i want to let the user type in the name of a new file, so there are certain characters i want to prevent entry on. is there a special keyboard i can use or can i disable certain keys on the iphones keyboard.
is the answer to just run a regular expression on the input text and tell the user the filename is invalid (if so what would that regular expression be?)
ANSWER: (or what i ended up doing)
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
BOOL valid;
//if the user has put in a space at the beginning
if ([string isEqualToString:@" "]){
if (range.location == 0){
valid = NO;
}
else{
valid = YES;
}
}
//otherwise test for alpha numeric
else{
NSCharacterSet *alphaSet = [NSCharacterSet alphanumericCharacterSet];
valid = [[string stringByTrimmingCharactersInSet:alphaSet] isEqualToString:@""];
}
//print the warning label
if (valid == NO){
[errorLabel setText:@"Invalid input"];
}
else{
[errorLabel setText:nil];
}
return valid;
}