Question

Here is the code, I am hoping that this will add the constraint that only integer input is valid for the text field:

JFormattedTextField ftf =  new JFormattedTextField ();

NumberFormat format = NumberFormat.getNumberInstance();
format.setParseIntegerOnly(true);
ftf.setFormatterFactory(new DefaultFormatterFactory(new NumberFormatter(format), new NumberFormatter(format), new NumberFormatter(format)));

But what suprised me is that when I input 100aaa, it is valid, 100.111, it is valid too.
how can I make it to restrict that only integer is valid input?

Answer 1

You need to setAllowsInvalid(false) on the NumberFormatter objects.