CODEWITHSUNDEEP
objective-cnsstring
Linuxmint
Linuxmint

Reputation: 4746

Concatenating string from UIAlertView text field

I've got a UIAlertView with a text field (alertView). Let's just say I type in "Asdf" in the UIAlertView text field.

In the first line, I grab the text from that field and create *myString from it.

NSString *myString = [alertView textFieldAtIndex:0].text;

On the 2nd line, I display this string in the NSLog with an addition. 

NSLog(@"My String is: %@", myString);

This displays properly in the NSLog:

My String is: Asdf

So then on the 3rd line I create an NSString with this addition + my original string (myString). Finally on the 4th line I display this second string in the NSLog.

NSString *mySecondString = (@"My String is: %@", myString);
NSLog(@"%@", mySecondString);

On the 3rd line (mySecondString = ...), I get a warning saying

Expression result unused

The NSLog for this displays improperly as such:

Asdf

I'm sure I'm missing something very simple so if you spot something it would be much appreciated.

Upvotes: 0

Views: 235

Answers (1)

Brian Tracy
Brian Tracy

Reputation: 6831

That's not how you concatenate strings in Objective-C
To properly concatenate two NSString instances, there are a few options.

Option #1. +stringWithFormat class method.

NSString *a = @"hello";
NSString *b = @"world";

NSString *c = [NSString stringWithFormat:@"%@%@", a, b];

Option #2, -stringByAppendingString instance method.

NSString *a = @"hello";
NSString *b = @"world";

NSString *c = [a stringByAppendingString:b];

In your case, you could use the following.

NSString *mySecondString = [NSString stringWithFormat:@"%@%@",@"My String is:", myString];

Upvotes: 2

Related Questions