cannot parse json string into nsdictionary - iphone

Question

Im trying to parse a json string using sbjsonparser. Im having trouble converting it to nsdictionary. I've used sbjsonparser in my other classes and they all worked fine. see my code.
-(void)parseJsonString
{
NSLog(#"%#",jsonString);
SBJsonParser *parser = [[SBJsonParser alloc] init];
NSDictionary *dict;
dict = [parser objectWithString:jsonString error:nil];
NSLog(#"%#",dict);
NSDictionary *dict2;
dict2 = [jsonString JSONValue];
NSLog(#"%#",dict2);
[parser release];
}
here's my console output:
2011-08-12 13:56:55.098 EasyQuiz[5446:13603] [{
"q": "Question Testing",
"score": 1,
"c3": "Choice C",
"c2": "Choice B",
"c1": "Choice A",
"rev": 1,
"id": 1,
"c4": "Choice D"
}]
2011-08-12 13:56:55.686 EasyQuiz[5446:13603] (null)
2011-08-12 13:56:56.296 EasyQuiz[5446:13603] -JSONValue failed. Error is: Illegal start
of token []
2011-08-12 13:56:56.297 EasyQuiz[5446:13603] (null)
I checked the string at http://jsonformatter.curiousconcept.com/ and it appears to be valid. what do you think is causing this problem? thanks!
I printed the error in dict = [parser objectWithString:jsonString error:nil]; and it says:
Error Domain=org.brautaset.SBJsonParser.ErrorDomain Code=0 "Illegal start of token []"
UserInfo=0x62eb920 {NSLocalizedDescription=Illegal start of token []}
EDIT
I tried hardcoding the jsonstring like this
NSString *thisJsonString = #"[{\"q\": \"Question Testing\",\"score\": 1, \"c3\": \"Choice C\", \"c2\": \"Choice B\", \"c1\": \"Choice A\", \"rev\": 1, \"id\": 1, \"c4\": \"Choice D\"}]";
SBJsonParser *parser = [[SBJsonParser alloc] init];
NSDictionary *dict;
dict = [parser objectWithString:thisJsonString error:nil];
NSLog(#"dict %#",dict);
[parser release];
and I got what I want in the console:
dict (
{
c1 = "Choice A";
c2 = "Choice B";
c3 = "Choice C";
c4 = "Choice D";
id = 1;
q = "Question Testing";
rev = 1;
score = 1;
}
)
EDIT
In case you want to know where I get the data. I downloading a zip file from a website using asihttprequest and the this file is extracted using objective-zip and the extracted file is read like this.
NSString *filePath = [[self applicationDocumentsDirectory]
stringByAppendingPathComponent:#"json.zip"];
//Opening zip file for reading...
progressLabel.text = #"Reading file...";
ZipFile *unzipFile= [[ZipFile alloc] initWithFileName:filePath mode:ZipFileModeUnzip];
//Opening first file...
progressLabel.text = #"Opening file...";
[unzipFile goToFirstFileInZip];
ZipReadStream *read1= [unzipFile readCurrentFileInZip];
//Reading from first file's stream...
NSMutableData *data1= [[[NSMutableData alloc] initWithLength:1000000] autorelease];//100MB
int bytesRead1= [read1 readDataWithBuffer:data1];
NSLog(#"bytes: %d",bytesRead1);
if (bytesRead1 > 0) {
progressLabel.text = #"File is good!";
jsonString = [[[NSString alloc] initWithData:data1 encoding:NSUTF8StringEncoding] autorelease];
//.... more codes follow, but this is how I get jsonString

Answer 1

Your json is an array of one object, so you can't directly parse it to NSDictionary. First parse it to NSArray and then take first object and put it into a NSDictionary
-(void)parseJsonString
{
NSArray *jsonArray = (*NSArray)[jsonString JSONValue];
NSDictionary *jsonDict = [jsonArray objectAtIndex:0];
NSString *q = [jsonDict objectForKey:#"q"];
...
}

Answer 2

objectWithString:error: is having return type id, modify your code as below and let me know.
NSString *str = [NSString stringWithFormat:#"%#", [parser objectWithString:jsonString error:nil]];
NSDictionary *dict = [[NSDictionary alloc] initWithObjectsAndKeys:str,#"response", nil];
NSLog(#"%#",[dict description]);