I have JSON data:
{"data":[
{"userID":"1", "username":"name1"},
{"userID":"2", "username":"name2"},
{"userID":"3", "username":"name3"}
]}
returned into an NSDictionary.
NSDictionary *jsonObject = [NSJSONSerialization JSONObjectWithData:jsonReturnData options:kNilOptions error:&err];
The jsonObject looks like this:
How do I then read the values in the NSDictionary? I have:
NSDictionary *dictItem1 = (NSDictionary *)jsonObject;
which reads the data item but how do get the values?
Finally got it reading the data into an NSArray:
NSArray *JsonData = [NSJSONSerialization JSONObjectWithData:jsonReturnData options:NSJSONReadingAllowFragments error:&err];
NSArray *array = [JsonData objectAtIndex:0];
NSDictionary *dictItem = (NSDictionary *)array;
NSArray *arrayItems = [dictItem objectForKey:#"data"];
The arrayItems then held each of the records.
As pointed out it be further simplified with:
NSArray *JsonData = [NSJSONSerialization JSONObjectWithData:jsonReturnData options:NSJSONReadingAllowFragments error:&err];
NSDictionary *dictItem = (NSDictionary *)[JsonData objectAtIndex:0];;
NSArray *arrayItems = [dictItem objectForKey:#"data"];
Related
I have JSON data that looks as such:
{
"dataset": {
"id": ,
"dataset_code": "",
"database_code": "",
"name": "",
"description": "",
"refreshed_at": "",
}
}
When I go to NSLog the JSON data using the "dataset" identifier it prints fine. However I want to access the next level of JSON data which is what I'm looking to use. However, when I try to NSLog the next level I get an error in xcode. My code looks as such:
NSString *query = #"jsonwebsite.com";
NSData *jsonData = [NSData dataWithContentsOfURL:[NSURL URLWithString:query]];
_Array = [[NSMutableArray alloc] init];
_Array = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
So if I use this it's logs fine.
NSString *testString = [_Array valueForKey:#"dataset"];
NSLog(#"%#",testString);
But as mentioned, I'm looking for the next set of data and when I try this, it gives an error.
NSString *testString = [_Array valueForKey:#"name"];
NSLog(#"%#",testString);
It returns (null). How would I be able to access the name field in this JSON data?
There is a lot wrong with your code.
_Array = [[NSMutableArray alloc] init];
_Array = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
There is no point to creating an empty array in the first line, only to replace it with a different object in the second line.
Your data contains a dictionary of dictionaries, not an array. You should create a variable dictionary:
NSMutableDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
You should not use valueForKey to fetch values from your dictionary. That is a KVO method. Use objectForKey instead, or better yet, use modern dictionary syntax:
NSMutableDictionary *dataSet = dictionary[#"dataset"];
NSString *name = dataSet[#"name"];
if (name == nil) {
NSLog(#"name is nil");
}
else if (name.length == 0) {
NSLog(#"name is empty");
}
else {
NSLog(#"Name is %#", name);
}
your json is a NSDictionary not a NSMutableArray,you used a NSMutableArray to recieve a NSDictionary was wrong.
test this:
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
NSDictionary *subDict = dict[#"dataset"];
NSLog(#"%#", subDict);
NSLog(#"%#", subDict[#"name"]);
Change this code:
NSString *query = #"jsonwebsite.com";
NSData *jsonData = [NSData dataWithContentsOfURL:[NSURL URLWithString:query]];
_Array = [[NSMutableArray alloc] init];
_Array = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
NSString *testString = [_Array valueForKey:#"name"];
NSLog(#"%#",testString);
into this:
NSString *query = #"jsonwebsite.com";
NSData *jsonData = [NSData dataWithContentsOfURL:[NSURL URLWithString:query]];
_Array = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:nil];
NSDictionary *dataSet = [_Array objectForKey:#"dataset"];
NSString *testString = [dataSet objectForKey:#"name"];
NSLog(#"%#",testString);
NSURL *url = [NSURL URLWithString:#"file://localhost/Users/admin/Desktop/JSON/vivijson.json"];
NSDictionary *regDict = [[NSDictionary alloc] initWithObjectsAndKeys:self.loginString, #"login",
self.nameString, #"name",
self.lastNameString, #"lastName",
self.emailString, #"email",
self.numberString, #"number", nil];
NSError *error;
NSMutableArray *regMutArray = [[NSMutableArray alloc] init];
[regMutArray addObject:regDict];
NSData *jsonConvRegArrayData = [NSJSONSerialization dataWithJSONObject:regMutArray options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonRegString = [[NSString alloc] initWithData:jsonConvRegArrayData encoding:NSUTF8StringEncoding];
[jsonConvRegArrayData writeToURL:url atomically:YES];
This method are re-writing JSON, and start it again, but i need to add some to my JSON.
You should first read the exiting JSON into a mutable array using JSONObjectWithData using NSJSONReadingMutableContainers as the reading options. Then add the new array element to the mutable array returned by JSONObjectWithData and then convert it back to an JSON using dataWithJSONObject
Here's the code.
NSURL *url = [NSURL URLWithString:#"file://localhost/Users/Shared/vivijson.json"];
NSDictionary *regDict = [[NSDictionary alloc] initWithObjectsAndKeys:#"self.loginString, #"login",
self.nameString, #"name",
self.lastNameString, #"lastName",
self.emailString, #"email",
self.numberString, #"number", nil];
NSError *error;
NSMutableArray *regMutArray = [[NSMutableArray alloc] init];
[regMutArray addObject:regDict];
NSData *data = [NSData dataWithContentsOfURL:url];
NSMutableArray *array = nil;
if (data)
array = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];
if (array == nil)
{
array = [[NSMutableArray alloc] init];
}
[array addObjectsFromArray:regMutArray];
NSData *jsonConvRegArrayData = [NSJSONSerialization dataWithJSONObject:array options:NSJSONWritingPrettyPrinted error:&error];
NSString *jsonRegString = [[NSString alloc] initWithData:jsonConvRegArrayData encoding:NSUTF8StringEncoding];
[jsonRegString writeToURL:url atomically:true encoding:NSUTF8StringEncoding error:nil];
How do I get true/false (instead of "true"/"false") in json from a NSDictionary using NSJSONSerialization dataWithJSONObject? What keys should I store in the dictionary to get that?
NSNumber objects containing a BOOL are mapped to JSON "true" and "false".
So just use #YES, #NO, or generally #(someBOOL). For example:
NSDictionary *dict = #{#"this is": #YES};
NSData *data = [NSJSONSerialization dataWithJSONObject:dict options:0 error:NULL];
NSString *str = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
// {"this is":true}
I am getting the following response from server
[{"id":"16","name":"Bob","age":"37"},{"id":"17","name":"rob","age":"28"}];
I am using AFNetworking framework for it,
I am getting the above response in NSData and then using the the below code, I am able to collect the data in NSDictionary
NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingAllowFragments error:&error];
But how to parse the "name" and "age" value from that NSDictionary?
You expected NSDictionary but your response gives you array of dictionaries, try this:
NSArray *array = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingAllowFragments error:&error];
for (NSDictionary *dict in array)
{
NSLog(#"Name: %#, age: %#", dict[#"name"], dict[#"age"]);
}
//Extended
From the comment below it looks like you have a string from the response, not NSArray as you show in the code above.
You can parse string to get the data you want or you can convert it back to the json and NSArray:
NSString * jsonString = [NSJSONSerialization JSONObjectWithData:response options:NSJSONReadingAllowFragments error:&error];
NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSArray *array = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
//As I post above
Now you should have an NSArray and my code should do the job.
I am trying to parse some Json with Objective C.
My problem is that I am getting the correct json back but when I try parse some of the json my app crashes.
// i will use a code from connect to DB tutorial
NSString *strURL = [NSString stringWithFormat:#"http://www.ddproam.co.za/Central/Asset/AssetsWithSerial?Serial=S00000001"];
// to execute php code
NSData *dataURL = [NSData dataWithContentsOfURL:[NSURL URLWithString:strURL]];
// to receive the returend value
NSString *strResult = [[NSString alloc] initWithData:dataURL encoding:NSUTF8StringEncoding];
NSLog(#"Login response:%#",strResult);
NSError *error;
//parse out the json data
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:dataURL //1
options:kNilOptions
error:&error];
NSArray* defineJsonData = [json objectForKey:#"AssetDesc"]; //2
NSLog(#"value: %#", defineJsonData); //3
Here is my json:
[{"AssetID":1,"AssetName":"Asset 1","AssetDesc":"This is a manually inserted Asset","AssetTypeID":1,"AssetTypeDesc":"This is a manually inserted Asset Type"}]
I am trying to get the AssestName out of the string. I must be doing something wrong.
The whole thing is an array containing a dictionary, not a dictionary containing an array...
This is a very dirty way to get the value you want - you want to write something more safe than this. Try checking the type of class returned before you try to use it...
NSArray* json = [NSJSONSerialization JSONObjectWithData:dataURL //1
options:kNilOptions
error:&error];
NSDictionary* defineJsonData = [json lastObject]; //2
NSLog(#"value: %#", [defineJsonData objectForKey:#"AssetDesc"]); //3