Solved

Controlling text in a JTextField.

Posted on 2004-03-30
11
262 Views
Last Modified: 2010-03-31
I have 2 books on Java and wouldn't you knon it, neither one gives me the information I want!

How can I control what charactors that can be entered and the number of charactors that can be entered into a JTextField?

Thanks in advance.

David, a.k.a. TrainMan
0
Comment
Question by:TrainMan
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
  • 2
  • +1
11 Comments
 
LVL 92

Expert Comment

by:objects
ID: 10719792
use a custom Document.
0
 
LVL 92

Accepted Solution

by:
objects earned 60 total points
ID: 10719800
public class FieldDocument extends PlainDocument
{
     private int limit;

     public FieldDocument(int limit)
     {
          super();
          this.limit = limit;
     }

     public void insertString(int offset, String s, AttributeSet attributeSet)
          throws BadLocationException
     {
          if (limit==0 || getLength() + s.length() < limit)
          {
  // if we haven't reached the limit, insert the string
               super.insertString(offset, s, attributeSet);
          }
          else
          {
                        // otherwise, just lose the string

               Toolkit.getDefaultToolkit().beep();
          }
     
     }
}
0
 
LVL 92

Expert Comment

by:objects
ID: 10719809
You can use a similiar technique to limit what characters can be entered.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 

Author Comment

by:TrainMan
ID: 10720235
Thanks for the input.  But while this is an answer, it isn't what I'm looking for.  
So let me clearify my question.

How can I do this for each charactor as it is entered?
I do believe that that is posible using MFC C++ in Windows.

David
0
 
LVL 92

Expert Comment

by:objects
ID: 10720270
the above will handle that, insertString() is called whenever any character(s) are inserted into the text field.
0
 
LVL 9

Expert Comment

by:mmuruganandam
ID: 10720984
http://www.iam.ubc.ca/guides/javatut99/uiswing/components/textfield.html

This might help you in validating each and every character that you enter.


Otherwise, you can add the key listener to your text fields.  So that you will get the event firing for every key you press.
0
 
LVL 9

Expert Comment

by:mmuruganandam
ID: 10721029
http://java.sun.com/developer/JDCTechTips/2001/tt1120.html

This would also help you.  There are more than one way to control your text.
0
 
LVL 30

Expert Comment

by:Mayank S
ID: 10721158
objects' code should help. Have a look at this for more example:

http://www.experts-exchange.com/Programming/Programming_Languages/Java/Q_20910569.html
0
 

Author Comment

by:TrainMan
ID: 10725112
Boy, I asked for help and I sure got it.  Thanks to evaryone.

I'll need a couple of days though to sort through all of the suggestions.

Talk to you then.

TrainMan
0
 

Author Comment

by:TrainMan
ID: 10766569
Sorry everyone.  It  was my intent to split the point to the 3 of you.

TrainMan
0
 
LVL 30

Expert Comment

by:Mayank S
ID: 10767755
You can post a question in Community Support asking them to re-open this question so that you can split between the 3, or you can post points for mmuruganandam and mayankeagle in separate questions, giving links to this one and ask them to post comments on those, so that you can accept them and give the points.
0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction Java can be integrated with native programs using an interface called JNI(Java Native Interface). Native programs are programs which can directly run on the processor. JNI is simply a naming and calling convention so that the JVM (Java…
Introduction This article is the first of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article explains our test automation goals. Then rationale is given for the tools we use to a…
Viewers learn about the scanner class in this video and are introduced to receiving user input for their programs. Additionally, objects, conditional statements, and loops are used to help reinforce the concepts. Introduce Scanner class: Importing…
This video teaches viewers about errors in exception handling.
Suggested Courses

622 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question