In my application I am using a JsonModel for parsing JSON response from server and while storing it in Core Data I am using NSManagedObject and NSManagedContext which is provided by Apple itself. Now whenever I fetch I want to convert the NSManagedObject to JsonModel. Now the problem is I have to use two separate class to manage jsonModel and NSManagedObject.
You can get help from this link.
Get Core Data objects to JSON
Or in easy way from andrew-madsen's Answer
NSManagedObject *managedObject = ...;
NSArray *keys = [NSArray arrayWithObjects:#"key1", #"key2", ..., nil]; // These are the keys for the properties of your managed object that you want in the JSON
NSString *json = [[managedObject dictionaryWithValuesForKeys:keys] JSONRepresentation];
For more detail try this link
nsmanagedobject-to-json
Hope it helps you. first try to convert your NSMangedObject to NSDictionary.
NSArray *keys = [[[yourObject entity] attributesByName] allKeys];
NSDictionary *dict = [myObject dictionaryWithValuesForKeys:keys];
the you have to use dict as a JSON or convert them into JSON string if needed.
Related
I'm new to iOS and looking for a little help. I am connecting to my socket server but having trouble emitting.
Heres how to emit:
if (self.socketIsConnected)
{
[self.socket emit:(NSString HERE) args:#[(NSArray HERE)]];
}
Heres what I tried:
if (self.socketIsConnected)
{
NSDictionary *deviceDic = #{#"username": #"drew", #"chatHash":#"FJHE8"};
[self.socket emit:#"adduser" args:#[[NSString stringWithFormat: #"%#", deviceDic]]];
}
The "args" param asks for a NSArray, but I need to send a JSON object that looks like this:
{"username": "drew", "chatHash":"FJHE8"}
How can I create this? And how do I put this object in the NSArray.
Update:
I tried this now
NSArray *keys = [NSArray arrayWithObjects:#"username", #"chatHash", nil];
NSArray *objects = [NSArray arrayWithObjects:#"drew", #"value2", nil];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:objects
forKeys:keys];
[self.socket emit:#"adduser" args:dictionary];
and I looked on the server. It crashes my server with a throw exception. and the only data it receives is:
username
It appears that you're using SIOSocket. The documentation isn't very clear but looking at the source for the emit function (https://github.com/MegaBits/SIOSocket/blob/master/SocketIO/Source/SIOSocket.m), all you need to do is pass an NSArray with the first parameter being an NSDictionary. The dictionary will be serialized as a JSON object by the framework.
You can have multiple arguments in the emit call. The type of each parameter in argument depends on the types of objects in the array you pass. If you pass a dictionary, it'll convert it to a JSON object, an array to an array, numbers as numbers, strings as strings.
You can use
NSDictionary *subArgs = #{#"state" : #true};
[self.socket emit:#"adduser" args:#[subArgs]];
This will solve the problem.
I am putting two NSMutableArray objects into an NSDictionary and trying to serialize, but the method call is returning nil. One array, addresses, is an array of NSString objects. The other, engines is an array of objects that each contain several data types. I am attempting to serialize using the following code:
NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] init];
[dictionary setObject:engAddr forKey:#"engAddr"];
[dictionary setObject:trainList forKey:#"engines"];
NSData *data = [NSPropertyListSerialization dataFromPropertyList:dictionary
format:NSPropertyListXMLFormat_v1_0
errorDescription:&error];
Stepping through, the debugger shows the arrays are properly added to the dictionary, but after the line that should serialize the dictionary it shows data = (NSData *) nil.
Where am I going wrong? Thank you for your help!
What kind of objects does engines contain?
Plist supports only specific objects below.
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/PropertyLists/AboutPropertyLists/AboutPropertyLists.html#//apple_ref/doc/uid/10000048i-CH3-54303
If you want to serialize a custom object, convert it to NSData by NSKeyedArchiver.
To do that, objects must conform NSCoding protocol.
i'm trying to achieve the following structure:
NSMutableDictionary *dict = [#{} mutableCopy];
NSDictionary *key1 = #{#"id_format": #(1), #"date": #"2014-08-01"};
NSDictionary *key2 = #{#"id_format": #(2), #"date": #"2014-08-02"};
// This runs perfect and can be checked in llvm debugger
// data1 & data2 are NSArray that contain several NSDictionary
[dict setObject:data1 forKey:key1];
[dict setObject:data2 forKey:key2];
// Later, if i try to access dict using another key, returns empty NSArray
NSDictionary *testKey = #{#"id_format": #(1), #"date": #"2014-08-01"}; // Note it's equal to "key1"
for(NSDictionary *dictData in dict[testKey]){
// dictData is empty NSArray
}
// OR
for(NSDictionary *dictData in [dict objectForKey:testKey]){
// dictData is empty NSArray
}
So the question is if is there possible to use NSDictionary as key, or not.
An object can be used as a key if it conforms to NSCopying, and should implement hash and isEqual: to compare by value rather than by identity.
Dictionaries follow the array convention of returning [self count] for hash. So it's a pretty bad hash but it's technically valid. It means your outer dictionary will end up doing what is effectively a linear search but it'll work.
Dictionaries implement and correctly respond to isEqual:. They also implement NSCopying.
Therefore you can use a dictionary as a dictionary key.
I have an array structure as follows:
NSMutableArray topArray{
NSMutableArray middleArray{
NSMutableArray lowerArray{
NSMutableDictionary dict{
}
}
}
}
The array structure is filled with some data that I retrieve from the web is JSON format.
I am trying to edit one of the objects in the NSMutableDictionary as follow:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
NSMutableArray *lowerArray = [[self middleArray] objectAtIndex:[indexPath section]];
NSMutableDictionary *dict = [lowerArray objectAtIndex:[indexPath row]];
[dict setObject:[NSNumber numberWithInt:1] forKey:#"key"];
[[self tableView] reloadData];
}
The data within each of the arrays is correct (I have checked with print statements), however, when I try to change the object in the dict I get the following error:
reason:
'-[__NSCFDictionary setObject:forKey:]: mutating method sent to
immutable object'
I need the object in the dictionary to be changed within the array structure.
Could this be an issue with the JSON data since when topArray is first initialised with the JSON data the middle and lower arrays are in the form of just NSArray's?
Sorry if this is confusing, I will try to clarify more if you have any questions.
Thanks in advance for your help.
If you're using NSJSONSerialization, you can pass NSJSONReadingMutableContainers to the options parameter of +JSONObjectWithData:options:error:, and all of the parsed dictionaries and arrays will be mutable.
NSMutableArray *topArray = [NSJSONSerialization JSONObjectWithData:webServiceData
options:NSJSONReadingMutableContainers
error:nil];
Just use NSMutableDictionary class instead of just NSDictionary for the moduleDict variable. It is easily done when parsing JSON objects. If no - create one like this:
NSMutableDictionary *newDict = [NSMutableDictionary dictionaryWithDictionary: moduleDict];
I doubt that you are really dealing with NSMutableDictionary on the lowest level. Do you have the output from these print statements for us?
Usually the structures generated by JSON deserialisation are of immutable type. And that is exactly what your error message is telling.
I would like some help sorting an NSArray of NSDictionary values based on each objects ISV key.
This is the code I have so far for creating my array objects so you have a better idea of what I am trying to do.
NSArray *combinedKeysArray = [NSArray arrayWithObjects:#"HASM", #"ISL", #"ISV", nil];
valuesCombinedMutableArray = [NSMutableArray arrayWithObjects:[dict objectForKey:#"HASM"],
[dict objectForKey:#"ISL"],
[dict objectForKey:#"ISV"],
nil];
combinedDictionary = [NSDictionary dictionaryWithObjects:valuesCombinedMutableArray
forKeys:combinedKeysArray];
[unSortedrray addObject:combinedDictionary];
// how do I then sort unSortedArray by the string values in each object ISV key?
any help would be greatly appreciated.
This can solve your problem
How to sort an NSMutableArray with custom objects in it?
https://stackoverflow.com/a/805589/1294448
You can use NSSortDescriptor to sort NSArays
Then in NSArray you have a method called sortedArrayUsingDescriptors
Or NSComparisonResult ca also be helpful some time http://developer.apple.com/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSMutableArray_Class/Reference/Reference.html#//apple_ref/doc/uid/20000138-BABCEEJD
you won't be able to sort unSortedArray because it will only have one element in it (ie in your last line of code you are adding a single object by addObject).
That said, you cannot sort the dictionary either.. b/c dictionaries are unsorted by definition.
you can iterate over the keys of the dictionary in a specific order though, you can sort an array containing the keys of the dictionary.
NSArray *keys = [theDictionary allKeys];
NSArray *sortedKeys = [keys sortedArrayUsingSelector:#selector(compareMethod:)];
You can use -sortedArrayUsingComparator: to sort any way you need.
[unSortedrray sortedArrayUsingComparator:^NSComparisonResult(NSDictionary *dict1, NSDictionary *dict2) {
return [[dict1 objectForKey:#"ISV"] localizedCompare:[dict2 objectForKey:#"ISV"]];
}];