向JFrame添加面板

Question

代码中没有错误，但我似乎看不到窗口中的Jlabels。我不确定是否添加了面板，或者是否将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

您还没有将面板添加到框架中，这就是为什么您看不到任何组件。在设置JFrame可见之前添加它。

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

Answer 2

您必须将面板添加到JFrame。

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