back space is not removing - symbol in text field - iphone

Question

I need to display mobile number in 123-456-7890 in text field. To do that, I am using this code:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSCharacterSet *numSet = [NSCharacterSet characterSetWithCharactersInString:#"0123456789-"];
NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
int charCount = [newString length];
if ([newString rangeOfCharacterFromSet:[numSet invertedSet]].location != NSNotFound
|| [string rangeOfString:#"-"].location != NSNotFound
|| charCount > 12) {
return NO;
}
if (charCount == 3 || charCount == 7) {
newString = [newString stringByAppendingString:#"-"];
}
textField.text = newString;
return NO;
}
it works fine,but I have a problem,
for example I need to display mobile number 1234567890 like this 123-456-7890.
I entered 123-456, by mistake I enter wrong value then to modify it backspace remove 456 but it is not removed - symbol.
How can I remove it also?

Answer 1

May be not a full solution, but a quick hack that should work - you can always let user delete any character (or substring), so try just put the following condition in the beginning of your method:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if ([string length] == 0)
return YES; // deleting is always OK - returning YES
...

Answer 2

I hope we can do it in this way:
NSMutableString *phoneNumber = [NSMutableString stringWithFormat:#"%#", textField.text];
[phoneNumber replaceOccurrencesOfString:#"-" withString:#"" options:NSBackwardsSearch range:NSMakeRange(0,[phoneNumber length])];
if([phoneNumber length] >=7) {
[phoneNumber insertString:#"-" atIndex:7];
}
if([phoneNumber length] >=3) {
[phoneNumber insertString:#"-" atIndex:3];
}
textField.text = phoneNumber;

Answer 3

You always return NO from the method, this means that in all cases you are not allowing textField to update the text through its internal logic, but you force it with the final statement
textField.text=newString;
This approach is correct, but your code contains a bug.
Infact suppose your current textfield string is "123-", as soon as you type backspace, the delegate is asked to replace "123-" with "123".
But in your code, you check that if the newString has length 3, then you append an extra "-".
So as soon as you type backspace to remove "-", then your code replace it with an extra "-".
In my opinion to fix it you should check if the textField.text length is > than newString. If so, then you are "deleting" and then you don't do the charCount==3 check, while if the textField.text length < newString length, then you are entering characters and you can do the check.

Answer 4

-(NSString*)formatNumber:(NSString*)mobileNumber
{
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"(" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#")" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#" " withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"-" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"+" withString:#""];
NSLog(#"%#", mobileNumber);
int length = [mobileNumber length];
if(length > 10)
{
mobileNumber = [mobileNumber substringFromIndex: length-10];
NSLog(#"%#", mobileNumber);
}
return mobileNumber;
}
-(int)getLength:(NSString*)mobileNumber
{
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"(" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#")" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#" " withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"-" withString:#""];
mobileNumber = [mobileNumber stringByReplacingOccurrencesOfString:#"+" withString:#""];
int length = [mobileNumber length];
return length;
}