in the Application class
9 public void start(Stage primaryStage) {
10 // Create a pane and set its properties
11 Pane pane = new Pane();
12 Text text = new Text( 20 , 20 , "A" );
13
14 pane.getChildren().add(text);
15 text.setOnKeyPressed(e -> {
16

create a pane

register handler
get the key pressed
move a character

switch (e.getCode()) {

17 case DOWN: text.setY(text.getY() + 10 ); break ;

18 case UP: text.setY(text.getY() - 10 ); break ;

19 case LEFT: text.setX(text.getX() - 10 ); break ;

20 case RIGHT: text.setX(text.getX() + 10 ); break ;