I need to put an array of JSON objects into a new JSON object.
{“megaObject”:[
{ “key”:8,
“key2”:”val”
},
{ “key”:5,
“key2”:”val”
},
{ “key”:6,
“key2”:”val”
}
]
}
I have created the array like this:
NSArray *myArray = #[NSData json1, NSData json2, NSData json3];
Is this the correct way to make a JSON array and if so, how can I put it as a value to key `megaObject.'
I'm new to iOS development so any help is great.
If you represent the JSON object as a NSDictionary, you can simply use the methods of this. I.e.
NSDictionary *jsonDict1;
NSDictionary *jsonDict2;
NSDictionary *jsonDict3;
NSArray *resultAry = #[jsonDict1, jsonDict2, jsonDict3];
NSDictionary *resultDict = #{#"megaObject" : resultAry};
and from here on convert to NSData or anything else you need ;) First understand what classes you are working with and then look at their methods in the API. Investigate more and concentrate your questions on things that you couldn't solve after at least 2 hours investigation ;)
UPDATE
taking a look at your structure...
{"megaObject": // <-- NSDictionary "resultDict" with the key "megaObject" and NSArray "resultAry" with 3 NSDictionaries as value.
[
{ // NSDictionary "jsonDict1" with 2 entries.
“key”:8,
“key2”:”val”
},
{ “key”:5, // and so on
“key2”:”val”
},
{ “key”:6,
“key2”:”val”
}
]
}
I would use NSJSONSerialization, from the documentation:
You use the NSJSONSerialization class to convert JSON to Foundation objects and convert Foundation objects to JSON.
Not sure what you want to reach as result, but this example can help you undersand how to assign an array as value into a NSDictionary as key.
NSDictionary *NEWjSON= [[NSDictionary alloc]init];
NSArray *myArray = #[
#{
#"key" : #"8",
#"key2" : #"val",
},
#{ #"key" : #"5",
#"key2":#"val",
},
#{ #"key":#"6",
#"key2":#"val"
}
];
[NEWjSON setValue:myArray forKey:#"megaObject"];
Related
So I was working on a project that required me to work with some JSON, I was running into a few issues regarding the best way of representing things. First of, this is how the JSON looks:
"phoneList": [
{
"phoneReason": "End of Contract",
"phoneType": [
{
"id": 5,
"phoneType": "Android Smartphone"
}
]
}
]
I want to know the most appropriate way of representing this.
For example, I do know that that my phoneReason will just be a simple NSString while my phoneType is actually a NSArray. However,I wasn't sure how to represent a)the id, I know this is an integer, but should this be an NSInteger or an NSNumber and b)could someone point me in the direction of some sample code where I can understand how to model a dictionary object containing an integer and a string and also where I can understand how to model an array of dictionaries.
My other question is also similar in that say I'm actually posting something, how do I model this, specifically say for like dictionary type (JSON Curly Brace)objects that contain a number/integer and a string.
For example, this is the JSON I'm trying to model and then do something like this:
"phoneReason": "Upgrade",
"phoneInfo": {
"id": "2"
},
//And then I want to pass ID
-(void) createOurRequest:(NSNumber *)id {
NSDictionary *myDictionary = #{
#"phoneReason" : [NSString stringWithFormat:#"%i", s elf.dat.reason],
//How do I then represent the phoneInfo element exactly?
};
Sorry, for the clumsy question, would really appreciate any guidance on modeling JSON in iOS or just generally.
I'm assuming you're asking questions a) and b), and also how to model a JSON.
a) The unfortunate thing with Obj-C is that all collection elements have to be objects. Integers are value types, so they will need to be converted to NSNumbers to work. However, if you're parsing a JSON string, the builtin JSON parser does it for you. I'll describe it below.
b) The model is based on the JSON. You describe the object collection and the parser will determine the model for you. In your example, you would have a NSDictionary<NSString *: NSArray<NSDictionary<NSString *: id>*>*>. The innermost element has value of id because you can either have an NSString ("End of Contract") or an NSArray ("phoneType": [ { "id": 5, "phoneType": "Android Smartphone" } ])
Of course, the model is defined by your JSON, so if you run it through a parser, you get a structured object. You can access each element based on your model (object[#"phoneList"][#"phoneReason"]).
The class method to use is:
+ (id)JSONObjectWithData:(NSData *)data
options:(NSJSONReadingOptions)opt
error:(NSError **)error
Where you pass it a NSData representation of your string, options (or 0), and a NSError pointer (error*). You get back a parsed JSON with the proper structure you defined.
NSDictionary *parsedJSONObject = [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:NULL
I have no options to use and I know there will be no error, so I pass nothing for those parameters. The resulting object will be in whatever structure your JSON is.
Using the objects and the json layout you provided in your first example, this is how I would go about creating the dictionaries and arrays to get the json in the format you specified. Hopefully this helps make it a little clearer for you.
// example constructor method
-(void) jsonStringWithPhoneReason:(NSString*)reason phoneId:(NSInteger)phoneId phoneType:(NSString*)phoneType
{
// create device detail dictionary
NSDictionary *deviceOneDetail = #{
#"id" : #(phoneId), // <- set phone id as NSNumber
#"phoneType" : phoneType // <- set your string phone type
};
// create device dictionary
NSDictionary *deviceOne = #{
#"phoneReason" : reason, // <- set your phone reason string
#"phoneType" : #[deviceOneDetail] // <- set your phone type dictionary within an array
};
// create phone list dictionary with any device dictionaries you want to add
NSDictionary *phoneListDict = #{
#"phoneList" : #[
deviceOne, // <- add your device to the phone list array of dictionaries
// deviceTwo...
]
};
NSString *jsonString = [self convertToJsonString:phoneListDict]; // <- convert the dictionary into a json string and use however you wish
// your json string should now look like this assuming you pass 'End of Contract', 5 & 'Android Smartphone' as arguments to this method
// {"phoneList":[{"phoneReason":"End of Contract","phoneType":[{"id":5,"phoneType":"Android Smartphone"}]}]}
}
-(NSString*) convertToJsonString:(NSDictionary*)dictionary
{
NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dictionary
options:0 // Pass 0 if you don't care about the readability of the generated string
error:&error];
if (error)
{
NSString *errorDesc = [NSString stringWithFormat:#"Error creating json data from dictionary: %#", error.localizedDescription];
NSLog(#"ERROR: %#", errorDesc);
jsonData = nil;
return nil;
}
NSString *returnString = nil;
if(jsonData != nil)
{
returnString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}
return returnString;
}
I try to send data to the server. Server waits from my this structure among other:
{
...
"card": [
{
"child": {...},
"parent":{...}
},
{
"child": {...},
"parent":{...}
}
],
[...],
[...]
}
So it should be Dictionary ({...}) placed into another Dictionary ({"child":..., "parent":...}), placed into an Array ("card": []), and this array is a cell, the final API JSON contains many of such cells.
I realize this structure by something like this:
NSDictionary *card = #{#"key1" : #"val1", #"key2" : #"val2", #"key3" : #"val3"};
NSDictionary *pair = #{#"parent" : card, #"child" : card};
NSArray *cards = [NSArray arrayWithObjects: pair, pair, nil];
After this I add cards Array into Dictionary with other auth data and send it to the server:
[self.userAuthData setObject: cards forKey:#"card"];
And I see in the server logs that data was shredded: http://monosnap.com/image/UbLPA0AK0eotAvG12o1ML4702xy0aj.png
But, if I use Dictionary cards instead of Array cards, everything is ok: http://monosnap.com/image/IzenpFc3Gik01UYhyRYtGFHmxBpCpC.png
What's wrong with idea to store Dictionary in an Array? Why it gets shredded?
Ok, answer is here: AFNetworking posts JSON arrays as multiple single-entry dictionaries
I just added a line in my ApiClient.m
_sharedClient.requestSerializer = [AFJSONRequestSerializer serializer];
I have a JSON array(dictionary?) of objects that are themselves an array. I need to find a value within one of these arrays so that I can compare it later. Part of my JSON data:
[
{
"Name": "Exhibitor",
"Url": "api/congress/exhibitor",
"ResourceType": "Data",
"LastMod": 1389106977
},
{
"Name": "Workshop",
"Url": "api/congress/workshop",
"ResourceType": "Data",
"LastMod": 1389106977
},
{
"Name": "Speaker",
"Url": "api/congress/Speaker",
"ResourceType": "Data",
"LastMod": 1389106977
},
]
My method receives a table name as a parameter and returns a time stamp. How would I receive the time stamp (1389106977) for the table "workshop" for example? This seems so simple but I cannot work it out for 'nested' arrays/dictionaries.
Thanks,
edit:
This is the my code with trojanfoe's added to it.
NSError* localError;
NSMutableArray *syncDataArray = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
if (syncDataArray)
{
NSNumber *lastMod = nil;
for (NSDictionary *dict in syncDataArray)
{
NSLog(#"current table is: %#", dict[#"Name"]);
if ([tableName isEqualToString:dict[#"Name"]])
{
lastMod = dict[#"LastMod"];
//break;
}
}
NSLog(#"LastMod = %#", lastMod);
}
else
{
NSLog(#"syncDataArray is empty");
}
This works perfectly and makes sense
The JSON data looks like an array of dictionaries, so you can iterate over the array and test for the "Name" entry:
NSArray *jsonData = ...; // You have converted JSON to Objective-C objects already
NSNumber *lastMod = nul;
for (NSDictionary *dict in jsonData) {
if ([#"Workshop" isEqualToString:dict[#"Name"]]) {
lastMod = dict[#"LastMod"];
break;
}
}
if (lastMod) {
// You found it
}
(Note I am not certain the type of object used to store the "LastMod" object, so you might need to do some debugging to find out).
EDIT If you make extensive use of this data you should immediately convert the JSON data into an array of (custom) model objects, which will make it easier to manipulate the data as your app becomes more complex.
You have an array for dictionaries so it would look something like :
NSNumber *timestamp = [[JSON objectAtIndex:index] objectForKey:#"LastMod"];
NSNumber *timestamp = response[1][#"LastMod"];
I have the following situation:
NSDictionary *params = #{
#"Checkout" : #{
#"conditions" : #{#"Checkout.user_id" : #1},
#"order" : #{#"Checkout.id" : #"DESC"}
},
#"PaymentState" : #[],
#"Offer" : #[]
};
This dictionary contains params for a webservice request passing a JSON string with the webservice URL. I get the JSON string using NSJSONSerialization class, like this:
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:params options:0 error:nil];
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
The problem is: jsonString "keys" is ordered differently from the original params dictionary keys order, like this:
{
"Offer":[],
"PaymentState":[],
"Checkout":{
"conditions":{"Checkout.user_id":6},
"order":{"Checkout.id":"DESC"}
}
}
That is, the "PaymentState" and "Offer" keys come first in jsonString, and i need maintain
the original order. This is very important, like this:
{
"Checkout":{
"conditions":{"Checkout.user_id":6},
"order":{"Checkout.id":"DESC"}
},
"Offer":[],
"PaymentState":[]
}
So guys, how can i do that??
I use OrderedDictionary from CocoaWithLove whenever I need to keep the order of my dictionary keys.
Basically, OrderedDictionary contains an NSMutableDictionary and an NSMutableArray for the keys inside it, to keep track of the order of the keys. It implements the required methods for subclassing NSDictionary/NSMutableDictionary and just "passes" the method call to the internal NSMutableDictionary.
According to the JSON spec a JSON object is specifically unordered. Every JSON library is going to take this into account. So even when you get around this issue for now, you're almost certainly going to run into issues later; because you're making an assumption that doesn't hold true (that the keys are ordered).
While NSDictionary and Dictionary do not maintain any specific order for their keys, starting on iOS 11 and macOS 10.13, JSONSerialization supports sorting the keys alphabetically (see Apple documentation) by specifying the sortedKeys option.
Example:
let data: [String: Any] = [
"hello": "world",
"a": 1,
"b": 2
]
let output = try JSONSerialization.data(withJSONObject: data, options: [.prettyPrinted, .sortedKeys])
let string = String(data: output, encoding: .utf8)
// {
// "a" : 1,
// "b" : 2,
// "hello" : "world"
// }
I've got a question regarding parsing a JSON response within iOS5.
Currently, I'm following this guide here to help me parse the JSON response returned from a third-party mapping service.
Everything works, except that the JSON response returned by the third-party server is somewhat different from the one shown in the guide itself.
In a nutshell, the overall structure of the entire JSON response looks something like this:
{
"directions": [....],
"messages": [....],
"routes":
{
"features": [
{
"attributes": {....},
"geometry":
{
"paths": [....]
}
}
]
}
}
This is the actual JSON query URL.
By using this line of code,
NSDictionary * jsonResponse = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
I am able to sucessfully get the jsonResponse dictionary to report that it has 3 key/value pairs, but my ultimate goal is to retrieve the array stored in 'routes.features.geometry.paths'.
This is my current code block that gets the final set of array values:
NSDictionary * jsonResponse = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error];
NSArray * jsonArray = [jsonResponse valueForKeyPath:#"routes.features.geometry.paths"];
jsonArray = [jsonArray objectAtIndex:0];
jsonArray = [jsonArray objectAtIndex:0];
I was wondering if anyone might have a better idea of how I should go about doing this in a more elegant fashion?
Thanks a lot in advance!
You can't just use it as JSON object because it will be working as JSON (Plain String) and you need to parse it so for your problem you can do like this to directly go to paths
NSArray *arr = [[[[jsonResponse objectForKey:#"routes"] objectForKey:#"features"] objectForKey:#"geometry"] objectForKey:#"paths"];
Now you can access your paths data from "arr" array
UPDATE:
NSArray *arr = [[[[[jsonResponse objectForKey:#"routes"] objectForKey:#"features"] objectAtIndex:0] objectForKey:#"geometry"] objectForKey:#"paths"];
as features element is an Array so traverse array first then goto its elements