EVENT-DRIVEN PROGRAMMING AND ANIMATIONS - Introduction to Java Programming: Comprehensive Version - page 603

4 import javafx.scene.text.Text;
5 import javafx.stage.Stage;
6
7 public class MouseEventDemo 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 , "Programming is fun" );
13 pane.getChildren().addAll(text);
14

create a pane
create a text
add text to a pane
lambda handler
reset text position

text.setOnMouseDragged(e -> {

15 text.setX(e.getX());

16 text.setY(e.getY());

17 });

18
19 // Create a scene and place it in the stage
20 Scene scene = new Scene(pane, 300 , 100 );
21 primaryStage.setTitle( "MouseEventDemo" ); // Set the stage title
22 primaryStage.setScene(scene); // Place the scene in the stage
23 primaryStage.show(); // Display the stage
24 }
25 }

Each node or scene can fire mouse events. The program creates a Text (line 12) and registers
a handler to handle move dragged event (line 14). Whenever a mouse is dragged, the text's
x - and y -coordinates are set to the mouse position (lines 15 and 16).

15.14

✓ ✓

What method do you use to get the mouse-point position for a mouse event?

Check

15.15

What methods do you use to register a handler for a mouse pressed, released, clicked,
entered, exited, moved and dragged event?

Point

15.9 Key Events
A KeyEvent is fired whenever a key is pressed, released, or typed on a node or a scene.
Key events enable the use of the keys to control and perform actions or get input from the
keyboard. The KeyEvent object describes the nature of the event (namely, that a key has been
pressed, released, or typed) and the value of the key, as shown in Figure 15.12.

Key
Point

javafx.scene.input.KeyEvent

+getCharacter(): String
+getCode(): KeyCode
+getText(): String
+isAltDown(): boolean
+isControlDown(): boolean
+isMetaDown(): boolean
+isShiftDown(): boolean

Returns the character associated with the key in this event.
Returns the key code associated with the key in this event.
Returns a string describing the key code.
Returns true if the Alt key is pressed on this event.
Returns true if the Control key is pressed on this event.
Returns true if the mouse Meta button is pressed on this event.
Returns true if the Shift key is pressed on this event.

F IGURE 15.12

The KeyEvent class encapsulates information about key events.

Every key event has an associated code that is returned by the getCode() method in
KeyEvent . The key codes are constants defined in KeyCode . Table 15.2 lists some constants.
KeyCode is an enum type. For use of enum types, see Appendix I. For the key-pressed and