求教！！！

Question

import java.awt.*;
import java.awt.event.*;public class DialogTest extends Frame {
    private Dialog d;
    
    private Dialog sd;
    public DialogTest() {
        Button b;
        setBounds(100, 100, 600, 400);
        b = new Button("NEW");
        d = new Dialog(this, "NEW"); //无模式的 Dialog
        d.setBounds(150, 150, 300, 200);
        b.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                d.setVisible(true);
            }
        });
        d.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                d.setVisible(false);
            }
        });
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        add("South", b);
        
        Button ko;
        ko = new Button("ohayo");
        sd = new Dialog(d,"ohayo");
        sd.setBounds(50,50,100,100);
        ko.addActionListener(new ActionListener() {
            public void actionPerormed(ActionEvent e) {
                sd.setVisible(true);
            }            public void actionPerformed(ActionEvent e) {}
        });
        sd.add("South",d);
        setVisible(true);
    }    public static void main(String[] args) {
        new DialogTest();
    }
}为什么 add 不上了？

Answer 1

应该调用一下layout或者repait等函数吧

Answer 2

import java.awt.*; 
import java.awt.event.*; public class DialogTest extends Frame { 
    private Dialog d; 
    private Dialog sd;
    
    public DialogTest() { 
        Button b; 
        setBounds(100, 100, 600, 400); 
        b = new Button("NEW"); 
        d = new Dialog(this, "NEW"); //无模式的 Dialog 
        d.setBounds(150, 150, 300, 200); 
        b.addActionListener(new ActionListener() { 
            public void actionPerformed(ActionEvent e) { 
                d.setVisible(true); 
            } 
        }); 
        d.addWindowListener(new WindowAdapter() { 
            public void windowClosing(WindowEvent e) { 
                d.setVisible(false); 
            } 
        }); 
        addWindowListener(new WindowAdapter() { 
            public void windowClosing(WindowEvent e) { 
                System.exit(0); 
            } 
        }); 
        add("South", b); 
         
        Button ko; 
        ko = new Button("ohayo");
        
        sd = new Dialog(d,"ohayo"); 
        sd.setBounds(50,50,100,100);
        
        //需要添加ko的监听事件
        ko.addActionListener(new ActionListener() { 
public void actionPerformed(ActionEvent e) {
sd.setVisible(true);//显示第二个Dialog,既sd
} 
        });
        sd.addWindowListener(new WindowAdapter() { 
            public void windowClosing(WindowEvent e) { 
                sd.setVisible(false); 
            } 
        }); 
        //KO按钮是添加到第一个Dialog里的
        d.add("South",ko); 
        setVisible(true); 
    }     public static void main(String[] args) { 
        new DialogTest(); 
    } 
} 
按钮放置的层次弄混了,所以即便添加了按钮也不会有显示的!