I get this JSON object from my web service
0: {
Username: "John"
Password: "12345"
Position: "Admin"
Job: "Developer"
ResourceJobId: 1
}
When I try to assign a value, for example, to Username JSON string, I get a semantic error:
id obj = [NSJSONSerialization JSONObjectWithData:data
options:NSJSONReadingAllowFragments
error:&error];
for (NSDictionary *dictionary in array) {
NSString *usernameString = #"";
//this line of code gives me an error: Expression is not assignable
[dictionary objectForKey:#"Username"] = usernameString ;
I know how get the JSON object with NSJSONSerialization class, but my target is how assign the value #"" to the JSON object.
So how can I assign the value #"" to the Username JSON string?
While you are trying to fetched dictionary from array. it is not mutable dictionary so you need to created NSMutableDictionary while fetching data from Array. following code will help you to change username.
for (NSMutableDictionary *dictionary in array)
{
NSMutableDictionary* dictTemp = [NSMutableDictionary dictionaryWithDictionary:dictionary];
[dictTemp setObject:usernameString forKey#"Username"];
[_arrayList replaceObjectAtIndex:index withObject:dictTemp];
}
Well your assignment operation is written wrong, it should be indeed like this:
If you need to get value from dictionary
usernameString = [dictionary objectForKey:#"Username"];
If you want to set a value to your dictionary, first of all your dictionary should be NSMutableDictionary
[dictionary setObject:usernameString forKey:#"Username"];
NSData *data = [NSData dataWithContentsOfURL:url];
NSError *error;
id obj = [NSJSONSerialization JSONObjectWithData:data
options:NSJSONReadingAllowFragments
error:&error];
if(!error && [obj isKindOfClass:[NSArray class]]){
NSArray *array = (NSArray *)obj;
Booking *booking = nil;
for (NSMutableDictionary *dictionary in array) {
NSString *usernameString = #"";
//this line of code gives me an error: Expression is not assignable
[dictionary objectForKey:#"Username"] = usernameString;
Yes, is a compiler error
You need to have a mutabledictionary inorder to change the value. Try this
for (NSDictionary *dictionary in array) {
NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionary];
NSString *usernameString = #"";
[mutableDictionary setValue:#"" forKey:usernameString];
}
Even the answers are correct, I want to add that you do not have to do this your own. NSJSONSerialization already has a solution for that. Simply pass as options one of these:
NSJSONReadingMutableContainers = (1UL << 0),
NSJSONReadingMutableLeaves = (1UL << 1),
when reading the JSON.
Related
Can anybody help me create an NSDictionary format of the following structure:
{
key1 = "value1";
key2 = "value2";
key3 = [
{
key01 = "value01";
key02 = "value02";
},
{
key01 = "value01";
key02 = "value02";
},
{
key01 = "value01";
key02 = "value02";
}
];
}
Try this code it might help you.
NSDictionary *dicationary = #{
#"key1":#"value1",
#"key2":#"value2",
#"key3":#[#{#"key01":#"value01",#"key02":#"value02"},
#{#"key01":#"value01",#"key02":#"value02"},
#{#"key01":#"value01",#"key02":#"value02"}]
};
There is API in obj-c to convert Json to nsdictionary .I guess you should try that :
First convert json to nsdata (assuming you above JSON is in string format)
2.Then you API to convert that to NSDictionary :
NSDictionary *dictionary = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
Just to answer your question about converting that JSON data to NSDictionary, here it is:
(assuming you already got your JSON data)
// add the first 2 VALUES with it's KEYS
NSMutableDictionary *mainDict = [NSMutableDictionary dictionary];
[mainDict setValue:VALUE1 forKey:KEY1];
[mainDict setValue:VALUE2 forKey:KEY2];
// then for the last KEY, create a mutable array where you will store your sub dictionaries
NSMutableArray *ma = [NSMutableArray array];
NSMutableDictionary *subDict = [NSMutableDictionary dictionary];
[subDict setValue:SUB_VALUE1 forKey:SUB_KEY1];
[subDict setValue:SUB_VALUE1 forKey:SUB_KEY2];
[ma addObject:subDict];
// then add that array to your main dictionary
[mainDict setValue:ma forKey:KEY3];
// check the output
NSLog(#"mainDict : %#", mainDict);
// SAMPLE DATA - Test this if this is what you want
NSMutableDictionary *mainDict = [NSMutableDictionary dictionary];
[mainDict setValue:#"value1" forKey:#"key1"];
[mainDict setValue:#"value2" forKey:#"key2"];
NSMutableArray *ma = [NSMutableArray array];
NSMutableDictionary *subDict = [NSMutableDictionary dictionary];
[subDict setValue:#"subValue1" forKey:#"subKey1"];
[subDict setValue:#"subValue2" forKey:#"subKey2"];
[ma addObject:subDict];
[mainDict setValue:ma forKey:#"key3"];
NSLog(#"mainDict : %#", mainDict);
The following should work for you:
NSString *jsonString = #"{\"ID\":{\"Content\":268,\"type\":\"text\"}}";
NSData *data = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *jsonDict = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
NSLog(#"%#", jsonDict[#"ID"][#"Content"]);
Will return you:
268
I get this JSON from a web service:
{
"Respons": [{
"status": "101",
"uid": "0"
}]
}
I have tried to access the data with the following:
NSError* error;
//Response is a NSArray declared in header file.
self.response = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];
NSString *test = [[self.response objectAtIndex:0] objectForKey:#"status"]; //[__NSCFDictionary objectAtIndex:]: unrecognized selector sent to instance
NSString *test = [[self.response objectForKey:#"status"] objectAtIndex:0]; //(null)
But none of them work, if i NSLog the NSArray holding the serialized data, this i what i get:
{
Respons = (
{
status = 105;
uid = 0;
}
);
}
How do i access the data?
Your JSON represents a dictionary, for whom the value associated with the Respons key is an array. And that array has a single object, itself a dictionary. And that dictionary has two keys, status and uid.
So, for example, if you wanted to extract the status, I believe you need:
NSArray *array = [self.response objectForKey:#"Respons"];
NSDictionary *dictionary = [array objectAtIndex:0];
NSString *status = [dictionary objectForKey:#"status"];
Or, in latest versions of the compiler:
NSArray *array = self.response[#"Respons"];
NSDictionary *dictionary = array[0];
NSString *status = dictionary[#"status"];
Or, more concisely:
NSString *status = self.response[#"Respons"][0][#"status"];
Your top level object isn't an array, it's a dictionary. You can easily bypass this and add the contents of that key to your array.
self.response = [[NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error] objectForKey:#"Respons"];
When check self.weatherData, I get nothing even though there is data in "data". Here is my function:
- (void)handleNetworkResponse:(NSData *)myData
{
//NSMutableDictionary *data = [NSMutableDictionary dictionary];
NSMutableDictionary *data = [[NSMutableDictionary alloc] init];
// now we'll parse our data using NSJSONSerialization
id myJSON = [NSJSONSerialization JSONObjectWithData:myData options:NSJSONReadingMutableContainers error:nil];
// typecast an array and list its contents
NSDictionary *jsonArray = (NSDictionary *)myJSON;
// take a look at all elements in the array
for (id element in jsonArray) {
id key = [element description];
id innerArr = [jsonArray objectForKey:key];
NSDictionary *inner = (NSDictionary *)innerArr;
if ([inner conformsToProtocol:#protocol(NSFastEnumeration)]) {
for(id ele in inner) {
id innerKey = [ele description];
[data setObject:[[inner valueForKey:innerKey] description] forKey:[ele description]];
}
}
else {
[data setObject:[inner description] forKey:[element description]];
}
}
NSLog([data description]);
self.weatherData = data;
}
However when check self.weatherData, I get nothing even though there is data in "data".
Issue was data isn't there when I assign it to the variable from the an asynchronous method :D
all fixed now by adding a delegate call back
I have some code that looks like this:
NSDictionary* json = [NSJSONSerialization JSONObjectWithData:data
options:kNilOptions
error:&error];
NSArray *arrRequests = [NSJSONSerialization JSONObjectWithData:data
options:NSJSONReadingMutableContainers
error:nil];
// Loop through the array and generate the necessary annotation views
for (int i = 0; i<= arrRequests.count - 1; i++)
{
//now let's dig out each and every json object
NSDictionary *dict = [arrRequests objectAtIndex:i];
NSString *is_private = [NSString
stringWithString:[dict objectForKey:#"is_private"]];
...
It works when the value for is_private is 1 or 0, but if it is null it crashes with an exception on this line:
NSString *is_private = [NSString stringWithString:[dict objectForKey:#"is_private"]];
Is there a way to check if it is not null or handle this so that it is able to put nil into the NSString *is_private variable?
Thanks!
You should be able to handle it like so:
id value = [dict valueForKey:#"is_private"];
NSString *is_private = [value isEqual:[NSNull null]] ? nil : value;
Your problem has nothing to do with NSJSONSerialization and everything to do with the fact that you're passing a nil value to stringWithString:. Why not just simply that line to NSString *is_private = [dict objectForKey:#"is_private"];?
Also, why are you using an NSString to store a boolean value? An NSNumber would be much better-suited.
Why don't you just check if [dict objectForKey:#"is_private"] is nil or [NSNull null] before passing it to stringWithString:?
I created a web service which returns JSON or so I think. The data returned look like this:
{"invoice":{"id":44,"number":42,"amount":1139.99,"checkoutStarted":true,"checkoutCompleted":true}}
To me, that looks like valid JSON.
Using native JSON serializer in iOS5, I take the data and capture it as a NSDictionary.
NSError *error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:[request responseData] options:kNilOptions error:&error];
NSLog(#"json count: %i, key: %#, value: %#", [json count], [json allKeys], [json allValues]);
The output of the log is:
json count: 1, key: (
invoice
), value: (
{
amount = "1139.99";
checkoutCompleted = 1;
checkoutStarted = 1;
id = 44;
number = 42;
}
)
So, it looks to me that the JSON data has a NSString key "invoice" and its value is NSArray ({amount = ..., check...})
So, I convert the values to NSArray:
NSArray *latestInvoice = [json objectForKey:#"invoice"];
But, when stepping through, it says that latestInvoice is not a CFArray. if I print out the values inside the array:
for (id data in latestInvoice) {
NSLog(#"data is %#", data);
}
The result is:
data is id
data is checkoutStarted
data is ..
I don't understand why it only return the "id" instead of "id = 44". If I set the JSON data to NSDictionary, I know the key is NSString but what is the value? Is it NSArray or something else?
This is the tutorial that I read:
http://www.raywenderlich.com/5492/working-with-json-in-ios-5
Edit: From the answer, it seems like the "value" of the NSDictionary *json is another NSDictionary. I assume it was NSArray or NSString which is wrong. In other words, [K,V] for NSDictionary *json = [#"invoice", NSDictionary]
The problem is this:
NSArray *latestInvoice = [json objectForKey:#"invoice"];
In actual fact, it should be:
NSDictionary *latestInvoice = [json objectForKey:#"invoice"];
...because what you have is a dictionary, not an array.
Wow, native JSON parser, didn't even notice it was introduced.
NSArray *latestInvoice = [json objectForKey:#"invoice"];
This is actually a NSDictionary, not a NSArray. Arrays wont have keys. You seem capable from here.
Here I think You have to take to nsdictionary like this
NSData* data = [NSData dataWithContentsOfURL: jsonURL];
NSDictionary *office = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSDictionary *invoice = [office objectForKey:#"invoice"];