Validation

hitesh kalra

I want that in textbox if 0 is insert than it shows an alert message. The textbox insert numbers only. How will I validate it? please help thanx in advance.

4277480

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

public class Validate extends JFrame
{
TextField t;
public Validate()
{
t= new TextField(10);
add(t);
t.addKeyListener(new KeyAdapter()
{
public void keyPressed(KeyEvent e)
{
int key = e.getKeyCode();
if ((key == KeyEvent.VK_0))
{
JOptionPane.showMessageDialog(null,"0 Was Clicked", "Note",JOptionPane.INFORMATION_MESSAGE);
}
else
if((key == KeyEvent.VK_1)||(key == KeyEvent.VK_2)||(key == KeyEvent.VK_3)||(key == KeyEvent.VK_4)||(key == KeyEvent.VK_5)||(key == KeyEvent.VK_6||(key == KeyEvent.VK_7)||(key == KeyEvent.VK_8)||(key == KeyEvent.VK_9)))
{
return;
}
else
{
JOptionPane.showMessageDialog(null,"Invalid Input", "Note",JOptionPane.WARNING_MESSAGE);
String s = t.getText();
t.setText(s.replaceAll(e.getKeyChar()+"",""));

				}
		}
	}
	);
	setTitle("Validate");
	setLocationRelativeTo(null);
	pack();
	setDefaultCloseOperation(JFrame.EXIT\_ON\_CLOSE);
	setVisible(true);
}
public static void main(String\[\] args) 
{
	new Validate();
}

}

David Skelly

Would it not be simpler to use a JFormattedTextField to ensure numeric input and an InputVerifier to check the value is not 0?

4277480

True there are many ways to do it. Snippet 1: Integers

public Validate()
{
Text.addKeyListener(new KeyAdapter()
{
public void keyTyped(KeyEvent e)
{
char c = e.getKeyChar();
if (!(Character.isDigit(c) ||(c == KeyEvent.VK_BACK_SPACE) ||(c == KeyEvent.VK_DELETE)))
{
getToolkit().beep();
e.consume();
}
if( c == KeyEvent.VK_0)
{
Label.setText("0 entered");
Label.setForeground(Color.red);
}
else
{
Label.setText("ok");
Label.setForeground(Color.black);
}
}
});

Snippet 2: Double

public class Validate()
{
DoubleValidate dv = new DoubleValidate();
public Validate()
{
Text.setDocument(dv);
add(Text);
}

static class DoubleValidate extends PlainDocument 
{
	public void insertString(int offset,String string, AttributeSet attributes)throws BadLocationException 
	{
		if (string == null) 
		{
			return;
		} 
		else 
		{
			String newValue;
			int length = getLength();
			
			if (length == 0) 
			{
				newValue = string;
			} 
			else 
			{
				String currentContent = getText(0, length);
				StringBuffer currentBuffer = new StringBuffer(currentContent);
				currentBuffer.insert(offset, string);
				newValue = currentBuffer.toString();
			}
			try 
			{
				Double.parseDouble(newValue);
				super.insertString(offset, string,attributes);
			} 
			catch (NumberFormatException exception) 
			{
				Toolkit.getDefaultToolkit().beep();
			}
		}
	}
}

}

David Skelly

Yes, there are many ways to make something more complicated than it needs to be.