BorderLayout布局的JPanel为什么不能多次“嵌套”?求高手指点
public class Test extends JFrame{
private BorderLayout borderLayout = new BorderLayout(5,0);
private JPanel p1 = new JPanel();
private JPanel p2 = new JPanel();
public Test() {
this.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
this.p1.setLayout(borderLayout);
this.p2.setLayout(borderLayout);
this.p1.add(new JButton("RRRR"),BorderLayout.NORTH);
this.p1.add(new JButton("qqqq"),BorderLayout.CENTER);
this.p1.add(new JButton("www"),BorderLayout.SOUTH);
this.p2.add(p1,BorderLayout.NORTH);
this.add(p2);
this.setSize (400,600);
this.setVisible(true);
}
public static void main(String[] args){
Test t = new Test();
}
}