[963] in java-interest
Re: Scrolling & Stuff
daemon@ATHENA.MIT.EDU (Lein Ton)
Tue Aug 15 22:51:36 1995
Date: Tue, 15 Aug 1995 11:26:34 -0400
From: ton@cc.gatech.edu (Lein Ton)
To: rharriso@elmer.tcinc.com, java-interest@java.sun.com
Hi Ray,
I think by now you figured out how the scrolling works, but in case
you didn't, you might wanna look at the program beneath. It's
not a very nice way of scrolling, but it works. If you plan on
scrolling a lot of objects this way you might consider putting
everything in a window and move the window instead of the
individual things.
You also might wanna look at
http://java.sun.com/archives/java-interest/0761.html
in case you want to delete things from a window, I figured that the
easiest way of clearing the childList is to create a new one and
copy the items that are not deleted to the new one, and assign it
to ScrollWindow.childList.
If you found an easier way of scrolling, please let me know!
Lein
------------little program that demonstrates "scrolling"-------
import awt.*;
import java.util.*;
class ScrollWindow extends Window {
//variables; static because they're defined in the object that contains "main"
public static Label l;
public static Button b;
public static Scrollbar sb;
//oldY contains the previous value of the scrollbar
public static int oldY=0;
//constructor
public ScrollWindow(Frame f, String name) {
super (f,name,Color.green,200,200);
}
//implementation of dragAbsolute; called by the scrollbar when it is dragged
public void dragAbsolute(int value) {
for (Enumeration e = children.elements(); e.hasMoreElements();)
{
int dy = oldY-sb.value();
Component c = ((Component)(e.nextElement()));
c.move(0,c.y-dy);
}
oldY=sb.value();
}
public static void main (String args[]) {
// create a ScrollWindow
WServer ws = new WServer();
ws.start();
Frame fr = new Frame(ws,false,null,200,200,Color.lightGray);
fr.name = "myframe";
ScrollWindow sw = new ScrollWindow(fr,"swname");
// attach a ScrollBar
sb = new Scrollbar(sw,"sbName",Scrollbar.VERTICAL,true);
sb.setScrollTarget(sw);
// put something in the window to demonstrate scrolling
l = new Label("I can move","icml", sw);
b = new Button("I can move 2","icmb",sw);
b.move(50,50);
fr.map();
}
}
-
Note to Sun employees: this is an EXTERNAL mailing list!
Info: send 'help' to java-interest-request@java.sun.com
