将事件侦听器添加到JFrame

Question

我正在尝试将事件监听器添加到我的“播放”按钮，但每当我在播放按钮中添加一个按钮消失或我得到并且错误时。

package hamster.race;
import java.awt.*;
import javax.swing.*;

public class HamsterRace extends JFrame {
    public HamsterRace(){
        super("HamsterRace");
        setLookAndFeel();
        setSize(350*3, 100*5);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        FlowLayout flo = new FlowLayout();
        setLayout(flo);
        setVisible(true);
        JButton Play = new JButton("Play");
        add(Play);
        add(Play);


    }
    private void setLookAndFeel() {
        try{
           UIManager.setLookAndFeel{
                "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"
        };
        }catch (Exception exc) {
            //ignore error
        }
    }

    public static void main(String[] args) {
        HamsterRace frame = new HamsterRace();


    }

}

Answer 1

首先，变量名不应以大写字母开头。

    JButton Play = new JButton("Play");
    add(Play);
    add(Play);

您只有一个组件。您不能两次添加相同的组件。

所以基本代码是：

    //setVisible(true);
    JButton play1 = new JButton("Play1");
    add(play1);
    JButton play2 = new JButton("Play2");
    add(play2);
    pack();
    setVisible(true);