jTextField validation for numbers and one decimal point?

Question

I need to set a jTextField to accept only numbers and one decimal point.Nothing else. Decimal point can\'t be typed more than once and no other characters are allowed. How c

Answer 1

You appear to be using a KeyListener to manage KeyEvents in theJTextField. This is not a suitable for filtering the document of this JTextComponent. Here you could use a JFormattedTextField combined with a MaskFormatter to accept a maximum 8 digits separated by a decimal point.

JFormattedTextField textField = new JFormattedTextField();
MaskFormatter dateMask = new MaskFormatter("####.####");
dateMask.install(textField);

For a more free-format input (e.g. more digits) you could use a DocumentFilter with a JTextField. Here is an integer filter example