关于背景色的设置 this.setBackground(Color.black); 这样似乎没效果
import java.awt.*;
import javax.swing.*;
import java.awt.geom.*;
public class Draw_tendency extends JPanel{
//构造函数
public Draw_tendency() {
super();
//使部件变得透明
setOpaque(true);
//setLayout(new BorderLayout());
setBorder(BorderFactory.createLineBorder(Color.black));
setBackground(Color.blue);
}
protected void paintComponent(Graphics g) {
int i =10;
for (int j = 0; j < 20; j++) {
Color c = new Color( (int) (Math.random() * 0xffffff));
g.setColor(c);
g.drawString("i am a boy!", 50 + i, 50 + i);
i += 20;
}
}
}
我想把背景色设置成黑色的,可是不成功~`
如何解决?