问题
I have the following JSON object:
{
"response": {
"status": 200
},
"messages": [
{
"message": {
"user": "value"
"pass": "value",
"url": "value"
}
]
}
}
I am using JSON-Framework (also tried JSON Touch) to parse through this and create a dictionary. I want to access the "message" block and pull out the "user", "pass" and "url" values.
In Obj-C I have the following code:
// Create new SBJSON parser object
SBJSON *parser = [[SBJSON alloc] init];
// Prepare URL request to download statuses from Twitter
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:myURL]];
// 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];
//Print contents of json-string
NSArray *statuses = [parser objectWithString:json_string error:nil];
NSLog(@"Array Contents: %@", [statuses valueForKey:@"messages"]);
NSLog(@"Array Count: %d", [statuses count]);
NSDictionary *results = [json_string JSONValue];
NSArray *tweets = [[results objectForKey:@"messages"] objectForKey:@"message"];
for (NSDictionary *tweet in tweets)
{
NSString *url = [tweet objectForKey:@"url"];
NSLog(@"url is: %@",url);
}
I can pull out "messages" and see all of the "message" blocks, but I am unable to parse deeper and pull out the "user", "pass", and "url".
回答1:
Solved:
NSArray *tweets = [[results objectForKey:@"messages"] valueForKey:@"message"];
回答2:
Array({
0=>Dictionary({
response = Array({
0=>Dictionary(Status = 200)
})
}),
1=>Dictionary({
messages = Array({
0=> Dictionary({
message = Array({
0=>Dictionary({
user = value,
pass=value,
url=value
})
})
})
})
})
})
So, to access dictionary for user, pass, url,
nsarray *arr = jsonmainarray;
arr = [[[jsonmainarray objectAtIndex: 1] objectforkey:@"messages"] objectatindex: 0];
nsdictionary *dict = [arr objectatindex: 0];
arr = [dict objectforkey:@"message"];
dict = [arr objectatindex: 0]; // Dictionary with user, pass, url
回答3:
there is an easier way (in my opinion) to do JSON parsing :)
- (void)loadJSONData:(NSString *)u{
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"http://expandurl.appspot.com/expand?url=%@", u]];
NSData *rawJsonData = [NSData dataWithContentsOfURL:url];
CJSONDeserializer *parser = [CJSONDeserializer new];
NSError *error;
NSDictionary *jsonDictionary = [parser deserializeAsDictionary:rawJsonData error:&error];
[parser release];
NSArray *array = [jsonDictionary objectForKey:@"urls"];
}
All you have to do is to use JSON touch... like Sheehan Alam mention.
Say that you got this line of JSON data:
{ "end_url" = "http://www.youtube.com"; redirects = 0; "start_url" = "http://www.youtube.com"; status = OK; urls = ( "http://www.youtube.com" ); }
then in your JSONDictonary the data can be accessed by doing:
[jsonDictionary objectForKey:@"urls"]; //This will return an Array since URLS is a array
[jsondictionary objectForKey:@"en_url"]; //this will return an NSString since end_url is a string
Hope this help people as much as it helped me =)
sincerely yours Kristian
来源：https://stackoverflow.com/questions/2414426/parsing-nested-json-objects-with-json-framework-for-objective-c