topdialogdemo.java

java2应用开发指南第一版

//TopDialogDemo.java
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class TopDialogDemo extends JApplet
{
	JDialog dlg;
	
	public void init()
	{
		JButton btnShowDialog=new JButton("显示对话框");
		btnShowDialog.addActionListener(new ActionListener(){
			public void actionPerformed(ActionEvent e)
			{
				if( dlg == null )
					dlg=new JDialog(getTopFrame(),"这是个总是显示前面的对话框",false);
				dlg.setSize(new Dimension(300,200));
				dlg.show();
			}
		});
		
		this.getContentPane().add(btnShowDialog);
	}
	
	public Frame getTopFrame() 
	{
          //if(topFrame!=null) return topFrame;

          Container parent;
          for(parent = this; parent != null && !(parent instanceof Frame) ; parent = parent.getParent());
          if(parent != null)
    	    return (Frame)parent;
          else
    	    return null;
  	}
}