Question

我在Java中创建了一个简单的程序，我希望在单击“restart”numClick时将JMenuItem变量值设置为0。我现在所拥有的并没有改变任何事情。

代码：

public class Tests {

    JButton b1 = new JButton("Click Me");
    public int numClick = 0;
    JLabel l1 = new JLabel("You have clicked the button 0 times");

    public Tests() {
        frame();
    }

    public void frame() {
        JFrame f = new JFrame();
        f.setVisible(true);
        f.setSize(500,500);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel p = new JPanel();
        JMenuBar mb = new JMenuBar();
        JMenu file = new JMenu("File");
        JMenuItem exit = new JMenuItem("Exit");
        JMenuItem restart = new JMenuItem("Restart");
        p.add(b1);
        p.add(l1);  
        mb.add(file);
        file.add(exit);
        file.add(restart);
        f.add(p);
        f.setJMenuBar(mb);

        exit.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });

        restart.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                numClick = 0;
            }
        });

        b1.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e) {
                numClick++;
                l1.setText("You have clicked the button " + numClick + " times");
            }
        });
    }

    public static void main(String[] args) {
        new Tests();
    }
}

Answer 1

只需更新重启动作监听器中的文本

restart.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        numClick = 0;
        l1.setText("You have clicked the button " + numClick + " times");
    }
});

Answer 2

看来你已经快到了。在将numClick设置为0之后，只需在重启的ActionListener actionPerformed方法中添加行l1.setText("You have clicked the button " + numClick + " times");。就是这样。

restart.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent e)
    {
        numClick = 0;

        // simply add this line, that's it.
        l1.setText("You have clicked the button " + numClick + " times");
    }
});

单击Button时更改int的值

2 个答案: