java - 如何在 JFrame 中显示 JButton 和 JLabels？

Question

我尝试使用此代码来显示带标签的窗口，但它只显示一个空白窗口。

    JFrame window = new JFrame("My Window");
    window.setVisible(true);
    window.setResizable(true);
    window.setSize(680,420);
    window.setContentPane(new Container());
    window.getContentPane().setLayout(new FlowLayout());
    JPanel panel = new JPanel();
    JLabel label = new JLabel("LABEL");
    label.setBackground(Color.BLACK);
    panel.add(label);
    window.add(panel);

Answer 1

尝试最后调用setVisible

JFrame window = new JFrame("My Window");
//window.setVisible(true);
//window.setResizable(true);
//window.setSize(680,420);
//window.setContentPane(new Container());
window.setLayout(new FlowLayout());
JPanel panel = new JPanel();
JLabel label = new JLabel("LABEL");
label.setBackground(Color.BLACK);
panel.add(label);
window.add(panel);

window.setResizable(true);
// Pack will size the window to fit the content, 
// tacking into account the preferred size of the
// content...
window.pack();
window.setVisible(true);

另请注意，JLabel 默认情况下是透明的，因此设置其背景颜色不会产生任何效果，除非将其 opaque 属性更改为 true