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【第18章：图形界面】_复选框：JCheckBox

发布时间：2021-01-18 14:37:45编辑：雪饮阅读（）

 复选框的实现

使用javax.swing.JcheckBox类可以实例化复选框组件
import java.awt.Container ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JPanel ;
import javax.swing.JCheckBox ;
import javax.swing.BorderFactory ;
class MyCheckBox{
       private JFrame frame = new JFrame("Welcome To kasumi") ;
       private Container cont = frame.getContentPane() ; // 得到窗体容器
       private JCheckBox jcb1 = new JCheckBox("kasumi") ;      // 定义一个复选框
       private JCheckBox jcb2 = new JCheckBox("snowDrink") ;
       private JCheckBox jcb3 = new JCheckBox("momiji") ;
       private JPanel pan = new JPanel() ;
       public MyCheckBox(){
              pan.setBorder(BorderFactory.createTitledBorder("请勾选喜欢的角色")) ;
              pan.setLayout(new GridLayout(1,3)) ;
              pan.add(this.jcb1) ;
              pan.add(this.jcb2) ;
              pan.add(this.jcb3) ;
              cont.add(pan) ;
              this.frame.setSize(330,80) ;
              this.frame.setVisible(true) ;
       }
 
}
public class Hello{
       public static void main(String args[]) throws Exception{
              new MyCheckBox() ;
       }
};

复选框事件监听
实现java.awt.event.ItemListener接口的itemStateChanged方法可以对复选框选择事件进行监听
import java.io.File ;
import java.awt.Container ;
import java.awt.GridLayout ;
import java.awt.event.ItemListener ;
import java.awt.event.ItemEvent ;
import javax.swing.JFrame ;
import javax.swing.ImageIcon ;
import javax.swing.JPanel ;
import javax.swing.JCheckBox ;
import javax.swing.BorderFactory ;
class MyItemListener implements ItemListener{
       private String right = "d:" + File.separator + "right.png" ;
       private String wrong = "d:" + File.separator + "wrong.gif" ;
       public void itemStateChanged(ItemEvent e){
              // 不管如何操作，则肯定由JCheckBox产生事件
              JCheckBox jcb = (JCheckBox)e.getItem() ; // 得到产生的事件
              if(jcb.isSelected()){ // 如果被选中了，则显示正确的图片
                     jcb.setIcon(new ImageIcon(right)) ;
              }else{
                     jcb.setIcon(new ImageIcon(wrong)) ;
              }
       }
}
class MyCheckBox{
       private String wrong = "d:" + File.separator + "wrong.gif" ;
       private JFrame frame = new JFrame("Welcome To kasumi") ;
       private Container cont = frame.getContentPane() ;
       private JCheckBox jcb1 = new JCheckBox("kasumi",new ImageIcon(wrong)) ;
       private JCheckBox jcb2 = new JCheckBox("snowDrink",new ImageIcon(wrong)) ;
       private JCheckBox jcb3 = new JCheckBox("ayane",new ImageIcon(wrong)) ;
       private JPanel pan = new JPanel() ;
       public MyCheckBox(){
              pan.setBorder(BorderFactory.createTitledBorder("请选择喜欢的角色")) ;
              pan.setLayout(new GridLayout(1,3)) ;
              pan.add(this.jcb1) ;
              pan.add(this.jcb2) ;
              pan.add(this.jcb3) ;
              //监听每个复选框的选择事件
              jcb1.addItemListener(new MyItemListener()) ;
              jcb2.addItemListener(new MyItemListener()) ;
              jcb3.addItemListener(new MyItemListener()) ;
 
              cont.add(pan) ;
              this.frame.setSize(330,80) ;
              this.frame.setVisible(true) ;
       }
 
}
public class Hello{
       public static void main(String args[]) throws Exception{
              new MyCheckBox() ;
       }
};