Scrollbar Example Java Applet
In this example we
will learn how we can create Scrollbar in java. In this example we are
creating three Scrollbar .These Scrollbars are used to set
background color. Here we are using
Scrollbar class to strong an object of scrollbar .We are using
Scrollbar(int x,int y, int x1,int y1,int m) constructor to create new object
of scrollbar. We are using Panel class to create a new panel. In this
panel we are adding these three scrollbars.To add the scrollbars at panel we are
using add() method. We are using GridLayout and BorderLayout
here to set layout .To set layout we are using setLayout()
method. As you can see here we are using two layout. The GridLayout is
used to set component into panel and BorderLayout is used to set
the panel at north
As we know , we can
apply AdjustmentListener on Scrollbar. To register on
scrollbar we are using addAdjustmentListener(). We are using
adjustmentValueChanged(AdjustmentEvent e) to handle the change on
scrollbar .The AdjustmentEvent class is used to store the actions
by scrollbars into an object. We are using getValue() method to
get the current position. We are taking position of three scrollbar into three
variable and finally we are passing these values into Color(int x,int y,int
z) Thus we are getting different values from three scrollbars which will
gives different color to set the background color .
To show three values on status bar we are using showStatus(String str)
method.
SOURCE CODE
//<applet code=ScrollbarExample height=300 width=400> </applet>
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class ScrollbarExample extends Applet implements AdjustmentListener
{
// style(0-H/1-V),initialvalue, thumbsize,min,max)
Scrollbar r = new Scrollbar(0,1,20,1,275);
Scrollbar g = new Scrollbar(0,1,20,1,275);
Scrollbar b = new Scrollbar(0,1,20,1,275);
Panel p = new Panel();
public void init()
{
p.setLayout(new GridLayout(3,1));
setLayout(new BorderLayout());
p.add(r);
p.add(g);
p.add(b);
add(p,"North");
r.addAdjustmentListener(this);
g.addAdjustmentListener(this);
b.addAdjustmentListener(this);
}
public void adjustmentValueChanged(AdjustmentEvent e)
{
int cr,cg,cb;
cr =r.getValue();
cg =g.getValue();
cb =b.getValue();
showStatus("Color is --> r = "+cr+" , g = "+cg+" , b = "+cb);
setBackground(new Color(cr,cg,cb));
}
}
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