I'm a bit stuck in a project.
I was writing some code to get a JSON file and store it in an NSString before parsing it into a NSArray.
But I get an error:
2010-10-27 20:59:44.813 GeraldKervyn[21752:207] -JSONValue failed. Error trace is: (
"Error Domain=org.brautaset.JSON.ErrorDomain Code=3 \"Unrecognised leading character\" UserInfo=0x7637890 {NSLocalizedDescription=Unrecognised leading character}"
I think the problem is related to the limited value that an NSString can take.
BTW this is the feed I'm using : http://www.geraldkervyn.com/api/get_recent_posts/
What would be the most convenient way to parse this into an NSArray ?
Thanks !
First, Add the SBJson code to your project, courtesy of Stig Brautaset. Then do this...
NSString *subject = #"http://www.geraldkervyn.com/api/get_recent_posts/";
NSString *encodedSubject =
[subject stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSString *test = [NSString stringWithContentsOfURL:[NSURL URLWithString:encodedSubject]];
SBJsonParser *parser = [[SBJsonParser new] autorelease];
NSDictionary *json = [parser objectWithString:test];
NSArray *values = [json objectForKey:#"posts"];
Related
I have an application in which I am having a json response like this.
{"success":"true","message":"You have logged in","pserial":"1"} and I am separating with ":".
And I am getting data like this pSerial:"1"} but I want only 1 value.
NSURL *url = [NSURL URLWithString:strUrl];
NSData *respData = [NSData dataWithContentsOfURL:url];
NSString *strResp = [[NSString alloc]initWithData:respData encoding:NSUTF8StringEncoding];
NSString *approvalString = [[strResp componentsSeparatedByString:#":"] objectAtIndex:3];
NSLog(#"pSerial:%#",approvalString);
for Example :
SBJsonParser *jsonPar = [[SBJsonParser alloc] init];
NSError *error = nil;
NSArray *jsonObj = [jsonPar objectWithString:jsonString error:&error];
id jsonObj = [jsonPar objectWithString:jsonString error:&error];
if ([jsonObj isKindOfClass:[NSDictionary class]])
// treat as a dictionary, or reassign to a dictionary ivar
else if ([jsonObj isKindOfClass:[NSArray class]])
// treat as an array or reassign to an array ivar.
Then get the value :
NSMutableArrary *userMutArr = [NSMutableArray array];
for (NSDictionary *dict in jsonObj)
{
User *userObj = [[[User alloc] init] autorelease];
[userObj setFirstName:[dict objectForKey:#"firstName"]];
[userObj setLastName:[dict objectForKey:#"lastName"]];
[userObj setAge:[[dict objectForKey:#"age"] intValue]];
[userObj setAddress:[dict objectForKey:#"address"]];
[userObj setPhoneNumbers:[dict objectForKey:#"phoneNumber"]];
[userMutArr addObject:userObj];
}
Hope you will understand. and read some Documents. it will help you.
It looks like you are in need of JSON Parsing. Here, what you want is JSON Parsing, not separating data from the JSON Response. JSON is the format of the data in which data is formatted in Key-Value pairs. You can fetch the "Value" of any object using the "Key".
Your first two lines are correct.
NSURL *url = [NSURL URLWithString:strUrl];
NSData *respData = [NSData dataWithContentsOfURL:url];
Now, you can parse JSON Response like this :
NSError* error;
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:respData options:kNilOptions error:&error];
NSString *pSerial = [json objectForKey:#"pserial"];
This will give you the value of "pserial" from your response. Similarly, you can get the values for "success" and "message". You can check it using this line :
NSLog(#"pserial :: %#",pserial);
You need to parse the JSON Response String, you can use any JSON parser like:
https://github.com/stig/json-framework/
And in your code do:
NSString *strResp = [[NSString alloc]initWithData:respData encoding:NSUTF8StringEncoding];
NSDictionary *ResponseDictionary = [strResp JSONValue];
NSString * pSerial = (NSString*)[ResponseDictionary objectForKey:#"pserial"];
Dont separation by ":" just use JSONValue your response is like
// {"success":"true","message":"You have logged in","pserial":"1"}
// with SBJsonParser parse your object like this
NSDictionary *responseJson = [YOUR-OBJECT JSONValue];
Note: dont forget to add Json header file
Its better you use any OpenSource Json Parser
Here is a stack post Comparison of different Json Parser for iOS
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 implementing SBJSON to fetch the data from web service. My code in "ConnectionDidFinishLoading" is as follows:
NSString *responseString = [[NSString alloc] initWithData:responseData encoding: NSUTF8StringEncoding];
NSLog(#"Response String %#", responseString);
NSDictionary *results = [responseString JSONValue];
NSString *extractUsers = [results objectForKey:#"d"];
NSDictionary *finalResult = [extractUsers JSONValue];
NSLog(#"Final Results : %#",finalResult);
But I got the error msg in my console as follows:
-JSONValue failed. Error trace is: (
"Error Domain=org.brautaset.JSON.ErrorDomain Code=3 \"Unrecognised leading character\" UserInfo=0x686d010
{NSLocalizedDescription=Unrecognised leading character}" )
I have referred several links on stackoverflow and I also use google to find the answer but I am not able to get the solution
If you have solution then share it with me.
Thanx in advance...
first u have to call the selector.
DownloadManager *mgr= [[DownloadManager alloc] sharedManager:self:#selector(downloadVideos:)];// initialize your class where u write all the methods
[mgr downloadVideos]; // call method where u send request to particular url
[mgr autorelease];
than
-(void)downloadVideos:(NSMutableData*)data{
NSString *responseString = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
NSDictionary *parseDict = (NSDictionary*)[responseString JSONValue];
NSLog(#"%#",parseDict);
}
I just had this problem and it turned out to be that the permissions on the directory used by the web service had been changed.
So browse to the WS or try another means of accessing it to make sure it's up.
I have upgraded from XCODE 4 to 4.2 and now i have problems.
The following code worked pre 4.2 to read the file in "filePath":
// Fill myString with questions from the .txt file and then read .txt file
NSString *filePath = whatFile;
NSString *myString = [[NSString alloc] initWithContentsOfFile:filePath];
// Load array
NSArray* myArray = [myString componentsSeparatedByString:#"\r"];
NSLog (#"\n \n Number of elements in myArray = %i", [myArray count]);
With 4.2 the "initWithContentsOfFile" in the following code line is deprecated:
NSString *myString = [[NSString alloc] initWithContentsOfFile:filePath];
...and should be replaced with the below according to the manual:
NSString *myString = [NSString stringWithContentsOfFile:filePath encoding: NSUTF8StringEncoding error:&err];
and i can not get this to read the records in the same file by replacing the code line. BTW, i have defined the &err.
When i NSLog myString i get (null).
I am getting a bit desperate to solve this and would very much appreciate any help.
Cheers
NSLog the err variable if there is an error. Also NSLog filePath.
Perhaps the encoding is not UTF-8, are you sure about the encoding?
The best non-UTF-8 encoding bet is NSMacOSRomanStringEncoding which supports 8-bit characters.
Try :
NSError* error = nil;
NSStringEncoding encoding;
NSString *fileContent = [NSString stringWithContentsOfFile:filePath usedEncoding:&encoding error:&error];
If that does not works, try in your code : NSASCIIStringEncoding
The file probably doesn't contain a UTF8 encoded string. See apple's documentation, which has an example of reading a file where you do not know the encoding: Reading data with an unknown encoding
You need to use the [string|init]WithContentsOfFile:usedEncoding:error method, and if that fails there are a few more things you can try before finally presenting an error message to the user (for example, try reading it as an NSAttributedString).
For example, you could do this:
// Fill myString with questions from the .txt file and then read .txt file
NSString *filePath = whatFile;
NSStringEncoding encoding;
NSError *error;
NSString *myString = [[NSString alloc] initWithContentsOfFile:filePath usedEncoding:&encoding error:&error];
if (!myString) {
myString = [[NSString alloc] encoding:NSUTF8StringEncoding error:&error]
}
if (!myString) {
myString = [[NSString alloc] encoding:NSISOLatin1StringEncoding error:&error]
}
if (!myString) {
NSLog(#"error: %#", error);
return;
}
// Load array
NSArray* myArray = [myString componentsSeparatedByString:#"\r"];
NSLog (#"\n \n Number of elements in myArray = %i", [myArray count]);
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.