Java.布局管理器.CardLayout-GridLayout

//TestCardLayout.java package myprojects.testcardlayout; import java.awt.*; import java.awt.event.*; class TestCardLayout extends Frame { CardLayout cl=new CardLayout(); Panel plCenter=new Panel(); public TestCardLayout() { Panel plWest=new Panel(); plWest.setLayout(new GridLayout(3,1)); Button btnPrev=new Button("Prev"); Button btnNext=new Button("Next"); Button btnThree=new Button("Three"); plWest.add(btnPrev); plWest.add(btnNext); plWest.add(btnThree); add(plWest,"West"); plCenter.setLayout(cl); plCenter.add(new Button("one"),"1"); plCenter.add(new Button("two"),"2"); plCenter.add(new Button("three"),"3"); plCenter.add(new Button("four"),"4"); plCenter.add(new Button("five"),"5"); add(plCenter); class MyActionListener implements ActionListener{ public void actionPerformed(ActionEvent e){ if(e.getActionCommand().equals("Prev")){ cl.previous(plCenter); } else if(e.getActionCommand().equals("Next")){ cl.next(plCenter); } else{ cl.show(plCenter,"3"); } } } MyActionListener ma=new MyActionListener(); btnPrev.addActionListener(ma); btnNext.addActionListener(ma); btnThree.addActionListener(ma); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { dispose(); System.exit(0); } }); } public static void main(String args[]) { System.out.println("Starting TestCardLayout..."); TestCardLayout mainFrame = new TestCardLayout(); mainFrame.setSize(400, 400); mainFrame.setTitle("TestCardLayout"); mainFrame.setVisible(true); } }