java的复选框[Java编程]

//: CheckBox1.java
// Using check boxes
import java.awt.*;
import java.applet.*;

public class CheckBox1 extends Applet {
  TextArea t = new TextArea(6, 20);
  Checkbox cb1 = new Checkbox("Check Box 1");
  Checkbox cb2 = new Checkbox("Check Box 2");
  Checkbox cb3 = new Checkbox("Check Box 3");
  public void init() {
    add(t); add(cb1); add(cb2); add(cb3);
  }
  public boolean action (Event evt, Object arg) {
    if(evt.target.equals(cb1))
      trace("1", cb1.getState());
    else if(evt.target.equals(cb2))
      trace("2", cb2.getState());
    else if(evt.target.equals(cb3))
      trace("3", cb3.getState());
    else 
      return super.action(evt, arg);
    return true;
  }
  void trace(String b, boolean state) {
    if(state)
      t.appendText("Box " + b + " Set\n");
    else
      t.appendText("Box " + b + " Cleared\n");
  }
} ///:~