EXC_BAD_ACCESS，同时使用SBJSON解析JSON。 相应的消息状态变量json_string不是CFString

Question

I have the following response from server side:

{"_playLists":[{"name":"Playlist 1","items":[{"name":"Poza 1","target":"http:\/\/myaudi.fr","url":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/image\/pic1_iphone3.jpg","url_thumb":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/thumb\/pic1_iphone3_thumb.jpg"},{"name":"Poza 2","target":"http:\/\/audifrance.fr","url":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/image\/pic2_iphone3.jpg","url_thumb":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/thumb\/pic2_iphone3_thumb.jpg"}]},{"name":"Playlist 2","items":[{"name":"Poza 3","target":"http:\/\/google.ro","url":null,"url_thumb":null}]}]}

And I'm trying to acces this by using:

SBJSON *parser = [[SBJSON alloc] init];
NSString *responseString = [request responseString];

NSString *json_string = [[NSString alloc] initWithData:responseString encoding:NSUTF8StringEncoding];
NSArray *statuses = [parser objectWithString:json_string error:nil];

But I get EXC_BAD_ACCESS at this line

 NSString *json_string = [[NSString alloc] initWithData:responseString encoding:NSUTF8StringEncoding]; 

saying variable json_string is not a CFString .

Can someone help me solve this and tell me how to act further to acces the JSON components?Thank you:)

EDIT:

{
        items =         (
                        {
                name = "Poza 1";
                target = "http://myaudi.fr";
                url = "http://test.res-novae.fr/sfrplay/upload/image/pic1_iphone3.jpg";
                "url_thumb" = "http://test.res-novae.fr/sfrplay/upload/thumb/pic1_iphone3_thumb.jpg";
            },
                        {
                name = "Poza 2";
                target = "http://audifrance.fr";
                url = "http://test.res-novae.fr/sfrplay/upload/image/pic2_iphone3.jpg";
                "url_thumb" = "http://test.res-novae.fr/sfrplay/upload/thumb/pic2_iphone3_thumb.jpg";
            }
        );
        name = "Playlist 1";
    },
        {
        items =         (
                        {
                name = "Poza 3";
                target = "http://google.ro";
                url = "<null>";
                "url_thumb" = "<null>";
            }
        );
        name = "Playlist 2";
    }

Answer 1

You should use one of the JSON frameworks available out there, ie JSONKit or json-framework , which both makes it really easy to convert strings to JSON objects (ie an NSDictionary ).

If you're using json-framework, you'd only have to do the following (if you've included JSON.h ):

NSDictionary *jsonObject = [responseString JSONValue];

Answer 2

You do not need this line

NSString *json_string = [[NSString alloc] initWithData:responseString encoding:NSUTF8StringEncoding];

responseString is already a string (and initWithData: expects a NSData object not NSString). Just feed it straight to the parser:

NSArray *statuses = [parser objectWithString:responseString error:nil];

Can someone help me solve this and tell me how to act further to acces the JSON components?

You now have a nice NSArray of NSDictionary objects representing your JSON data, you can access the first item, represented by

{"name":"Playlist 1","items":[{"name":"Poza 1","target":"http:\/\/myaudi.fr","url":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/image\/pic1_iphone3.jpg","url_thumb":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/thumb\/pic1_iphone3_thumb.jpg"},{"name":"Poza 2","target":"http:\/\/audifrance.fr","url":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/image\/pic2_iphone3.jpg","url_thumb":"http:\/\/test.res-novae.fr\/sfrplay\/upload\/thumb\/pic2_iphone3_thumb.jpg"}]}

by getting the first element in the array

NSDictionary* dict = [statuses objectAtIndex:0];

and the keys in the dictionary should be "name", and "items". The object for "name" will be an NSString and the object for "items" will be an NSArray containing further NSDictionary objects describing each item.

Answer 3

There is a issue with your line

NSString *json_string = [[NSString alloc] initWithData:responseString encoding:NSUTF8StringEncoding];

you have declared responseString as NSString *responseString = [request responseString]; and you are giving it as Data while allocating json_string