Prentice.Hall.Introduction.to.Java.Programming,.Brief.Version.9th.(2014).[sharethefiles.com]

496 Chapter 13 Graphics
add message panel
18 messagePanel1.setCentered(true);
19
20 setLayout(new GridLayout(2, 2));
21 add(messagePanel1);
22 add(messagePanel2);
23 add(messagePanel3);
24 add(messagePanel4);
25 }
26
27 public static void main(String[] args) {
28 TestMessagePanel frame = new TestMessagePanel();
29 frame.setSize(300, 200);
30 frame.setTitle("TestMessagePanel");
31 frame.setLocationRelativeTo(null); // Center the frame
32 frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
33 frame.setVisible(true);
34 }
35 }
javax.swing.JPanel
MessagePanel
The get and set methods for these
data fields are provided in the class, but
omitted in the UML diagram for brevity.
-xCoordinate: int
-yCoordinate: int
-centered: boolean
-message: String
-interval: int
The x-coordinate for the message.
The y-coordinate for the message.
Specifies whether the message is displayed centered.
The message to be displayed.
The interval to move the message in the panel.
+MessagePanel()
+MessagePanel(message: String)
+moveLeft(): void
+moveRight(): void
+moveUp(): void
+moveDown(): void
Constructs a default message panel.
Constructs a message panel with a specified string.
Moves the message to the left.
Moves the message to the right.
Moves the message up.
Moves the message down.
FIGURE 13.18
MessagePanel displays a message on the panel.
FIGURE 13.19
TestMessagePanel uses MessagePanel to display four message panels.
skip implementation?
The rest of this section explains how to implement the MessagePanel class. Since you can
use the class without knowing how it is implemented, you may skip the implementation if
you wish.