NSManagedObject shared properties - ios

I have just set up a simple Core Data database, and I have created a few entities with some properties. However some entities have some properties in common, like the Date parameter. Until now I do something like:
NSManagedObject * passedObject...
if ([_passedObject.entity.name isEqual:#"Archive"]){
Archive* fileObject = (Archive *)_passedObject;
myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:fileObject.fileData];
}else{
AllFiles* fileObject = (AllFiles *)_passedObject;
myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:fileObject.fileData];
}
fileData is common to both, so I would like just to be doing passedObject.fileData instead of casting the types. Can this be done?

define a protocol...
#protocol FileDataProvider
#property (strong,nonatomic) NSData* fileData;
//or -(NSData *)fileData; would be suitable for RO access
#end
and make your objects conform to that protocol
#interface Archive:NSManagedObject< FileDataProvider >
#property (strong,nonatomic) NSData* fileData;
#end
#interface AllFiles:NSManagedObject< FileDataProvider >
#property (strong,nonatomic) NSData* fileData;
#end
thus you can cast like so
myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:((id<FileDataProvider>)passedObject).fileData];
or safer
if([passedObject conformsToProtocol:#protocol(FileDataProvider)]) {
myDictionary = (NSDictionary*) [NSKeyedUnarchiver unarchiveObjectWithData:((id<FileDataProvider>)passedObject).fileData];
}

Related

Unable to store a NSMutableArray(each instance of array contains a custom object) in NSUserDefaults

It's a custom class:
#import <Foundation/Foundation.h>
#interface timeTable : NSObject
#property (nonatomic) int ID;
#property (nonatomic) NSString * type;
#property (nonatomic) NSString * time;
#property (nonatomic) NSString * busno;
#property (nonatomic) NSString * stops;
// nothing is done in it's .m file not even synthesise
// thats an other class
#import <Foundation/Foundation.h>
#import "timeTable.h"
#interface refreshDatabase : NSObject
#property (strong, nonatomic) NSMutableArray * arrayTimeTable;
#property (strong, nonatomic) timeTable * objectTimeTable;
// in it's .m file i am downloading a JSON formatted array using a
service then i am saving it to NsMutbaleArray
// downloading a json array which contains a rows of data
NSError * error;
NSArray * jsonArray = [NSJSONSerialization JSONObjectWithData:
[safeString dataUsingEncoding:NSUTF8StringEncoding]
options:NSJSONReadingAllowFragments error:&error];
NSLog(#"json Array %#", jsonArray);
// for getting an instance of array
NSDictionary * jsonElement;
for (int i=0; i<jsonArray.count ; i++)
{ // each row will be saved in an object of timetable class then that
// object will be saved to nsmutablearray
jsonElement = [jsonArray objectAtIndex:i];
objectTimeTable = [[timeTable alloc]init];
objectTimeTable.ID = [[jsonElement objectForKey:#"id"]intValue];
objectTimeTable.type = [jsonElement objectForKey:#"type"];
objectTimeTable.time = [jsonElement objectForKey:#"time"];
objectTimeTable.busno = [jsonElement objectForKey:#"busno"];
objectTimeTable.stops = [jsonElement objectForKey:#"stops"];
// adding an instance from JSON Array to our NSmutablearray
[arrayTimeTable addObject:objectTimeTable];
}//end of json Array FOR loop
// our array containnig all the objects will be saved using
//NSUserDefualts
// userDefaults is an object of NSUserDefaults
if(userDefaults)
{ // its not saving it to userdefaults
[userDefaults setObject:arrayToStore forKey:#"ArrayOfTimeTables"];
[userDefaults synchronize];
}
// retrieving the saved array from NSUSerDefaults and printing it
// using slog
timeTable *objPrint = [[timeTable alloc]init];
NSMutableArray *arrayLoader = [userDefaults arrayForKey:#"ArrayOfTimeTables"];
for (int i=0; i<arrayLoader.count ; i++)
{
objPrint = [arrayLoader objectAtIndex:i];
NSLog(#"outSide Printing For LOOP After Loading of tim # %d times havind id =%d type = %# time = %# busno = %# stops = %#",i,objPrint.ID,objPrint.type,objPrint.time,objPrint.busno,objPrint.stops);
}
Thanx a lot in helping me in advance.
Please tell me how to save that array which contains object of timetable class into nsUseDefaults and then how to load it back.
Please help me. I read a lot of similar question and answers, but don't know how to make them work for me.
Use NScoding to encode each of your custom object then add that custom object into an array then encode other and then add it to the array then save that array into NSUserDefaults
encoding and decoding of upper given question
is
the custom class .h file
#import <Foundation/Foundation.h>
#interface timeTable : NSObject<NSCoding>
#property (nonatomic) NSString * ID;
#property (nonatomic) NSString * type;
#property (nonatomic) NSString * time;
#property (nonatomic) NSString * busno;
#property (nonatomic) NSString * stops;
the custom class .m file
#import "timeTable.h"
#implementation timeTable
#synthesize ID;
#synthesize type;
#synthesize time;
#synthesize busno;
#synthesize stops;
-(void)encodeWithCoder:(NSCoder *)aCoder
{
[aCoder encodeObject:self.ID forKey:#"ID"];
[aCoder encodeObject:self.type forKey:#"type"];
[aCoder encodeObject:self.time forKey:#"time"];
[aCoder encodeObject:self.busno forKey:#"busno"];
[aCoder encodeObject:self.stops forKey:#"stops"];
}
-(id)initWithCoder:(NSCoder *)aDecoder
{
if((self = [super init])) {
//decode properties, other class vars
self.ID = [aDecoder decodeObjectForKey:#"ID"];
self.type = [aDecoder decodeObjectForKey:#"type"];
self.time = [aDecoder decodeObjectForKey:#"time"];
self.busno = [aDecoder decodeObjectForKey:#"busno"];
self.stops = [aDecoder decodeObjectForKey:#"stops"];
}
return self;
}
#end
where you encode each custom object one by one and adding it to the array then save that NSMutableArray or NSArray
into NSUserDefaults
encoding a custom object then adding it to array and saving it into user defaults
// encoding a custom object before saving it to array
NSData *encodeTimeTableObj = [NSKeyedArchiver
archivedDataWithRootObject:objectTimeTable];
addObject:encodeTimeTableObj];
//saving it to user Defaults
if(userDefaults)
{
[userDefaults setObject:arrayTimeTable
forKey:#"ArrayOfTimeTables"];
[userDefaults synchronize];
NSLog(#"saving to usedefaults");
}
retriving an array either mutable or non mutable then decoding each of its object
NSMutableArray *arrayLoader = [userDefaults
objectForKey:#"ArrayOfTimeTables"];
NSData * decode = [arrayLoader objectAtIndex:0];
  // in case of upper given custom class Time Table
timeTable *objPrint = [NSKeyedUnarchiver unarchiveObjectWithData:decode];
Use NSArray to get array from NSUSerDefaults as NSUSerDefaults return immuttable array.
If you need NSMutableArray, then convert this NSArray to NSMutableArray.
// retrieving the saved array from NSUSerDefaults and printing it
// using slog
timeTable *objPrint = [[timeTable alloc]init];
NSArray *arrayLoader = [userDefaults arrayForKey:#"ArrayOfTimeTables"];
for (int i=0; i

How to convert NSObject model class to a sub-class of NSManagedObject?

I have this simple model class that represent rss article called RSSEntry.
Now I want to start working wit core data with this model class, but I didn't create the project with the 'use core data' checkbox checked.
this is the class:
#import <Foundation/Foundation.h>
#interface FRSSEntry : NSObject{
NSString *_blogTitle;
NSString *_articleTitle;
NSString *_articleUrl;
NSDate *_articleDate;
NSString *_articleImageUrl;
NSString *_content;
}
#property (copy) NSString *blogTitle;
#property (copy) NSString *articleTitle;
#property (copy) NSString *articleUrl;
#property (copy) NSDate *articleDate;
#property (copy) NSString *articleImageUrl;
#property (copy) NSString *content;
- (id)initWithBlogTitle:(NSString*)blogTitle articleTitle:(NSString*)articleTitle articleUrl:(NSString*)articleUrl articleDate:(NSDate*)articleDate articleImageUrl:(NSString *)imageUrl andContent:(NSString *)content;
#end
the implementations is:
#import "FRSSEntry.h"
#implementation FRSSEntry
#synthesize blogTitle = _blogTitle;
#synthesize articleTitle = _articleTitle;
#synthesize articleUrl = _articleUrl;
#synthesize articleDate = _articleDate;
#synthesize articleImageUrl = _articleImageUrl;
#synthesize content = _content;
- (id)initWithBlogTitle:(NSString*)blogTitle articleTitle:(NSString*)articleTitle articleUrl:(NSString*)articleUrl articleDate:(NSDate*)articleDate articleImageUrl:(NSString *)imageUrl andContent:(NSString *)content
{
if ((self = [super init])) {
_blogTitle = [blogTitle copy];
_articleTitle = [articleTitle copy];
_articleUrl = [articleUrl copy];
_articleDate = [articleDate copy];
_articleImageUrl = [imageUrl copy];
_content = [content copy];
}
return self;
}
#end
very simple. Now how do I convert it so I can use it as a core data entity?
So to transform your model class into an NSManagedObject subclass you have to remove the instance variable declarations. Then replace all your #synthesize statements with #dynamic. This tells the compiler that CoreData will provide the implementation for those properties so it can do it's magic there. The custom initializer you have then also needs to be removed because NSManagedObject objects are initialized in a different way.
The code would look something like
#import <Foundation/Foundation.h>
#interface FRSSEntry : NSManagedObject
#property (copy) NSString *blogTitle;
#property (copy) NSString *articleTitle;
#property (copy) NSString *articleUrl;
#property (copy) NSDate *articleDate;
#property (copy) NSString *articleImageUrl;
#property (copy) NSString *content;
#end
-
#import "FRSSEntry.h"
#implementation FRSSEntry
#dynamic blogTitle;
#dynamic articleTitle;
#dynamic articleUrl;
#dynamic articleDate;
#dynamic articleImageUrl;
#dynamic content;
#end
You usually initialize them with something like
// Get the entity description
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"FRSSEntry" inManagedObjectContext:context];
// Insert a new YourModelObject into the context
ReceivedMessage *newMessage = [[FRSSEntry alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:context];
You could have a custom initializer but you would have to call [super initWithEntity:entityDescription insertIntoManagedObjectContext:context]. The initializer would get really long with all this parameters so I suggest you just set each property once you have the object initialized.
Judging from your response, you have just begun CoreData integration. Creating an NSManagedObject subclass is just a tip of the iceberg when working with core data. CoreData is a big an complex framework so I suggest you start by reading https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/CoreData/cdProgrammingGuide.html. Stack Overflow is also full of questions and great answers on this topic.
Another thing I suggest you look into is MagicalRecord. It's a great library that makes some of the tedious tasks very simple: https://github.com/magicalpanda/MagicalRecord

MOTIS Object Mapping, With NSDictionary with values NSArray how can I specify type of array elements?

I have the json
{"Types":{
"food":[{"cve":"1","description":"Pizza"},{"cve":"2","description":"Restaurant"},{"cve":"3","description":"Cafe"}],
"Health":[{"cve":"3","description":"Pharmacy"},{"cve":"4","description":"Hospital"}]
} }
Types.h
#import <Foundation/Foundation.h>
#interface Types: NSObject
#property (nonatomic, copy) NSDictionary *types;
#end
Types.m
#import "Types.h"
#import <Motis/Motis.h>
#import "SubTipo.h"
#implementation Types
+ (NSDictionary*)mts_mapping
{
return #{#"types": mts_key(types),};
}
#end
Subtype.h
#import <Foundation/Foundation.h>
#interface Subtype: NSObject
#property (nonatomic, assign) int cve;
#property (nonatomic, copy) NSString *description;
#end
Subtype.m
#import "Subtype.h"
#import <Motis/Motis.h>
#implementation Subtype
+ (NSDictionary*)mts_mapping
{
return #{#"cve": mts_key(cve),
#"description": mts_key(description),
};
}
#end
I deserialize with
Types * values=[[Types alloc]init];
NSDictionary * jsonObject = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
[values mts_setValuesForKeysWithDictionary:jsonObject ];
I get NSDictionary with NSArray of NSDictionary
but I need NSDictionary with NSArray of Subtypes
I try with
+ (NSDictionary*)mts_arrayClassMapping
{
return #{mts_key(types): Subtype.class};
}
but wasn't successful
How can I get these with Motis
As far as I see, your Types object is not properly defined. If you have an attribute of type NSDictionary* and the JSON received is a Dictionary, Motis won't perform any automatic conversion as the types already match (you are receiving a dictionary and your attribute is of type NSDictionary).
Therefore, you must implement your Type object following your JSON structure. This means that your Type object must have two properties of type array, one for food and one for health. Then, using the method +mts_arrayClassMapping you can specify the content type of the arrays to Subtype.
Here the implementation:
// ***** Type.h file ***** //
#interface Type: NSObject
#property (nonatomic, strong) NSArray *food;
#property (nonatomic, strong) NSArray *health;
#end
// ***** Type.m file ***** //
#implementation Type
+ (NSDictionary*)mts_mapping
{
return #{#"food": mts_key(food),
#"Health": mts_key(health),
};
}
+ (NSDictionary*)mts_arrayClassMapping
{
return #{mts_key(food): Subtype.class,
mts_key(health): Subtype.class,
};
}
#end
Regarding the implementation of Subtype, yours is already correct. However, you should not use the property name description as it is already being used by NSObject:
// ***** Subtype.h file ***** //
#interface Subtype: NSObject
#property (nonatomic, assign) NSInteger cve;
#property (nonatomic, copy) NSString *theDescription;
#end
// ***** Subtypes.m file ***** //
#implementation Subtype
+ (NSDictionary*)mts_mapping
{
return #{#"cve": mts_key(cve),
#"description": mts_key(theDescription),
};
}
#end
Finally, as you list above, you can map your JSON, but first you will have to extract the "dictionary" for key Types, which you will map to your "Type" model object.
// Get the json data
NSDictionary * jsonObject = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:&error];
// Extract the JSON dictionary of types.
NSDictionary *jsonType = [jsonObject objectForKey:#"Types"];
// Create a Type object
Type *type = [[Type alloc] init];
// Map JSON contents to the type object with Motis
[type mts_setValuesForKeysWithDictionary:jsonType];
Hoping this fixes your issue.

RLMObject unable to use as a normal object

I have a Product model with the header:
#interface Product : RLMObject <NSCopying,NSCoding>
{
}
#property (nonatomic, strong) NSString *title;
#property (nonatomic, strong) NSString *thumbnailURL;
#property (nonatomic, strong) UIImage *thumbnail;
-(id)initWithInfo:(NSDictionary*)dictionary;
-(UIImage*)getThumbnail;
and implementation:
#implementation Product
-(id)initWithInfo:(NSDictionary*)dictionary
{
self = [self init];
if (self) {
_title = dictionary[#"title"];
_thumbnailURL = dictionary[#"thumbnailURL"];
_thumbnail = [self getThumbnail];
}
return self;
}
-(UIImage*)getThumbnail
{
if (_thumbnail) {
return _thumbnail;
}
//load image from cache
return [self loadImageFromCache];
}
Now, when I try to create a Product object and insert it into Realm, I always get the exception
[RLMStandalone_Product getThumbnail]: unrecognized selector sent to instance 0xcd848f0'
Now, I remove _thumbnail = [self getThumbnail]; and it works fine. But then I get another exception
[RLMStandalone_Product title]: unrecognized selector sent to instance 0xd06d5f0'
when I reload my view. I have created my Product object in the main thread, so it should be fine to using its property and method, isn't it?
Any advice will be appreciated!
Because Realm object properties are backed by the database rather than in-memory ivars, accessing those properties' ivars is not supported. We're currently clarifying our docs to convey this:
Please note that you can only use an object on the thread from which is was created or obtained, ivars shouldn't be accessed directly for any persisted properties, and that getters and setters for persisted properties cannot be overridden.
So to work with Realm, your model should look like this:
#interface Product : RLMObject
#property NSString *title;
#property NSString *thumbnailURL;
#property (nonatomic, strong) UIImage *thumbnail;
#end
#implementation Product
-(UIImage*)thumbnail
{
if (!_thumbnail) {
_thumbnail = [self loadImageFromCache];
}
return _thumbnail;
}
-(UIImage*)loadImageFromCache
{
// Load image from cache
return nil;
}
+(NSArray*)ignoredProperties
{
// Must ignore thumbnail because Realm can't persist UIImage properties
return #[#"thumbnail"];
}
#end
And usage of this model could look like this:
[[RLMRealm defaultRealm] transactionWithBlock:^{
// createInDefaultRealmWithObject: will populate object keypaths from NSDictionary keys and values
// i.e. title and thumbnailURL
[Product createInDefaultRealmWithObject:#{#"title": #"a", #"thumbnailURL": #"http://example.com/image.jpg"}];
}];
NSLog(#"first product's image: %#", [(Product *)[[Product allObjects] firstObject] thumbnail]);
Notice how initWithInfo isn't necessary because RLMObject already has initWithObject: and createInDefaultRealmWithObject: already do this.

How to create objects from JSON NSDictionary

I have a PHP Webservice that returns a JSON string with this format:
[{"latitud":"37.995914","longitud":"-1.139705","nombre":"Miguel de
Unamuno"},{"latitud":"37.995433","longitud":"-1.140143","nombre":"Calle
Pina"},{"latitud":"37.99499","longitud":"-1.140361","nombre":"Calle
Moncayo"},{"latitud":"37.993918","longitud":"-1.139392","nombre":"Calle
Moncayo2"},{"latitud":"37.994588","longitud":"-1.138543","nombre":"Calle
Salvador de Madriaga"}]
In my project, I have a custom class with the next structure:
#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>
#interface PCoordenada : NSObject
#property (nonatomic) CLLocationCoordinate2D *punto;
#property (nonatomic,strong) NSString *nombre;
#end
Then, I´m using other class for the main app:
#import <UIKit/UIKit.h>
#import "PCoordenada.h"
#interface TestViewController : UIViewController
#property (nonatomic,strong) NSData * HTTPResponse;
#property (nonatomic,strong) NSDictionary * dic;
#property (nonatomic,strong) NSMutableArray *arrayCoord;
#property (nonatomic,strong) PCoordenada *coor;
-(IBAction)GetDataFrom:(id)sender;
#end
I wonder how I can make a array of PCoordenada's objects that contain the info of JSON string.
Anyone could help me?
Thanks in advance :)
Do this:
NSData *theData = [NSData dataWithContentsOfURL:[NSURL URLWithString:YOUR_URL]];
NSArray *arrRequests = [NSJSONSerialization JSONObjectWithData:theData options:NSJSONReadingMutableContainers error:nil];
which will put the JSON into an NSArray of objects. Each of these objects is an NSDictionary. So then you just need to loop through the NSArray to get out the NSDictionary of each.
//now let's 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];}
Each NSDictionary that you get from the loop holds the JSON properties as a key in the NSDictionary:
NSString *address = [NSString stringWithString:[dict objectForKey:#"Address"]];
It's also a good practice to use multithreading when reading JSON for better performance.
This article has a very simple to follow how-to. I recommend a read.

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