Displaying TOOL TIP message over an applet

Question

Hi,
How to display a tooltip(hint) like message when the mouse moves over an applet. Here is the rough source code, Please do the needful.
import java.applet.*;
import java.awt.*;
public class Dis extends Applet implements MouseListner
     public void init()
          setLayout(null);
          ButtonAb b = new ButtonAb("click me"); //this is another class that is being called here, this class extends Component, I have written all ActionListeners and MouseListeners in this class only
          b.add();
     //public void addMouseListener(MouseEvent me)
When the mouse moves over the Button("click me"), a hint box or tooltip like message should be displayed. It is easy doing with VB or Swing, but I wanted to it with AWT. Please give me some source code also.
Thanks in advance
Uma

Answer 1

There are several ways to implement tooltip in awt. I prefere a general ToolTip class that can be added to any Component, and that is easy to use:
something like this:Button but;
but = new Button("Push");
add(but);
new ToolTip(but, "Push this button if you want to push this button");The code above should add a ToolTip to the java.awt.Button, so that everytime the mouse hoovers over the button, the message gets displayed.
The idea is to make a ToolTip that can be added to any java.awt.Component using one line of code only. How do one achive that? Ok, here is a pseudo implementation of the ToolTip class:class ToolTip extends java.awt.Canvas implements Runnable, MouseListener, MouseMotionListener
   private String m_strText;
   private Component m_Component;
   private Thread m_Thread;
   private int m_iX;
   private int m_iY;
   public ToolTip(Component comp, String strText);
      m_strText = strText;
      m_Component = comp;
      comp.addMouseMotionListener(this);
      comp.addMouseListener(this);
   public void run()
      try{
         Thread.sleep(500);
         // Here its time to display the tooltip:
         // We need to add it.
         Component comp = this;
         while((!comp instanceof Applet) &&
                 (!comp instanceof Frame))
            comp = comp.getParent();
         ((Container)comp).add(this);
         int x,y,w,h;
         x = m_iX+m_Component.getLocationOnScreen().x-comp.getLocationOnScreen.x;
         y = m_iY+m_Component.getLocationOnScreen().y - comp.getLocationOnScreen.y;
         h=30;
         w=getFontMetrics().stringWidth(m_strText);
         setBounds(x,y,w,h);
      cathc(InterruptedException e)
   public void mouseEntered(MouseEvent e)
      start(e.getX(), e.getY());
   private void start(int iX, int iY);
      m_iX = iX;
      m_iY = iY;
      m_Thread = new Thread(this);
      m_Thread.start();
   public void mouseExited(MouseEvent e)
      stop();
   public void mouseMoved(MouseEvent e)
      stop();
      start(e.getX(), e.getY());
   private void stop()
      if(m_Thread != null)
         m_Thread.interrupt();
      Container parent = getParent();
      if(parent != null)
         parent.remove(this);
   public void paint(Graphics g)
      g.drawString(m_strText, 0, 20);
      g.drawRect(0,0,getSize().width, getSize().height);
}The baseclass could be changed to java.awt.Window.
using Window gives the ToolTip the posibillity to extend beyond the borders of the Applet (or the Frame), but in IE it gives you the "warning applet window" displayed on the botton of every ToolTip.
Ragnvald Barth
Software engineer