TextEvent
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Event Handling for TextField
TextEvent class and TextListener interface are associated with both textfield and textarea. If we want to performed any operation, if the value of textfield and textarea are changed than the logic should be written in the textValueChanged().
| GUI Component | Event class | Listener Interface | Method (abstract method) |
|---|---|---|---|
| TextField | TextEvent | TextListener | public void textValueChanged(TextEvent e) |
Example of TextEvent
import java.awt.*;
import java.awt.event.*;
class TextEventEx extends Frame implements TextListener
{
TextField tf1,tf2,tf3;
Label l1,l2,l3;
String nm="",xc="",yc="";
int x,y;
Panel p1;
TextEventEx()
{
setBackground(Color.cyan);
p1=new Panel();
p1.setBackground(Color.yellow);
l1=new Label("Name");
l2=new Label("X-axies");
l3=new Label("y-aixes");
tf1=new TextField(15);
tf2=new TextField(5);
tf3=new TextField(5);
p1.add(l1);
p1.add(tf1);
p1.add(l2);
p1.add(tf2);
p1.add(l3);
p1.add(tf3);
add("North",p1);
tf1.addTextListener(this);
tf2.addTextListener(this);
tf3.addTextListener(this);
}
public void textValueChanged(TextEvent e)
{
nm=tf1.getText();
xc=tf2.getText();
x=Integer.parseInt(xc);
yc=tf3.getText();
y=Integer.parseInt(yc);
repaint();
}
public void paint(Graphics g)
{
setFont(new Font("TimesRoman",Font.BOLD,30));
g.setColor(Color.red);
g.drawString("Name"+nm,x,y);
}
public static void main(String args[])
{
TextEventEx t=new TextEventEx();
Toolkit tx=Toolkit .getDefaultToolkit();
t.setSize(tx.getScreenSize());
t.setVisible(true);
}
}
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