Reg focus events

[Kajol Shroff]

Hi everybody,
I am in after almost a year.
I have a problem..
I create multiple textfields using a for loop and in that texfield I give some default value.
I want to keep a check that the value set in the textfield shouldnt exceed say 20 it can be anything above default which is say 0.5 and below 20.
How do I do that?
As its an array of textfields... I am getting confused ..
Please help
I hope I will get the same prompt replies as I use to get previously..
Kajol Shroff

[Manfred Leonhardt]

Hi Kajol,
I would take the approach to use Document override JTextField and use that to limit the user input. Look at the class below.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class FloatField extends JTextField 
{
  private double lowerLimit;
  private double upperLimit;
  public FloatField( int cols, double lowerLimit, double upperLimit ) 
  {
    super( cols );
    this.lowerLimit = lowerLimit;
    this.upperLimit = upperLimit;
  }
  public FloatField( int cols ) 
  {
    this( cols, Double.MIN_VALUE, Double.MAX_VALUE );
  }
  public void setLimits( double lowerLimit, double upperLimit )
  {
    this.lowerLimit = lowerLimit;
    this.upperLimit = upperLimit;
  }
  protected Document createDefaultModel() 
  {
    return new LimitDocument();
  }
  class LimitDocument extends PlainDocument 
  {
    public void insertString( int offs, String str, AttributeSet a ) 
                throws BadLocationException 
    {
      if( str != null ) 
      {
        //
        // Make sure value is a legitimate double value.
        //
        try
        {
          String newStr = getText( 0, getLength() ) + str;
          double f = Double.parseDouble( newStr );
          //
          // Make sure we are within our limits.
          //
          if( f >= lowerLimit && f <= upperLimit )
          {
            super.insertString( offs, str, a );
          }
        }
        catch( NumberFormatException nfe )
        {}
      }
    }
  }
  
  public static void main( String[] args )
  {
    Frame f = new Frame();
    f.setLayout( new FlowLayout() );
    f.setSize( 500, 200 );
    f.addWindowListener(
      new WindowAdapter()
      {
        public void windowClosing( WindowEvent we )
        {
          System.exit( 0 );
        }
      });
    FloatField lf = new FloatField( 6, .5, 20 );
    f.add( lf );
    f.setVisible( true );
  }
}

Regards,
Manfred.

[Kajol Shroff]

Hi Manfred,
Thanks for the help.. I could solve the probelm which I was facing about the arrays ..no I have so other problem here....in my program I am not using Swings ... they are just simple applets which have panels in the cardlayout ..
In the panels the first panel is the Personal details ...and in that I have a TextArea where in I need focus because when I give tab to the TextArea it dosent set focus to the next textfield which is below the TextArea
Please get back to me ...on this
[ March 27, 2002: Message edited by: Kajol Shroff ]