我很好奇在JLayeredPane上调用setBackground(Color)为什么似乎没有真正设置背景颜色。我猜测这可能与JLayeredPane必须有透明背景有关?无论如何,这是一些显示问题的代码。这在Mac上运行,所以我认为它使用的是OSX LAF。这个代码产生的结果由这张图片显示。
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);
}
}