CODEWITHSUNDEEP
iphoneobjective-ciosarraysipad
Imme22009
Imme22009

Reputation: 4129

Objective c add string object to an array

I've looked everywhere for this, online, on stack overflow and cannot still work out what I'm doing wrong.

I'm trying to add an element to an existing NSMutableArray. But it crashes on line 4:

-[__NSArrayI addObject:]: unrecognized selector sent to instance 0x897b320

The code:

NSMutableArray *mystr = [[NSMutableArray alloc] init];

mystr = [NSArray arrayWithObjects:@"hello",@"world",@"etc",nil];

NSString *obj = @"hiagain";

[mystr addObject:obj];

What am I doing wrong? This is driving me crazy!!!

Upvotes: 8

Views: 43555

Answers (5)

Imme22009
Imme22009

Reputation: 4129

Ahhhhh spotted it already

Line 2 should be:

[NSMutableArray arrayWithObjects:@"hello",@"world",@"etc",nil];

Sorry to waste your time with that!

Upvotes: 0

Robert Zahm
Robert Zahm

Reputation: 1877

You originally create mystr as a mutable array, but then assign it to a standard NSArray in the next line. Instead of calling "arrayWithObjects," add each item using "addObjects" or some other function that doesn't create a new immutable array.

Upvotes: 0

Eimantas
Eimantas

Reputation: 49354

The second line you're reassigning an instance of NSArray rather of NSMutableArray to your mystr variable.

Try something like this:

NSMutableArray *mystr = [NSMutableArray  arrayWithObjects:@"hello",@"world",@"etc",nil];

[mystr addObject:@"hiagain"]

Upvotes: 0

rmaddy
rmaddy

Reputation: 318814

Your code should be:

NSMutableArray *mystr = [[NSMutableArray alloc] initWithObjects:@"hello",@"world",@"etc",nil];

NSString *obj = @"hiagain";

[mystr addObject:obj];

Upvotes: 3

giorashc
giorashc

Reputation: 13713

You array is not mutable!. Use NSMutableArray 

mystr = [NSMutableArray arrayWithObjects:@"hello",@"world",@"etc",nil];

You get unrecognized selector since NSArray does not contain the addObject method

Upvotes: 14

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