Hi all so after a lot of hassle I managed to finally work my way around achieving and delimiting the JSON returned by Twitter Streaming APIs. How do i store the data returned by [NSJSONSerialization JSONObjectWithData:options:error:] into an array in appending
mode???
Here are the codes
To call the Streaming API
self.twitterConnection = [[NSURLConnection alloc] initWithRequest:signedReq delegate:self startImmediately: NO];
and in the delegate method (which is did receive data method)
NSError *parseError = nil;
self.dataSource=[NSJSONSerialization JSONObjectWithData:[string dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&parseError];
What i want to do is to store this NSJSONSerialized output in a static Array(preferably in append mode) so that i can pass it to table view for display. how do i go about it?
Thanks in Advance
EDIT
`self.dataSource1=[[NSMutableArray alloc]init];
NSString *string = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
string = [NSString stringWithFormat:#"[%#]", [string
stringByReplacingOccurrencesOfString:#"\r\n" withString:#","]];
NSError *parseError = nil;
self.dataSource =[NSJSONSerialization JSONObjectWithData:[string dataUsingEncoding:NSUTF8StringEncoding] options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&parseError];
[self.dataSource1 addObjectsFromArray:self.dataSource];`
Use -[NSMutableArray addObjectsFromArray:] to add objects to a mutable array.
Based on your comment, it looks like you're recreating self.dataSource1 every time you get data in didReceiveData. You should only create the object once before sending the request.
Related
What is the easiest way to write a JSON data/NSDictionary and read it back again? I know there's NSFileManager, but is there an open source framework library out there that would make this process easier? Does iOS5 NSJSONSerialization class supports writing the data to disk?
Yup, NSJSONSerialization is the way to go:
NSString *fileName = #"myJsonDict.dat"; // probably somewhere in 'Documents'
NSDictionary *dict = #{ #"key" : #"value" };
NSOutputStream *os = [[NSOutputStream alloc] initToFileAtPath:fileName append:NO];
[os open];
[NSJSONSerialization writeJSONObject:dict toStream:os options:0 error:nil];
[os close];
// reading back in...
NSInputStream *is = [[NSInputStream alloc] initWithFileAtPath:fileName];
[is open];
NSDictionary *readDict = [NSJSONSerialization JSONObjectWithStream:is options:0 error:nil];
[is close];
NSLog(#"%#", readDict);
It seems you must ensure that the directories in the path exist, otherwise your app will hang and consume 100% of your CPU when using + writeJSONObject:toStream:options:error:. The file itself will be created by the stream.
i have a problem parsing my json data for my iPhone app, I am new to objective-C. I need to parse the json and get the values to proceed. Please help. This is my JSON data:
[{"projId":"5","projName":"AdtvWorld","projImg":"AdtvWorld.png","newFeedCount":"0"},{"projId":"1","projName":"Colabus","projImg":"Colabus.png","newFeedCount":"0"},{"projId":"38","projName":"Colabus Android","projImg":"ColabusIcon.jpg","newFeedCount":"0"},{"projId":"25","projName":"Colabus Internal Development","projImg":"icon.png","newFeedCount":"0"},{"projId":"26","projName":"Email Reply Test","projImg":"","newFeedCount":"0"},{"projId":"7","projName":"PLUS","projImg":"7plusSW.png","newFeedCount":"0"},{"projId":"8","projName":"Stridus Gmail Project","projImg":"scr4.png","newFeedCount":"0"}]
On iOS 5 or later you can use NSJSONSerialization. If you have your JSON data in a string you can do:
NSError *e = nil;
NSData *data = [stringData dataUsingEncoding:NSUTF8StringEncoding];
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData: data options: NSJSONReadingMutableContainers error: &e];
Edit To get a specific value:
NSDictionary *firstObject = [jsonArray objectAtIndex:0];
NSString *projectName = [firstObject objectForKey:#"projName"];
I would recommend using JSONKit library for parsing.
Here's a tutorial on how to use it.
You will basically end up with a dictionary and use objectForKey with your key to retrive the values.
JSONKit
or
NSJSONSerialization(iOS 5.0 or later)
I have had success using SBJson for reading and writing json.
Take a look at the documentation here and get an idea of how to use it.
Essentially, for parsing, you just give the string to the SBJsonParser and it returns a dictionary with an objectForKey function. For example, your code might look something like:
NSDictionary* parsed = [[[SBJsonParser alloc] init] objectWithString: json];
NSString* projId = [parsed objectForKey:#"projId"];
Use SBJson
SBJsonParser *parser = [[SBJsonParser alloc] init];
NSMutableDictionary *dicRes = [parser objectWithString:stringFromServer error:nil];
No need to use third party classes. Objective-c already includes handling JSON.
The class NSJSONSerialization expects an NSData object or reads from a URL. The following was tested with your JSON string:
NSString *json; // contains your example with escaped quotes
NSData *jsonData = [json dataUsingEncoding:NSUTF8StringEncoding];
NSError *error;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:jsonData
options:NSJSONReadingAllowFragments error:&error]
For more options with NSJSONSerialization see the documentation.
I am having my server send me a list of all the images in a certain users folder, it sends me a string and i am using SBJsonparser to get it. here is the coding:
NSString *url = [[NSString alloc]initWithFormat:#"http://mysite.com/members/grabimages.php?&username=%#", [getLogin objectAtIndex:0]];
NSString *connect = [[NSString alloc]initWithContentsOfURL:[NSURL URLWithString:url]];
SBJsonParser *parser = [[SBJsonParser alloc]init];
NSString *imagenames = [[NSString alloc]init];
imagenames = [parser objectWithString:connect error:nil];
NSLog(#"%#", imagenames);
The string returns this:
(
"./username/default/img1.jpg",
"./username/default/img2.jpg"
)
There is going to be lots of URL's in this one string at some point, i want to be able to separate all the URL's and then add each one of them into a new string.
How would i be able to do this?
Thanks :)
the error from the other post error says the object was an NSMutableArray. presumably, that object was imagenames.
if so, then you declare it like so:
NSArray *imagenames = [parser objectWithString:connect error:nil];
then you use your relative base url to compose the url, as they are relative to some directory you must know of. so, you would compose the base (as an NSURL), and use one of the -[NSURL URLByAppending... methods to create new URLs from the elements of imagenames.
You could use NSArray *array = [imagenames componentsSeparatedByString:#","]; to separate the the urls
I'm working with facebook connect and trying to handle the JSON object that i'm receiving.
I invoked the requstWithGraphPath method and need to get back a JSON object,
tried to parse it and getting an error:
SBJSON *parser = [[SBJSON new] autorelease];
NSData *data = [[NSData alloc] initWithData:result];
NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; -> in this line - "[__NSCFDictionary length]: unrecognized selector sent to instance"
NSArray *events = [parser objectWithString:jsonString];
What's the problem?
Can I get the string in an other way or parse the object differently?
Thanks.
If you are working with the delegate callback
- (void)request:(FBRequest *)request didLoad:(id)result;
the parsing work has been done for you. Traverse the NSDictionary or NSArray to find the data you are looking for. If you are working with the delegate callback
- (void)request:(FBRequest *)request didLoadRawResponse:(NSData *)data;
you should initialize an NSString with the data, and use the category method that SBJSON adds to NSString for creating an id. That is assuming the data is data that constructs a string.
NSString *jsonString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
id result = [jsonString JSONValue];
Are you sure the error happens on that line, or does it happen on the line above?
If result is an NSDictionary (or CFDictionary, same thing), then it is already parsed and you do not need to do that yourself — and it could cause that error message too, on the line above.
The line:
data = [[NSData alloc] initWithData:result];
is almost certainly not what you want to do, as it is equivalent to
data = [result copy];
assuming that result is an NSData object (or NSMutableData), which I'm guessing it isn't.
I'm parsing an xml from an url, by
rssParser = [[NSXMLParser alloc] initWithContentsOfURL:xmlURL];
[rssParser parse]
How to NSLog it so as to see the xml in console??? If i use
NSLog ("%#",rssParser);
i'm showed wit 'XMLParser x 4d562' in the console
You should set parser's delegate and process retrieved xml data in its methods. See NSXMLParserDelegate protocol reference.
You can't. The NSXMLParser class never loads the entire contents of the XML stream in memory at once (that's why it's an "NSXMLParser" and not an "NSXMLDocument"). You should download the data from the URL, and use it to instantiate your RSS parser, and also to create an NSString that you log instead:
NSData *data = [NSData dataWithContentsOfURL:xmlURL];
rssParser = [[NSXMLParser alloc] initWithData:data];
NSString *string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSLog(#"data: %#", string);
[string release];
Please pay attention to the fact that the "initWithContentsOfURL:" methods are synchronous, and will block your UI thread until the data has downloaded. You might want to use ASIHTTPRequest or the NSURLConnection mechanism instead, with asynchronous connections.