Question

java：点击按钮，改变label的文字！！！

怎样添加命令？import java.awt.*;import javax.swing.*;import java.awt.event.*;public class haibao extends JPanel implements ActionListener{ JFrame frame; int tag = 0; public static void main (String [ ] args){ haibao gui = new haibao(); gui.go(); } public void go(){ frame = new JFrame(); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JButton button = new JButton("换一张！"); frame.getContentPane().add(button,"South"); JLabel label1 = new JLabel("电影海报"); frame.getContentPane().add(label1, "North"); JLabel label2 = new JLabel("换一张"); frame.getContentPane().add(label2, "North"); frame.getContentPane().add(new haibao()); frame.setSize(1024, 576); frame.setVisible(true); } public void actionPerformed(ActionEvent event){ } public haibao(){ ImageIcon img = new ImageIcon("D:\\eclipse3\\works\\haibao\\src\\luhan.jpg"); JLabel jl = new JLabel(img); this.setLayout(new BorderLayout()); this.add(jl,BorderLayout.CENTER); } public void windowClosing(WindowEvent e){ System.exit(0); }}

Answer 1