checkboxes.java

Thinking in JAVA第四版源代码

//: gui/CheckBoxes.java
// Using JCheckBoxes.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import static net.mindview.util.SwingConsole.*;

public class CheckBoxes extends JFrame {
  private JTextArea t = new JTextArea(6, 15);
  private JCheckBox
    cb1 = new JCheckBox("Check Box 1"),
    cb2 = new JCheckBox("Check Box 2"),
    cb3 = new JCheckBox("Check Box 3");
  public CheckBoxes() {
    cb1.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        trace("1", cb1);
      }
    });
    cb2.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        trace("2", cb2);
      }
    });
    cb3.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent e) {
        trace("3", cb3);
      }
    });
    setLayout(new FlowLayout());
    add(new JScrollPane(t));
    add(cb1);
    add(cb2);
    add(cb3);
  }
  private void trace(String b, JCheckBox cb) {
    if(cb.isSelected())
      t.append("Box " + b + " Set\n");
    else
      t.append("Box " + b + " Cleared\n");
  }
  public static void main(String[] args) {
    run(new CheckBoxes(), 200, 300);
  }
} ///:~