I don’t know how to collect the input from the user in eclipse with slick2D, and I want that the input of the user can only be a ‘int’ not a ‘string’ because I need to make some maths with it.

When I run my code I have a rectangle in which I can write anything I want but the thing is that I want that the user can only put numbers.
And, I just don’t know how I’m supposed to collect the input from the user to use it afterward.