Function fltk::dialog::file_chooser

pub fn file_chooser(
    message: &str, 
    pattern: &str, 
    dir: &str, 
    relative: bool
) -> Option<String>

Shows a file chooser returning a String. Example:

use fltk::*;
let file = dialog::file_chooser("Choose File", "*.rs", ".", true).unwrap();
println!("{}", file);