如何通过单击按钮更改标签文本?

Question

如果您回答，请张贴示例代码。我的代码是:

package Program;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Screen extends JFrame {
public Screen() {
setVisible(true);
setSize(600,400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
setAlwaysOnTop(true);

JPanel panel = new JPanel();
panel.setBackground(Color.BLACK);
panel.setLayout(null);
JLabel lbl = new JLabel();
lbl.setForeground(Color.green);
lbl.setBounds(300,100,60,60);
JButton btn1 = new JButton();
btn1.setText("Click");
btn1.setBackground(Color.MAGENTA);
btn1.setBounds(200,200,70,50);
btn1.addActionListener();
panel.add(btn1);
panel.add(lbl);
add(panel);
setContentPane(panel);

}
ActionListener kk = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
lbl.setText("blablabla, I know its local, but I don´t know how to fix it");
}
};
}

在我的Main方法/类中，我创建了一个这个类的对象，请帮助。我已经说过我知道它是本地的，但我不知道如何修复它。

Answer 1

您没有链接ActionListener对象和按钮。试试这个:

package Program;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class Screen extends JFrame {
public Screen() {
setVisible(true);
setSize(600,400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
setAlwaysOnTop(true);

JPanel panel = new JPanel();
panel.setBackground(Color.BLACK);
panel.setLayout(null);
JLabel lbl = new JLabel();
lbl.setForeground(Color.green);
lbl.setBounds(300,100,60,60);
JButton btn1 = new JButton();
btn1.setText("Click");
btn1.setBackground(Color.MAGENTA);
btn1.setBounds(200,200,70,50);
ActionListener kk = new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
lbl.setText("blablabla, I know its local, but I don´t know how 
to fix it");
}
};
btn1.addActionListener(kk);
panel.add(btn1);
panel.add(lbl);
add(panel);
setContentPane(panel);

}

}

:不久或

btn1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
lbl.setText("blablabla, I know its local, but I don´t know how 
to fix it");
}
});