Custom delegate method doesn't get called

Question

So, I'm following this answer in trying to pass data between two classes in an iOS project without storyboards. I'm trying to abstract all my server calls in a different class, so the ViewControllers don't get too cramped. I have an OfferRequest class, which handles the server requests and declares the protocol:

@protocol OfferRequestDelegate <NSObject>

-(void)addOfferRequest: (OfferRequest *)request dataFromRequest: (NSMutableArray *)data;

@end

@interface OfferRequest : NSObject <LocationManagerDelegate, NSURLConnectionDataDelegate>

@property (nonatomic, weak) id <OfferRequestDelegate> delegate;
@end

The idea is to call addOfferRequest: dataFromRequest in connectionDidFinishLoading, set the data as the result from the request and pass it on to the ViewController.

In OfferRequest.m:

-(void)connectionDidFinishLoading:(NSURLConnection *)connection {

    NSMutableArray *result = [NSJSONSerialization JSONObjectWithData:receivedData options:kNilOptions error:nil];
    [self.delegate addOfferRequest:self dataFromRequest:result];

}

I declare my ViewController as a delegate for the OfferRequest:

@interface CategorySuggestionViewController : UIViewController <OfferRequestDelegate>

Initialize the OfferRequest object and set it's delegate:

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    offer = [OfferRequest new];
    offer.delegate = self;
}

And then implement the delegate method:

-(void)addOfferRequest:(OfferRequest *)request dataFromRequest:(NSMutableArray *)data {
    NSLog(@"received data = %@", data);
}

But it never gets called. What am I missing ?

Answer 1

try this...

your OfferRequest class like below i have given name it as connectionClass

connectionClass.h

@protocol connectionDelegate <NSObject>
-(void)connectionSucceed:(NSData *)data;
-(void)connectionFailed:(NSError *)error;
@end

#import <Foundation/Foundation.h>

@interface connectionClass : NSObject
{
    id<connectionDelegate> delegate;
    NSMutableData *receivedData;
    NSString *encodedString;
    NSMutableURLRequest *theRequest;
    NSURL *url;
    NSString *length;
    NSURLConnection *Connect;

}
@property(nonatomic, retain) id<connectionDelegate> delegate;
@property(nonatomic, retain) NSMutableData *receivedData;
- (void)connectionWithURL:(NSString *)URL;
@end

connectionClass.m

#import "connectionClass.h"

@implementation connectionClass
@synthesize delegate, receivedData;
- (void)connectionWithURL:(NSString *)URL
{
    url=[[NSURL alloc] initWithString:[self urlencode:URL]];
    theRequest= [NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60];
    [theRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    length = [NSString stringWithFormat:@"%lu", (unsigned long)[URL length]];
    [theRequest setValue:length forHTTPHeaderField:@"Content-Length"];
    [theRequest setHTTPMethod:@"POST"];

    [theRequest setHTTPBody:[URL dataUsingEncoding:NSUTF8StringEncoding]];

    Connect = [NSURLConnection connectionWithRequest:theRequest delegate:self];

    if (Connect)
    {
        self.receivedData = [NSMutableData data];
    }
    else
    {
        NSError *error;
        [self.delegate connectionFailed:error];
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    [self.receivedData setLength:0];
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [self.receivedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    [self.delegate connectionSucceed:self.receivedData];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    [self.delegate connectionFailed:error];
}
-(NSString *) urlencode: (NSString *) string
{
    encodedString = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)string, NULL, (CFStringRef)@"", kCFStringEncodingUTF16));
    return encodedString;
}


@end

don't forget to import your connectionclass and delegate

@interface yourclass : UIViewController<connectionDelegate>

Initialize the OfferRequest object and set it's delegate:

-(void)viewWillAppear:(BOOL)animated
{
    connection = [[connectionClass alloc]init];
    connection.delegate = self;
     [connection connectionWithURL:[NSString stringWithFormat:@"pass your url here"]];
}

The delegate method will have your values

-(void)connectionSucceed:(NSData *)data
{
    NSError *error;
    self.dictionary = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:&error];
    //nslog your data
}

//Connection failure
-(void)connectionFailed:(NSError *)error
{
  //handle error message
}

Answer 2

Ok, I don't know where the problem exactly was, but what I did to fix it, was to create a new init method, where I pass the delegate:

-(instancetype)initWithDelegate: (id<OfferRequestDelegate>) delegate {
    self = [super init];

    if (self) {
        self.delegate = delegate;
    }

    return self;
}

So I initialize the OfferRequest object in the VC and pass self and now it works.

Answer 3

I guess delegate should be a pointer object and not the object.

It may be help you

@property (nonatomic, weak) NSObject <OfferRequestDelegate> *delegate;

and make should your delegate is been set, i.e. make sure your code below is getting called.

 [self.delegate addOfferRequest:self dataFromRequest:result];