How to add an object to a NSMutable array that is in a class?

Question

I am trying to add an object of the same class to a NSMutable array that is defined in the same class. My approach would look like this, but when I tested the array, it was always empty. I also tried adding random Strings or integers.

The .h file:

@property NSMutableArray *anArray;
- (void)addObject: (TheClass*)nameOfObjectToBeAdded;

The .m file:

@synthesize anArray;

- (void)addObject: (TheClass*)nameOfObjectToBeAdded {
    [anArray addObject:nameOfObjectToBeAdded];
}

The main.m:

#import "TheClass.h"

int main(int argc, char *argv[])
{
    @autoreleasepool {

        TheClass *object1 = [[TheClass alloc] init];
        TheClass *object2 = [[TheClass alloc] init];
        [object1 addObject:object2];

    }
    return 0;
}

I am trying to add object2 to the NSMutableArray of object1.

Thanks in advance!

score 3 · Accepted Answer · answered May 08 '12 at 14:57

3

You need to allocate and initialize the array before using it:

In Class.m, probably in init:

self.anArray = [[NSMutableArray alloc] init];

answered May 08 '12 at 14:57

kevboh

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Great, if it worked for you feel free to mark the answer as correct. – kevboh May 08 '12 at 15:35

score 1 · Answer 2 · answered May 08 '12 at 14:58

1

You need to create NSMutableArray at first..

NSMutableArray *anArray = [NSMutableArray array];
[anArray addObject:object];

answered May 08 '12 at 14:58

beryllium

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score 0 · Answer 3 · answered May 08 '12 at 15:00

0

Add the allocation in your classes initializer as such:

In ThisClass

-(id) init: {
  self = [super init];
  if(self) {
    self.anArray = [[NSMutableArray alloc] init];
    /* ... other initializer stuff ... */
  }
  return self;
}

answered May 08 '12 at 15:00

lukecampbell

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How to add an object to a NSMutable array that is in a class?

3 Answers3