iPhone keyboard layout for negative numbers?
问题 My users need to enter latitude and longitude, and of course I need to verify that the values entered are legitimate lat/long value. I'd like to have a keyboard layout that does some of this for me (eliminating alphabetic characters, punctuation, etc, and leaving only the numbers and +/-). The number pad keyboard doesn't seem to do it (missing +/-) and neither do any other keyboard layouts that come with the SDK. Does anyone know if there is a way to provide that capability without doing my