Appending two arrays gives [__NSCFArray insertObject:atIndex:]: mutating method sent to immutable object'

Question

Hi I am using below line of code,where both of my responseJson and indexpathArray are NSmutableArrays

[responseJson addObject:indexpathArray];

but I m getting

Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '-[__NSCFArray insertObject:atIndex:]: mutating method sent to immutable object'

I have referred related topics Getting "mutating method sent to immutable object" error but still the same

Actually here I am trying to append records from new array to old array where I am Getting 10 records every time from server.

Any help is appreciated!

update

    NSMutableArray *arrayResult = [NSMutableArray arrayWithArray:responseJson];
    // Now add objects top arrayResult
    [arrayResult addObject:finalarray];

    NSLog(@" arrayResult before :::  %@",arrayResult);

    responseJson = [[NSMutableArray alloc]initWithArray:arrayResult];//carshing here now

update:

 - (void)saveNearMeData:(id)response
 {
   NSArray *finalarray1 = [[NSMutableArray alloc]init];
   NSMutableArray = [response valueForKey:@"Deals"];
  indexpathArray = [[NSMutableArray alloc]initWithArray:finalarray1];
   NSLog(@" finalarray before :::  %@",finalarray1);

    if(responseJson.count>0){

     NSMutableArray *arrayResult = [[NSMutableArray alloc]initWithArray:responseJson];;

    // Now add objects top arrayResult
    [arrayResult addObject:finalarray];

    NSLog(@" arrayResult before :::  %@",arrayResult);
    responseJson = arrayResult;

  }else{
        responseJson = [response valueForKey:@"Deals"];
    }
  }

please provide your json data and array detail for getting some idea.... — Ashish Ramani, Nov 23 '15 at 12:12
@Sujania Try like this [responseJson addObject:[indexpathArray mutableCopy]]; — Darshan Kunjadiya, Nov 23 '15 at 12:13
@DarshanKunjadiya that's the wrong way round, `responseJson` is immutable and needs to be mutable — Wain, Nov 23 '15 at 12:14
@Darshan Kunjadiya still the same crash..responseJson Array in mutable array — soumya, Nov 23 '15 at 12:16

Maulik Rajani · Accepted Answer · 2017-07-19T12:58:57.227

Please alloc your array at the time of assigning data while parsing. Hope that will resolve your crashing issue.

Objective-C

if ([arrayList count] == 0) {
                arrayList = [[NSMutableArray alloc] initWithArray:[response valueForKey:@"Deals"]];
} else {
        [arrayList addObjectsFromArray:[response valueForKey:@"Deals"]];
}

In Swift 3.0

if arrayList.count == 0 {
     arrayList = response.value(forKey: "Deals") as! Array
} else {
     arrayList += response.value(forKey: "Deals") as! Array
}

Saheb Roy · Answer 2 · 2015-11-23T12:44:22.730

2

From the log it seems that responseJson is an NSArray and addObject is an NSMutableArray method.

You can do the following

NSMutableArray *arrayResult = [NSMutableArray arrayWithArray:responseJson];
// Now add objects top arrayResult
[arrayResult addObject:indexpathArray];

You are again trying to init the responseJson with the Given array. I think the responseJson is an id, so casting it might solve the problem. Please post the declaration of the responseJson or the method where it is obtained. A safe bet would be to work with the arrayResult rather than the responseJson wherever you need it, and if you need it in any other method then please make arrayResult as an instance variable to obtain it globally.

edited Nov 23 '15 at 12:44

answered Nov 23 '15 at 12:15

Saheb Roy

5,899
3
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@Sujania : that means `responseJson` was `NSArray` and not `NSMutableArray` – Fahim Parkar Nov 23 '15 at 12:26
@Saheb Roy can you plz check my update once .. it is crashing. No it is an NSMutableArray – soumya Nov 23 '15 at 12:31
You still need to show what type of object is responseJson.. is it an `id`? – Saheb Roy Nov 23 '15 at 12:58

score 0 · Answer 3 · edited Nov 23 '15 at 12:34

0

You should use addObjectsFromArray method for example :

 NSArray *myArray = ...;
 NSMutableArray *bufferArray = [NSMutableArray new];
 [bufferArray addObjectsFromArray:myArray];

edited Nov 23 '15 at 12:34

Aviram Netanel

12,633
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answered Nov 23 '15 at 12:23

Marat Ibragimov

1,076
7
7

@RamaniAshish Sorry, had a typo it should be : [bufferArray addObjectsFromArray:myArray]; – Marat Ibragimov Nov 23 '15 at 12:30

score 0 · Answer 4 · answered Nov 23 '15 at 13:05

Apply deep copy every time you get the response from the server because when you get the response from the server end, generally it is immutable.

Below line do the mutability on each level of responseJson.

NSMutableArray *responseJson = (NSMutableArray
*)CFBridgingRelease(CFPropertyListCreateDeepCopy(kCFAllocatorDefault, (CFArrayRef)responseJson, kCFPropertyListMutableContainers));

You can also use the same line for NSMutableDictionary when you get the response in terms of the dictionary.

score 0 · Answer 5 · answered Nov 23 '15 at 13:10

0

Try this Solution:

I already have one array newsFeedListArry with objects & I am appending second array.

NSArray *arry = [NSArray arrayWithObject:@"TEstig"];
[newsFeedListArry addObjectsFromArray:arry];

answered Nov 23 '15 at 13:10

Hemali Luhar

349
1
11

score -1 · Answer 6 · answered Nov 23 '15 at 12:17

-1

What you can do is

NSMutableArray *test = [NSMutableArray arrayWithArray : responseJson];
[test addObjectsFromArray : indexpathArray];

answered Nov 23 '15 at 12:17

Avinash Sharma

111
1
11

And for your kind attention I have used addObjectsFromArray instead so please comment after reading properly – Avinash Sharma Nov 23 '15 at 12:53

Appending two arrays gives [__NSCFArray insertObject:atIndex:]: mutating method sent to immutable object'

6 Answers6