Inserting text into the string in iOS

Question

I need my user to enter numbers to type his telephone number.The user can only enter 8 numbers(for eg. XXXXXXXX). I need to change the phone number to be in the format XX-XX-XXXX.

This is what I have tried:

[tfDID.text insertString:@"-" atIndex:2];
[tfDID.text insertString:@"-" atIndex:5];

But it is returning me an error saying:

No Visible @interface for 'NSString' declares the selector 'insertString:atIndex:'

Need some guidance on this. Sorry if this is a stupid question.

Can you add your declaration of tfDID in .h file here ? – Bhavin Jan 04 '13 at 10:20 — Bhavin, Jan 04 '13 at 10:20

Anoop Vaidya · Accepted Answer · 2013-01-04T10:26:28.707

No Visible @interface for 'NSString' declares the selector 'insertString:atIndex:'

As you are trying to mutate the textbox's value, which returns you NSString.

NSString object can not be mutated, so convert it into a mutable string then manupulate it.

Make your string NSMutableString.

As,

NSMutableString *tfDIDString=[NSMutableString stringWithString:tfDID.text];
[tfDIDString insertString:@"-" atIndex:2];
[tfDIDString insertString:@"-" atIndex:5];

score 4 · Answer 2 · answered Jan 04 '13 at 10:22

4

[UITextField text] is NSString, you need to declare local variable of NSMutableString and perform insertString operations on it

Hope it helps you

answered Jan 04 '13 at 10:22

P.J

6,547
9
44
74

score 1 · Answer 3 · answered Jan 04 '13 at 10:24

1

Implement <UITextFieldDelegate> and then do:

-(void)textFieldDidChange:(UITextField*)textField
{
    if( textField.text.length == 2 || textField.text.length == 5 ){
        textField.text = [textField.text stringByAppendingString:@"-"];
    }
}

answered Jan 04 '13 at 10:24

Roland Keesom

8,180
5
45
52

score 1 · Answer 4 · answered Jan 04 '13 at 10:25

Completely agree with the answer suggesting making it a mutable string. Just to play devils advocate you could do:

NSString *partOne = [NSString stringWithRange:NSMakeRange(0,2)];
NSString *partTwo = [NSString stringWithRange:NSMakeRange(2,2)];
NSString *partThree = [NSString stringWithRange:NSMakeRange(4,4)];

NSString *formattedNumber = [NSString stringWithFormat:@"%@-%@-%@",partOne,partTwo,partThree];

I've written it out longhand but you could compress the string declarations for the parts in to the stringWithFormat call if you don't mind nesting and sacrifcing a bit of readability.

Inserting text into the string in iOS

4 Answers4