Question

我想在swing中一个BorderLayout布局中的north板块加入JPanel面板，显示文字，但无法显示，代码如下

main.java
public class Main {

public static void main(String[] args) {
MainFrame f = new MainFrame();
f.setVisible(true);
}
}
MainFrame.java

public class MainFrame extends JFrame {

private static final long serialVersionUID = 1L;
static int WIDTH = 800;
static int HEIGHT = 600;

CentralController centralController;
UserBar user;
DownloaderMenuBar menuBar;//菜单项

public MainFrame() {
this.setTitle("下载器");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Toolkit toolkit = Toolkit.getDefaultToolkit();
Dimension screenSize = toolkit.getScreenSize();
int x = screenSize.width / 2 - WIDTH / 2;
int y = screenSize.height / 2 - HEIGHT / 2;
this.setBounds(x, y, WIDTH, HEIGHT);
init();
}

private void init() {
this.setLayout(new BorderLayout());
user = new UserBar();
this.add(user,"North");
}
}
userBar.java

public class UserBar extends JLabel{
private static final long serialVersionUID = 1L;

CentralController centralController;
JPanel panel;
public UserBar(){
init();
}

private void init(){
JPanel panel = new JPanel();
panel.setLayout(null);
panel.setBounds(0,0,200,150);
panel.setBackground(Color.CYAN);
JLabel label1 = new JLabel();
label1.setBounds(10, 10, 30, 30);
panel.add(label1);
this.add(panel);
label1.setVisible(true);
this.setBorder(BorderFactory.createEtchedBorder(0));
}
}

Answer 1

呵呵 你那个JFrame初始化方法里面没有setVisible(true);

追问

main 方法里不是有f.setVisible(true);了吗