does anyone knoe if the digitizer has to be replaced when replacing a cracked screen? the phone screen still displays images but the screen is cracked? ive had some tell me you have to replace the screen glass and digitizer together?

thanks

does anyone know if you can just replace the cracked glass on the galazy 4? everyone else is telling me I would have to replace digitizer as well... the images still show on the phone its just the screen has a crack? thanks