JLabel默认是透明的,所以JLabel设置背景色setBackground之前要setOpaque(true);
将不透明设为true,再setBackground
jlabel.setOpaque(true); jlabel.setBackground(new Color(0, 0, 0, 100));
//将不透明设为true,再setBackgroundjlabel.setOpaque(true); jlabel.setBackground(new Color(0, 0, 0, 100));
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.*;
import javax.swing.*;public class JLabel默认是透明的_所以JLabel设置背景色setBackground之前要setOpaque为true {public static void main(String...arguments)throws Exception{JFrame frame = new JFrame(Thread.currentThread().getStackTrace()[1].getClassName());frame.addWindowListener(new WindowAdapter() {@Overridepublic void windowClosing(WindowEvent windowEvent) {System.out.println(windowEvent);System.exit(0);}});frame.setBounds(100, 100, 1024, 768);JLabel jlabel = new JLabel("""<html><head></head><body><div style='background:rgba(100,100,255,0.5); text-align:center;'>JLabel默认是透明的_所以JLabel设置背景色setBackground之前要setOpaque为true<br/>//将不透明设为true,再setBackground<br/>label.setOpaque(true); jlabel.setBackground(new Color(0, 0, 0, 200));JLabel中的html的背景色不会覆盖整个JLable, html的background在JLabel的background之上</div></body></html>""");frame.add(jlabel);//将不透明设为true,再setBackgroundjlabel.setOpaque(true); jlabel.setBackground(new Color(0, 0, 0, 100));frame.setVisible(true);}}
