testcheck.java

非常好的JAVA学习资料

package textareacheckbox;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
public class TestCheck extends Applet {
  TextArea ta1=new TextArea("show result",5,10);  //用文本区域显示选择结果
  Checkbox ck1=new Checkbox("one",true);
  Checkbox ck2=new Checkbox("two",false);
  Checkbox ck3=new Checkbox("three",true);       //one, two, three为复选框
  CheckboxGroup cg=new CheckboxGroup();
  Checkbox ck4=new Checkbox("four",true,cg);
  Checkbox ck5=new Checkbox("five",false,cg);
  Checkbox ck6=new Checkbox("six",false,cg);     // four, five, six为单选钮

class CheckListener implements ItemListener{    //定义CheckListener类监听选项事件
      public void itemStateChanged(ItemEvent e) {
/*Object source=e.getSource();  
        if ( source = = ck1 )  …
        else if ( source = = ck2 )  …*/
        String source=(String)(e.getItem());      //用getItem( )取的事件源，见表5.2.8
        if ( source == "one" ){                 //若事件源是复选框one
          if ( e.getStateChange() == e.SELECTED ) { 
//是选择还是去掉选择，getStateChange()见表5.2.8          
            ta1.setText("one selected"); 
//若是选择则在文本区域中显示“one selected”
          }
          else ta1.setText("one deselected");
//若是去掉选择则在文本区域中显示“one deselected”
        }
        else if ( source == "two" ) {
          if ( e.getStateChange() == e.SELECTED ){
            ta1.setText("two selected");
          }
          else ta1.setText("two deselected");
        }
        else if ( source == "three" ){
          if ( e.getStateChange() == e.SELECTED ){
            ta1.setText("three selected");
          }
          else ta1.setText("three deselected");
        }
        if ( source == "four" ){
          if ( e.getStateChange() == e.SELECTED ){
            ta1.setText("four selected");
          }
        }
        if ( source == "five" ){
          if ( e.getStateChange() == e.SELECTED ){
            ta1.setText("five selected");
          }
        }
        if ( source == "six" ){
          if ( e.getStateChange() == e.SELECTED ) {
            ta1.setText("six selected");
          }
        }
      }
  }
  public void init() {
  add(ta1);  add(ck1);  add(ck2);  add(ck3);  add(ck4);  add(ck5);
  add(ck6);                //将各组件显示在小应用程序的显示区域中
  ck1.addItemListener(new CheckListener ());              //设置监听者
  ck2.addItemListener(new CheckListener ());
  ck3.addItemListener(new CheckListener ());
  ck4.addItemListener(new CheckListener ());
  ck5.addItemListener(new CheckListener ());
  ck6.addItemListener(new CheckListener ());
  }
}