Regex to find a float

Question

I've never used regex before, but this java function requires it (shown here: How to set Edittext view allow only two numeric values and two decimal values like ##.##)

I basically just need to get a float from it the text box, should be simple. I used a tool and it said this should work:

String re1="([+-]?\\d*\\.\\d+)(?![-+0-9\\.])";

But it doesn't seem to be working, it doesn't let me put anything in the text box.

What's the right way to do this? Thanks

Answer 1

Try this:

String re1="^([+-]?\\d*\\.?\\d*)$";

Answer 2

The right way for this problem isn't to use a regex, but just to use:

try {
     Float.parseFloat(string)
     return true;
}
catch (NumberFormatException ex) {
     return false;
}

Works perfectly fine, is the same code that is later used to parse the float and therefore bug free (or if it isn't we have a much bigger problem at hand).