问答题

本题中，主窗口有一个按钮“打开对话框”和一个文本域，单击按钮“打开对话框”后会弹出一个对话框，对话框上有两个按钮“Yes”和“No”，单击对话框上的“Yes”和“No”按钮后返回主窗口，并在右侧文本域中显示刚才所单击的按钮信息。
import java.awt.event.;
import java.awt.;
class MyDialogimplements ActionListener
static final int YES=1,NO=0;
int message=-1;Button yes,no;
MyDialog(Frame f,String s,boolean b)
super(f,s,b);
yes=new Button("Yes");yes.addActionListener(this);
no=new Button("No");no.addActionListener(this);
setLayout(new FlowLayout());
add(yes);add(no);
setBounds(60,60,100,100);
addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
message=-1;setVisible(false);
);
public void actionPerformed(ActionEvent e)
if(e.getSource()==yes)
message=YES;
setVisible(false);
else if(e.getSource()==no)
message=NO;
setVisible(false);

public int getMessage()
return message;

class Dwindow extends Frame implements ActionListener
TextArea text;Button button;MyDialog dialog;
Dwindow(String s)
super(s);
text=new TextArea(5,22);button=new Button("打开对话框");
button.addActionListener(this);
setLayout(new FlowLayout());
add(button);add(text);
dialog=new MyDialog(this,"Dialog",true);
setBounds(60,60,300,300);setVisible(true);
validate();
addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
(System.exit(0);
);
public void actionPerformed(ActionEvent e)
if(e.getSource()==button)
;
if(dialog.getMessage()==MyDialog.YES)
text.append("n你单击了对话框的yes按钮");
else if(dialog.getMessage()==MyDialog.NO)
text.append("\n你单击了对话框的No按钮");

public class java2
public static void main(String args[])
(new Dwindow("java2");

【参考答案】

第1处：extends Dialog
第2处：dialog.setVisible(true)

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