将面板添加到JFrame

Question

代码中没有错误，但我似乎无法在窗口中看到Jlabels。我不确定是否添加了面板或是否将jlabels添加到面板中。

public class JDemoResistance extends JFrame{

    private final JButton button1;
    private JPanel panel;
    private final int WINDOW_WIDTH = 320;
    private final int WINDOW_HEIGHT = 320;

    public JDemoResistance() {
        super("JDemoResistance");

        setSize(WINDOW_WIDTH, WINDOW_HEIGHT);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //JLabels Configs
        JLabel label1 = new JLabel("Too expensive");
        JLabel label2 = new JLabel("Bad reviews");
        JLabel label3 = new JLabel("Bad quality");
        JLabel label4 = new JLabel("Not worth it");
        JLabel label5 = new JLabel("Dosent work");

        //Button Configs
        button1 = new JButton("Button");
        button1.addActionListener(new ButtonListener());

        //Panel Configs
        panel = new JPanel();
        panel.add(label1);
        panel.add(label2);
        panel.add(label3);
        panel.add(label4);
        panel.add(label5);
        panel.add(button1);
        setVisible(true);
    }

      private class ButtonListener implements ActionListener {
        @Override
        public void actionPerformed(ActionEvent e){

        }
    }      

    public static void main(String[] args) {
        JDemoResistance jdr = new JDemoResistance();

    }


}

Answer 1

您尚未将面板添加到框架中，这就是您无法看到任何组件的原因。在设置JFrame可见之前添加它。

 //Add the panel to the frame
 this.add(panel)
 setVisible(true);

Answer 2

您也必须将面板添加到JFrame。

panel.add(...);
add(panel); // <-- you forgot this
setVisible(true);