CardLayout布局练习（小的图片浏览器）

 /*

 涉及Panel中的图片的加载，还有Frame的关闭的方法， CardLayout（int hgap, int vgap）就会决定卡片面板的大小

 匿名类的使用。。。

 */

 import java.awt.*;

 import java.awt.event.*;

 import javax.swing.*;

 public class CardLayoutDemo extends Frame{

    Panel pCards=new Panel();//卡片面板

    CardLayout Clayout=new CardLayout(120, 50);//设置卡片和面板边界的垂直和水平距离

    public CardLayoutDemo(){

          setLayout(new BorderLayout(100, 20));

          Panel pBtn = new Panel();//按钮面板

            pCards.setLayout(Clayout);

            //pCards.setPreferredSize(new Dimension(30,40));//这句不再起作用了：因为其父类CardLayoutDemo使用的是BorderLayout布局方式，会自动填充

            pCards.setBackground(Color.red);

            pBtn.setBackground(Color.yellow);

        pBtn.setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));

            pBtn.setPreferredSize(new Dimension(200, 50));

           Button tmpB;

        pBtn.add(tmpB = new Button("第一张"));

              tmpB.addActionListener(new myActionListener());

                tmpB.setActionCommand("first");

        pBtn.add(tmpB = new Button("下一张"));

              tmpB.addActionListener(new myActionListener());

                tmpB.setActionCommand("next");

        pBtn.add(tmpB = new Button("前一张"));

              tmpB.addActionListener(new myActionListener());

                tmpB.setActionCommand("previous");

        pBtn.add(tmpB = new Button("最后一张"));

              tmpB.addActionListener(new myActionListener());

                tmpB.setActionCommand("last");

        for(int i=1; i<=4; ++i){

               myPanel tmpP;

             pCards.add(""+i, tmpP=new myPanel(i){

                   public void paint(Graphics g){

               g.drawImage(new ImageIcon("zjy"+i+".jpg").getImage(), 20, 0, 300, 400, this);

              }

             });

               tmpP.setBackground(Color.blue);

               //tmpP.setSize(new Dimension(300, 400));//tmpP接受了匿名类对象，可以通过这种方法更改匿名类的属性

               //这里不设置的原因是它的大小由CardLayout(int hgap, int vgap)决定了

          }

            add(pBtn, "North");

            add(pCards, "Center");

    }

    class myActionListener implements ActionListener{

     public void actionPerformed(ActionEvent e){

        String str=e.getActionCommand();

        if(str.equals("first"))

            Clayout.first(pCards);

         else if(str.equals("next"))

            Clayout.next(pCards);

         else if(str.equals("previous"))

            Clayout.previous(pCards);

         else if(str.equals("last"))

            Clayout.last(pCards);

        }

     }

     public static void main(String args[]){

        CardLayoutDemo myWindow = new CardLayoutDemo();

        myWindow.setSize(new Dimension(600, 600));

        myWindow.setResizable(false);

        myWindow.addWindowListener(new myClosingListener());

        myWindow.setVisible(true);

     }

 }

 class myClosingListener extends WindowAdapter{

    public void windowClosing(WindowEvent e){

       System.exit(0);

    }

 }

 class myPanel extends Panel{

    int i;

    public myPanel(int i){

       this.i=i;

    }

 }