I recently try to change the Json library in my applicaiton from SBJson to the NSJSONSerialization.
When I do this job, I find there are some key value that I can not get out.
Here is an example of the NSDictionary I get after NSJSONSerialization:
{
id = 4028;
"novel_author" = "XYZ";
"novel_pub" = "ABC";
"novel_title" = "DATE LIVE";
updatedate = "2013-01-13 22:31:13";
"vol_click" = 7563;
}
The original Json data string is:
{
"id":"4028",
"vol_click":"7563",
"updatedate":"2013-01-13 22:31:13",
"novel_author":"XYZ",
"novel_pub":"ABC",
"novel_title":"DATE LIVE"
}
I can not get the value of the key "id" out.
[NSDictionary objectForKey#"id"] is useless.
Is there anyone have idea how to get the value out?
As you can tell by the output of what looks like NSLog("%#", dict);, the JSON deserialization process works fine.
The dictionary contains a key called "id", so [dict objectForKey:#"id"] should also work fine.
I can only conclude that this isn't the actual cause of the trouble you're having.
Either of these should work:
[yourDictName valueForKey:#"id"]
[yourDictName objectForKey:#"id"]
If you can see the value using NSLog to display the dictionary, then it is there. Beyond that, make sure your object is not getting nil'd or released or freed.
Related
So I am building an app that uses parse as a backend. I've written my own before but I figured I'll just save some time and use parse. I'm populating a table view with data from parse and that's fine. I want to grab the objectId from an dictionary built from an array from parse.
The output of my array is as follows:
<news_events:pdbIEvOteH:(null)> {\n eventDescription = \"This is a test description.\";\n eventMessage = \"This is a test message.\";\n eventTitle = \"Free Wi-Fi Now Available!\";\n}
The object ID is pdbIEvOteH in the example above. I at first tried getting the id by using:
NSString * objectId = [myDictionary objectForKey:#"objectId"]; But that returned null. I know it is not a problem with my dictionary because I can get other information. The problem is it looks like there is no key for objectId in the array above. As you can see it follows news_events.
I know you can get it with the PFObject but I'm not sure if I can populate a table with a PFObject.
So bottom line is how do I get the objectId.
In my didSelectRowAtIndexPath: method, I did the following:
PFObject *myObject = [parseArray objectAtIndex:indexPath.row];
NSString *objectId = [myObject objectId];
To get the Id of a particular PFObject.
In Swift:
var objectId = object.objectId
In Objective-C:
NSString *objectId = object.objectId;
"So bottom line is how do I get the objectId."
following is answer from 'Joe Blow' with actual/example code for ios.
i had similar issue. retrieving data with following code worked:
NSString *reporterOpinion = [NSString stringWithFormat:#"%#", [object objectForKey:#"reporterOpinion"]];
but trying to do objectForKey with objectId returned null:
NSString *objectId = [NSString stringWithFormat:#"%#", [object objectForKey:#"objectId]];
following 'Joe Blow' answer, the following code returned correct value for objectId:
NSString *objectId = object.objectId;
I am using the following JSON: http://www.kb.dk/tekst/mobil/aabningstider_en.json
When I try to parse it by the key "location" as such:
// get response in the form of a utf-8 encoded json string
NSString *jsonString = [[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
// get most parent node from json string
NSDictionary *json = [jsonString JSONValue];
// get key-path from jason up to the point of json object
NSDictionary *locations = [json objectForKey:#"location"];
NSLog( #"%#", locations );
// iterate through all of the location objects in the json
for (NSDictionary *loc in locations )
{
// pull library name from the json object
NSString *name = [loc valueForKey:#"name"];
// add library data table arrays respectively
[ libraryNames addObject: ( ( name == nil | name.length > 0 ) ? name : #"UnNamed" ) ];
}
When I print the the object locations via NSLog:
{
address = "Universitetsparken 4, 3. etage, 2100 K\U00f8benhavn \U00d8";
desc = "";
lastUpdated = "";
latlng = "55.703124,12.559596";
link = "http://www.farma.ku.dk/index.php?id=3742";
name = "Faculty of Pharmaceutical Sciences Library";
parts = {
part = {
hour = {
day = "5.June Constitution Day (Denmark)";
open = Closed;
};
hours = {
hour = {
day = Friday;
open = "10-16";
};
};
name = main;
};
};
}
Which is only the last value for the "location" keys. Am I doing something wrong?
I tried validating the JSON via http://jsonlint.com/, however when I'd put in the JSON URL as above, it said "valid" - still only the last "locations" key was shown", however if I copy-paste it, it will not validate the JSON, and has to be fixed by removing new-lines from the string.
Also, when i try to parse the JSON and get the "name" fields, I get the following exception:
2012-05-08 15:37:04.941 iPhone App Tabbed[563:f803] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFString 0x68bfe70> valueForUndefinedKey:]: this class is not key value coding-compliant for the key name.'
*** First throw call stack:
(0x13dc052 0x156dd0a 0x13dbf11 0x9d2f0e 0x941841 0x940ca9 0x4593 0xf964e 0x114b89 0x1149bd 0x112f8a 0x112e2f 0x1148f4 0x13ddec9 0x365c2 0x3655a 0x25b569 0x13ddec9 0x365c2 0x3655a 0xdbb76 0xdc03f 0xdbbab 0x25dd1f 0x13ddec9 0x365c2 0x3655a 0xdbb76 0xdc03f 0xdb2fe 0x5ba30 0x5bc56 0x42384 0x35aa9 0x12c6fa9 0x13b01c5 0x1315022 0x131390a 0x1312db4 0x1312ccb 0x12c5879 0x12c593e 0x33a9b 0x281d 0x2785)
terminate called throwing an exception(lldb)
It would make more sense if the "locations" tag was an array object enclosed by square brackets ([]), however right now it's only an sequence of normal key-value pairs... Sadly, that's the JSON I have to work with.
Please help and thanks a great deal! :)
Sincerely,
Piotr.
The JSON you've got to work with may be valid, but it doesn't make much sense. It has one big dictionary with the location key repeated many times. Most JSON parser will simply return the last value for the repeated key. It would be best if you could change the structure to use an array instead, but if you cannot there's still hope. You can read the stream and stuff the values from the location keys into an array as they come out of it. This is how you'd do that:
#interface BadJsonHelper : NSObject
#property(strong) NSMutableArray *accumulator;
#end
#implementation BadJsonHelper
- (void)parser:(SBJsonStreamParser *)parser foundArray:(NSArray *)array {
// void
}
- (void)parser:(SBJsonStreamParser *)parser foundObject:(NSDictionary *)dict {
[accumulator addObject:dict];
}
#end
You can drop that little helper class at the top of your file, outside the #implementation section of the class where you're doing your work. (There's no need for the #interface and #implementation being in different files.)
In your code, you would use it like this:
BadJsonHelper *helper = [[BadJsonHelper alloc] init];
helper.accumulator = [NSMutableArray array];
SBJsonStreamParserAdapter *adapter = [[SBJsonStreamParserAdapter new] init];
adapter.delegate = helper;
adapter.levelsToSkip = 1;
SBJsonStreamParser *parser = [[SBJsonStreamParser alloc] init];
parser.delegate = adapter;
switch ([parser parse: responseData]) {
case SBJsonStreamParserComplete:
NSLog(#"%#", helper.accumulator);
break;
case SBJsonStreamParserWaitingForData:
NSLog(#"Didn't get all the JSON yet...");
break;
case SBJsonStreamParserError:
NSLog(#"Error: %#", parser.error);
break;
}
This example was originally adapted from the following test:
https://github.com/stig/json-framework/blob/master/Tests/StreamParserIntegrationTest.m
Update: I created a fully functional example project that loads the JSON asynchronously and parses it. This is available from github.
The JSON is valid, however there is a basic problem regarding the definition of the array of items.
Instead of defining an array of locations using brackets, the JSON redefines the same location key/value pair over and over again. In other words JSON initially says the value of location is the collection with name "The Black Diamond", but immediately after it redefines it with the collection with name "Faculty Library of Humanities" and so on till the last location Faculty of Pharmaceutical Sciences Library".
The same is true for parts and hours.
If you can't fix the result of the JSON and you really need to get it working you may want to modify the JSON removing the "location" keys and adding brackets properly.
Edit
Alternatively you may use an NSScanner and process the JSON result manually. Kinda hacky but it will work as long as the JSON format doesn't change significantly.
Edit
This snipped of code should do the work...
NSString *jsonString = [[[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
int indx = 1;
for (;;)
{
NSRange locationRange = [jsonString rangeOfString:#"\"location\":"];
if (locationRange.location == NSNotFound) break;
jsonString = [jsonString stringByReplacingCharactersInRange:locationRange
withString:[NSString stringWithFormat:#"\"location%d\":", indx++]];
}
NSDictionary *locations = [json objectForKey:#"location"];
As you can see, the result of JSON parsing by SBJson is a NSDictionary. A dictionary contains key/value pairs, and the keys are unique identifiers for the pairs.
The JSON data you need to handle is valid but not a good one. Per RFC 4627 - 2.2:
An object structure is represented as a pair of curly brackets surrounding zero or more name/value pairs (or members). A name is a string. A single colon comes after each name, separating the name from the value. A single comma separates a value from a following name. The names within an object SHOULD be unique.
Things like jQuery can parse the JSON also, but the result is the same as SBJson (the last one as the one). See Do JSON keys need to be unique?.
It is not a MUST, but it's still not a good practice. It would be much easier if you are able to change the structure of the JSON data on the server side (or even on the client side after receiving it) rather than parsing it as is.
I'm sorry for this (probably very) noob question, but i've been asked about this and can't see what's wrong (i'm java tought..)
This is what I have, data is loaded via JSON:
NSDictionary *myvalues = [myres objectForKey:#"0"];
this is the content if I output via NSLog:
({id = "1a";myval = 5;},
{id = "2b";myval="24.6";})
how do I iterate through myvalues and how do I get the values id and myval? Something like this i'm getting stuck:
for (NSArray* myvals_array in myvalues)
First it looks like the returned value is an Array, the content inside of the parentheses() denotes this. So I would try and set it as such instead of a Dictionary. Then you can enumerate through the array of dictionary's and get each dictionary inside:
for (id object in myvalues) {
NSDictionary *currentObject = (NSDictionary*)object;
NSString *myID = [currentObject valueForKey:#"id"];
NSString *myValue = [currentObject valueForKey:#"myval"];
NSLog(#"ID:%# VALUE:%#",myID,myValue);
}
This will enumerate through the array and create a dictionary for each entry, then get the values for each of the two elements inside. I just NSLog() them here but you can do whatever you want with the values.
I have one genuine question which I am facing at this point and I am sure someone might be able to help me.
I have a JSON Post which looks like:
{
"CustomerAccount":{
"CustomerUID":"String content",
"UserName":"String content",
"Password":"String content",
"OldPassword":"String content",
"Email":"String content",
"QuestionUID":2147483647,
"QuestionAnswer":"String content",
"EAlerts":true
}
}
Now I have a dictionay which set's value of CustomerUID, UserName, etc.. Now if I want to bind a upper level to bind all that to CustomerAccount and send as my JSONRepresentation, is there any easier way than actually creating a new dictionary and setting a value of key "CustomerAccount" in this example? I am sure there might be a better way of doing that.
Thanks.
Not entirely sure I follow, but is this what you want maybe:
NSDictionary *dictA = <dictionary_with_customeruid_etc>;
NSDictionary *customerAccountDict = [NSDictionary dictionaryWithObjectsAndKeys:dictA, #"CustomerAccount", nil];
But I'm not sure I follow your question entirely so maybe you want something else. Please let us know a bit more about what you're trying to do.
I don't really understand your question but ill give it a try.
You can easily parse the JSON string to a NSDictionary using JSONKit https://github.com/johnezang/JSONKit
JSONKit is a very fast and lightweight library and you can parse the string and get the wanted value like this:
NSDictionary *dict = [jsonString objectFromJSONString];
NSString *value = [dict valueForKey:#"key"];
To actually set a value in your JSON string you should use rangeOfString: .location to get the range if the existing value then replaceOccurenciesOfString:[jsonString substringWithRange:NSMakeRange(loc,len)] withString:VALUE.
I'm quite new to iphone programming and I want to do the following stuff:
get data from a JSON REST web server
parse the received data using YAJL
Draw a graph with those data using core-plot
So, 1th item is fine, I use ASIHttpRequest which runs as espected
3rd is almost fine (I still have to learn how to tune core-plot).
The problem I have is regarding 2nd item.
I use YAJL as it seems to be the faster parser, so why not give it a try :)
Here is the part of code that gets the data from the server and parse them:
// Get server data
response_data = [request responseData];
// Parse JSON received
self.arrayFromData = [response_data yajl_JSON];
NSLog(#"Array from data: %#", self.arrayFromData);
The parsing works quite well in fact, the NSLog output is something like:
2010-06-14 17:56:35.375 TEST_APP[3733:207] Array from data :
{
data = (
{
val = 1317;
date = "2010-06-10T15:50:01+02:00";
},
{
val = 1573;
date = "2010-06-10T16:20:01+02:00";
},
........
{
val = 840;
date = "2010-06-11T14:50:01+02:00";
},
{
val = 1265;
date = "2010-06-11T15:20:01+02:00";
}
);
from = "2010-06-10T15:50:01+02:00";
to = "2010-06-11T15:20:01+02:00";
max = "2590";
}
According to th yajl-objc explanations http://github.com/gabriel/yajl-objc, the parsing returns a NSArray...
The thing is... I do not know how to get all the values from it as for me it looks more like a NSDictionary than a NSArray...
Could you please help ?
Thanks a lot,
Luc
edit1: it happens that this object is actually a NSCFDictionary (!), I am still not able to get value from it, when I try the objectFromKey method (that should work on a Dictionary, no ?) it fails.
It's returning an NSDictionary. NSCFDictionary is a private subclass and is immaterial to this discussion. So it looks like you'd retrieve stuff like:
NSDictionary * responseDictionary = ...;
NSArray * dataArray = [responseDictionary objectForKey:#"data"];
for (NSDictionary * dataPair in dataArray) {
NSLog(#"val: %#, date: %#", [dataPair objectForKey:#"val"], [dataPair objectForKey:#"date"]);
}