Save array of objects on the disc with JSONModel (IOS) - ios

Question

I read a lot of docs about this but I can't really understand how it precisely works.
I would like to save my apps data in JSON format on the disc of the phone.
I have a array of objects of this type:
#interface ObjectA : NSObject
#property (strong, nonatomic) NSMutableArray* names1;
#property (strong, nonatomic) NSMutableArray* names2;
#property (strong, nonatomic) NSMutableArray* names3;
#property (strong, nonatomic) NSMutableArray* names4;
#property (strong, nonatomic) NSString* nameObjectA;
#property (assign) int number;
By using JSONModel, how can I transforme a "NSMutableArray *ObjectA" in a JSON file and after that read this file back in the app.
Thanks.
- (id)initWithJSONDictionary:(NSDictionary *)jsonDictionary {
if(self = [self init]) {
// Assign all properties with keyed values from the dictionary
_nameObjectA = [jsonDictionary objectForKey:#"nameAction"];
_number = [[jsonDictionary objectForKey:#"number"]intValue];
_actions1 = [jsonDictionary objectForKey:#"Action1"];
_actions2 = [jsonDictionary objectForKey:#"Action2"];
_actions3 = [jsonDictionary objectForKey:#"Action3"];
_actions4 = [jsonDictionary objectForKey:#"Action4"];
}
return self;
}
- (NSArray *)locationsFromJSONFile:(NSURL *)url {
// Create a NSURLRequest with the given URL
NSURLRequest *request = [NSURLRequest requestWithURL:url
cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData
timeoutInterval:30.0];
// Get the data
NSURLResponse *response;
NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:nil];
// Now create a NSDictionary from the JSON data
NSDictionary *jsonDictionary = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
// Create a new array to hold the locations
NSMutableArray *actions = [[NSMutableArray alloc] init];
// Get an array of dictionaries with the key "actions"
NSArray *array = [jsonDictionary objectForKey:#"actions"];
// Iterate through the array of dictionaries
for(NSDictionary *dict in array) {
// Create a new Location object for each one and initialise it with information in the dictionary
Action *action = [[Action alloc] initWithJSONDictionary:dict];
// Add the Location object to the array
[actions addObject:action];
}
// Return the array of actions objects
return actions;
}

Answer 1

The demo app that comes with JSONModel includes an example how to store your app's data via a JSONMOdel: https://github.com/icanzilb/JSONModel
Check the code in this view controller: https://github.com/icanzilb/JSONModel/blob/master/JSONModelDemo_iOS/StorageViewController.m
The logic is that you can export your model to a json string or json compliant dictionary and then save those to the disc using the standard APIs. Check the code

Answer 2

In ObjectA you define two methods -- toDictionary and initWithDictionary. Roughly:
-(NSDictionary*) toDictionary {
return #{#"names1":names1, #"names2":names2, #"names3":names3, #"names4":names4, #"nameObjectA":nameObjectA, #"number":#(number)};
}
- (id) initWithDictionary:(NSDictionary*) json {
self = [super init];
if (self) {
self.names1 = json[#"names1];
... etc
self.nameObjectA = json[#"nameObjectA"];
self.number = json[#"number"].intValue;
}
return self;
}
Run the dictionary created by toDictionary through NSJSONSerialization to produce an NSData and write that to a file. To read, fetch the NSData from the file, run back through NSJSONSerialization, and use initWithDictionary.
Of course, this assumes that the contents of your dictionaries are "JSON legal" -- strings, numbers, NSArrays, or other NSDictionarys.
And, if the arrays/dictionaries being initialized are mutable, one should specify the "MutableContainers" option on NSJSONSerialization.