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编程包含一个标签和一个按钮,单击按钮时,标签的内容在"你好"和"再见"之间切换。
package exercise;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class changeGUI extends JFrame{
private JButton button;
private JLabel label;
public changeGUI() {
super();
JPanel jPanel=new JPanel();
JPanel jPanel2=new JPanel();
setLayout(new GridLayout(2,1));
button=new JButton("切换");
button.setBackground(Color.gray);
button.setForeground(Color.RED);
jPanel.add(button);
button.addActionListener(new changeActionListener());
label=new JLabel("你好");
label.setForeground(Color.BLUE);
jPanel2.add(label);
add(jPanel2);
add(jPanel);
}
private class changeActionListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
if(label.getText()=="你好") {
label.setText("再见");
}else {
label.setText("你好");
}
}
}
public static void main(String[] args) {
changeGUI change=new changeGUI();
change.setSize(300,200);
change.setVisible(true);
change.setLocationRelativeTo(null);
change.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
运行结果如下:
经过测试,可以放心使用