How to insert a string automatically while user editing UITEXTFIELD - ios

Question

I want to my uitextfield be like XXX.XXX.XXX/XX at the end of typing.
To limit the lenght I use this:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField == _cpfField) {
NSUInteger newLength = [textField.text length] + [string length] - range.length;
NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:NUMBERS_ONLY] invertedSet];
NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:#""];
return (([string isEqualToString:filtered])&&(newLength <= CHARACTER_LIMIT));
} else{
return YES;
}
}
The problem is how to insert the "." and "/" while user still editing it.

Answer 1

The following code should do the following:
Limit the number of characters that can be typed/pasted into the text field
Automatically add periods and slashes at the appropriate locations
Prevent issues from the user copy/pasting a string that already has the necessary periods/slashes
That said, there is almost certainly more efficient ways to do this; but if you're not concerned about code length it'll do the trick just fine.
- (BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *text = textField.text;
// If we're trying to add more than the max amount of characters, don't allow it
if ([text length] == 14 && range.location > 13) {
return NO;
}
// First lets add the whole string we're going for
text = [text stringByReplacingCharactersInRange:range withString:string];
// Now remove spaces, periods, and slashes (since we'll add these automatically in a minute)
text = [text stringByReplacingOccurrencesOfString:#" " withString:#""];
text = [text stringByReplacingOccurrencesOfString:#"." withString:#""];
text = [text stringByReplacingOccurrencesOfString:#"/" withString:#""];
// We need to use an NSMutableString to do insertString calls in a moment
NSMutableString *mutableText = [text mutableCopy];
// Every 4th char will be a '.', but we don't want to check more than the first 8 characters
for (NSUInteger i = 3; i < mutableText.length && i < 8; i += 4) {
[mutableText insertString:#"." atIndex:i];
}
// If the text is more than 11 characters, we also want to insert a '/' at the 11th character index
if (mutableText.length > 11) {
[mutableText insertString:#"/" atIndex:11];
}
// lets set text to our new string
text = mutableText;
// Now, lets check if we need to cut off extra characters (like if the person pasted a too-long string)
if (text.length > 14) {
text = [text stringByReplacingCharactersInRange:NSMakeRange(14, mutableText.length-14) withString:#""];
}
// Finally, set the textfield to our newly modified string!
textField.text = text;
return NO;
}

Answer 2

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
NSString *text = textField.text;
text = [text stringByReplacingCharactersInRange:range withString:string];
text = [text stringByReplacingOccurrencesOfString:#"." withString:#""];
// Do your length checking here
NSMutableString *mutableText = [text mutableCopy];
// Every 4th char will be a .
for (NSUInteger i = 3; i < mutableText.length; i += 4) {
[mutableText insertString:#"." atIndex:i];
}
textField.text = mutableText;
return NO;
}

Answer 3

UK National Insurance Number Text Field
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (textField == _txtNationalInsuranceNumber) {
NSString *text = textField.text;
// If we're trying to add more than the max amount of characters, don't allow it
if ([text length] == 13 && range.location > 12) {
return NO;
}
// First lets add the whole string we're going for
text = [text stringByReplacingCharactersInRange:range withString:string];
// Now remove spaces, periods, and slashes (since we'll add these automatically in a minute)
text = [text stringByReplacingOccurrencesOfString:#" " withString:#""];
// We need to use an NSMutableString to do insertString calls in a moment
NSMutableString *mutableText = [text mutableCopy];
// Every 4th char will be a '.', but we don't want to check more than the first 8 characters
for (NSUInteger i = 2; i < mutableText.length && i < 10; i += 3) {
[mutableText insertString:#" " atIndex:i];
}
// If the text is more than 11 characters, we also want to insert a '/' at the 11th character index
if (mutableText.length > 11) {
[mutableText insertString:#" " atIndex:11];
}
// lets set text to our new string
text = mutableText;
// Now, lets check if we need to cut off extra characters (like if the person pasted a too-long string)
if (text.length > 14) {
text = [text stringByReplacingCharactersInRange:NSMakeRange(14, mutableText.length-14) withString:#""];
}
// Finally, set the textfield to our newly modified string!
textField.text = text;
return NO;
}
else
{
return YES;
}
}