Error when swipe to delete a table cell - objective-c

Question

I'm trying to delete a row when user swipes. I got this error driving me crazy. I've spent last three hours trying to figure out why. But, I have got no clue so far.
Here is my code to accomplish that.
in .h
#import <UIKit/UIKit.h>
#import "CustomCell.h"
#interface FollowersTableViewController : UITableViewController
#property (nonatomic,strong)NSMutableArray *arrayWithUser ;
#end
and in .m i have this code .
#import "FollowersTableViewController.h"
#implementation FollowersTableViewController
#synthesize arrayWithUser ;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
-(void)viewDidLoad
{
[super viewDidLoad];
NSDictionary *dicUrlList= [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"Urls" ofType:#"plist"]];
NSString *baseURl = [dicUrlList objectForKey:#"urlWithUser"];
baseURl = [baseURl stringByAppendingFormat:#"getfollowers"];
NSURL *urlToGetFollowers = [NSURL URLWithString:baseURl];
NSURLRequest *request = [NSURLRequest requestWithURL:urlToGetFollowers];
NSError *error = nil ;
NSURLResponse *response = nil ;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
arrayWithUser = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
}
- (void)viewDidUnload
{
[super viewDidUnload];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [arrayWithUser count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *MyIdentifier = #"Cell";
CustomCell *customCell = (CustomCell *)[tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (customCell == nil)
{
customCell = [[CustomCell alloc] initWithFrame:CGRectMake(0, 0, 320, 50)] ;
}
NSDictionary *dicWithUser = [arrayWithUser objectAtIndex:indexPath.row];
NSString *photoUrl = [dicWithUser objectForKey:#"profilePhotoUrl"];
if(![photoUrl isEqualToString:#""])
[customCell.thumbnail setImageWithURL:[dicWithUser objectForKey:#"profilePhotoUrl"] placeholderImage:[UIImage imageNamed:#"placeholder.png"] ];
else
{
[customCell.thumbnail setImage:[UIImage imageNamed:#"placeholder.png"]];
}
customCell.titleLabel.text = [dicWithUser objectForKey:#"username"];
UIButton *buttonFollow = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[buttonFollow setTitle:#"Follow" forState:UIControlStateNormal];
CGRect frame = buttonFollow.frame ;
frame = CGRectMake(200, 10, 60, 30);
buttonFollow.frame = frame ;
buttonFollow.tag = indexPath.row ;
[buttonFollow addTarget:self action:#selector(followButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
customCell.accessoryView = buttonFollow ;
return customCell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 60 ;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[arrayWithUser removeObjectAtIndex:indexPath.row];
}
}
So far,I'm able to see delete button, but when i pressed it gives me this error
[__NSCFArray removeObjectAtIndex:]: mutating method sent to immutable object.
Since I've already used NSMutableArray, I've no idea, why I'm getting this error?
I've already try to clean project. It didn't make any difference.

Answer 1

Your Json call returning an NSArray. You can go to create a mutableCopy - so you're will be able to use the "removeAtIndex.." method.
NSArray *rData = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
arrayWithUser = [rData mutableCopy];

Answer 2

The assignment to arrayWithUser from the JSON call is returning an NSArray not an NSMutableArray in viewDidLoad. Fix that.

Answer 3

Actually, your array(arrayWithUser) is strongly pointing to the array return by the JSONObjectWithData, as you don't have the ownership of the returned array, you can't remove its object.
You better do one thing ,take ownership of that array.
arrayWithUser = [[NSMutableArray alloc]arrayByAddingObjectsFromArray:[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil]];

Answer 4

Just replace below line
arrayWithUser = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
with
arrayWithUser = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
From Apple's documentation:
NSJSONReadingMutableContainers: Specifies that arrays and dictionaries are created as mutable objects.
NSJSONReadingMutableLeaves: Specifies that leaf strings in the JSON object graph are created as instances of NSMutableString.

Answer 5

You used in viwDidLoad
arrayWithUser = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];
Lets try like this
NSMutableArray *userMutarr = [NSMutableArray alloc]initWithCapacity:3];
self.arrayWithUser = userMutarr;
[userMutarr release];
Then
self.arrayWithUser = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:nil];