我很好奇为什么在 JLayeredPane 上调用 setBackground(Color) 似乎并没有真正设置背景颜色。我想这与 JLayeredPane 出于某种原因必须具有透明背景有关吗?无论如何,这里有一些显示问题的代码。这是在 Mac 上,所以我相信它使用的是 OSX LAF。此图像显示了由此产生的结果。
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
public class Main {
public static void main(String[] args) {
// This should be done with Swing Utilities, but I wanted to keep this
// simple...
JFrame foo = new JFrame();
foo.setSize(new Dimension(500, 500));
JLayeredPane bar = new JLayeredPane();
bar.setPreferredSize(new Dimension(200, 200));
bar.setBackground(Color.red);
// If you comment out the following line, you don't see any indication
// the JLayeredPane is actually being drawn to screen
bar.setBorder(BorderFactory.createLineBorder(Color.green));
JPanel content = new JPanel();
content.add(bar);
foo.setContentPane(content);
foo.setVisible(true);
}
}