gistfile1.m

// An implementation.

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    
//    if (!self.isThingsSaved) {
//        [self saveThings];
//    }
    [self saveThings];
}

- (void)saveThings
{
    __weak typeof(self) weakSelf = self;
    [thing saveRow:@{kTHTParseKeyPersonRecordId: @(self.person.recordID),
                     kTHTParseKeyOriginalImage: originalImage ?: [NSNull null],
                     kTHTParseKeyOriginalThumbnail: originalThumbnail ?: [NSNull null],
                     kTHTParseKeyThings: self.things}
        usingBlock:^(BOOL succeeded, PFObject *aThing, NSError *error) {
            __strong typeof(weakSelf) strongSelf = weakSelf;
            // TODO: handle errors properly (jfas).
            if (error) {
                NSLog(@"[ERROR] - %s: %@", __PRETTY_FUNCTION__, [NSString stringWithFormat:@"\n%@\n%@", [error localizedDescription], error.userInfo]);
                return;
            }
             
            if (succeeded) {
//                strongSelf.thingsSaved = YES;
                
                if (strongSelf.delegate && [strongSelf.delegate respondsToSelector:@selector(thingAddedSuccessfully:)]) {
                    [strongSelf.delegate thingAddedSuccessfully:(THTThing *) aThing];
                }
            }
        }];
}

// strongSelf is nil after viewWillDisappear is executed and the block is call, why?.