Question

How to parse a a JSON string in iOS app? Using SBJSON. Running the code below. Getting data is successful but the count on the number of entries in the array is zero even tho the JSON string contains entries. My question is how query the JSON string in a loop?

Thanks!

// Create new SBJSON parser object
SBJsonParser *parser = [[SBJsonParser alloc] init];

// Prepare URL request to download statuses from Twitter
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://safe2pee.org/api/proxlist.php?location=37.7626214,-122.4351661&distance=1"]];

// Perform request and get JSON back as a NSData object
NSData *response = [NSURLConnection sendSynchronousRequest:request returningResponse:nil error:nil];

// Get JSON as a NSString from NSData response
NSString *json_string = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];

NSLog(@"string equal = %@", json_string);

// parse the JSON response into an object
// Here we're using NSArray since we're parsing an array of JSON b objects
NSArray *bathrooms = [parser objectWithString:json_string error:nil];

NSLog(@"count = %d", [bathrooms count]);

// Each element in bathrooms is a single bathroom
// represented as a NSDictionary
for (NSDictionary *bathroom in bathrooms)
{
    // You can retrieve individual values using objectForKey on the bathroom NSDictionary
    // This will print the tweet and username to the console
    NSLog(@"%@ - %@", [bathroom objectForKey:@"name"], [[bathroom objectForKey:@"lat"] objectForKey:@"long"]);
}

Answer 1

It’s because it’s not working. That’s not a valid JSON string. That’s 2 JSON dictionaries, back to back, with a comma in between. It’s missing the wrapping []. If you actually test the result value of -objectWithString:error:, you’d see it’s nil, and if you pass in an NSError** to the error parameter there, you’d get back an error message telling you it’s invalid JSON.