Write only one number in text field [closed]

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How can i let user write only one number in text field? Other should be consume.

I have code for write number.

private boolean number(char zn){
    if(zn>='0' && zn<='9')
        return true;

    return false; 
    }

Answer 1

You state that this is a Swing question, and so I assume that you are using a JTextField. If so, you have one of two possible solutions here:

• Use a JFormattedTextField and use a MaskFormatter, something simple like "#" should probably work perfectly here.
• Or get the JTextField's Document and set its DocumentFilter with one that restricts input to as you deserve it. I think that this would be unnecessarily complex for you, and I recommend the first option.

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Check the tutorial on how to use JFormattedTextFields which you can find here: JFormattedTextField Tutorial. It will explain all of the above including how to use a mask formatter with JFormattedTextFields.

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