称为面板的 JPanel 仅显示为顶部中心上方的一个红色小方块,我试图设置大小,但它似乎没有做任何事情。
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Draw extends JFrame{
private JPanel panel;
public Draw() {
super("title");
setLayout(new FlowLayout());
panel = new JPanel();
panel.setBackground(Color.RED);
add(panel, BorderLayout.CENTER);
}
}