public class HelloGUIApp4
1: //HelloGUIApp4.java
2: //An application to display "Hello, world!" in a window,
3: //and this time it's a window that will close, either by
4: //clicking on the window's close box or by clicking on
5: //the Quit button of the application. In addition, the
6: //button is in color, and the window size should be
7: //changed by the user after it opens to see how the
8: //"flow layout" adjusts the positions of the button
9: //and label. Compare this with the fixed position of
10: //the other text.
12: import java.awt.*;
13: import java.awt.event.*;
15: public class HelloGUIApp4
16: extends Frame
17: implements ActionListener, WindowListener
18: {
19: private Button button;
20: private Label label;
22: public static void main(String[] args)
23: {
24: HelloGUIApp4 application = new HelloGUIApp4();
25: application.setSize(100, 100);
26: application.setVisible(true);
27: }
30: public HelloGUIApp4()
31: {
32: setTitle("Hello with Quit Button");
34: setLayout(new FlowLayout());
36: button = new Button("Quit");
37: button.setBackground(Color.yellow);
38: add(button);
39: button.addActionListener(this);
41: label = new Label("Hello, world!");
42: add(label);
44: addWindowListener(this);
45: }
48: public void actionPerformed(ActionEvent event)
49: {
50: System.exit(0);
51: }
53:
54: public void windowClosed(WindowEvent event) {}
55: public void windowDeiconified(WindowEvent event) {}
56: public void windowIconified(WindowEvent event) {}
57: public void windowActivated(WindowEvent event) {}
58: public void windowDeactivated(WindowEvent event) {}
59: public void windowOpened(WindowEvent event) {}
60: public void windowClosing(WindowEvent event)
61: {
62: System.exit(0);
63: }
66: //Try commenting out this method.
67: public void paint(Graphics g)
68: {
69: g.drawString("Hello, world!", 20, 90);
70: }
71: }