objective-c - uncaught - unrecognized selector sent to instance swift 3

[__NSCFDictionary objectAtIndex:]: selector no reconocido enviado a la instancia

Question

Estoy tratando de analizar un archivo Json en la vista Tabla y estoy obteniendo este error

[__NSCFDictionary objectAtIndex:]: selector no reconocido enviado a la instancia y la aplicación se bloquea. Por favor, ayúdenme, soy nuevo en el desarrollo de iOS.

Mi código

@implementation ViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
self.title = @"Feeds";
[super viewDidLoad];
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSURL *url = [NSURL URLWithString:@"http://little-people.blogspot.com/feeds/posts /default?alt=json"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
data = [[NSMutableData alloc] init];
NSLog(@"Data Data , %@", data);
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)theData
{
[data appendData:theData];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
feed = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSLog(@"Data , %@", feed);
[mainTableView reloadData];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
UIAlertView *errorView = [[UIAlertView alloc] initWithTitle:@"Error" message:@"The download could not complete - please make sure you''re connected to either 3G or Wi-Fi." delegate:nil cancelButtonTitle:@"Dismiss" otherButtonTitles:nil];
[errorView show];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (int)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (int)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [feed count];
NSLog(@"Data Data , %@", feed);
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"MainCell"];
if(cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"MainCell"];
}
if (([feed count] - 1) >=indexPath.row) {
cell.textLabel.text = [[feed objectAtIndex:indexPath.row] objectForKey:@"feed"];
cell.detailTextLabel.text = [[feed objectAtIndex:indexPath.row] objectForKey:@"title"];
}
return cell;
}

Answer 1

El objeto de nivel superior en su feed es un objeto JSON, no una matriz JSON. Entonces la deserialización te da un NSDictionary, no un NSArray.

Answer 2

El problema es que el feed no es un NSArray , sino un NSDictionary .

Al mirar el JSON, es probable que desee acceder a este conjunto: [feed objectForKey:@"entry"]