- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.proArray = [[NSMutableArray alloc]init];

    GCDVC2* __weak weakSelf = self;

    self.postGCDBlock = ^{

        GCDVC2* __strong strongSelf = weakSelf;

        [strongSelf.proArray removeObject:@"3"];
        NSLog(@"%@",strongSelf.proArray);
        [strongSelf.activityIndicator stopAnimating];
    };

    self.addObjectsBlock = ^{

        GCDVC2* __strong strongSelf = weakSelf;

        [strongSelf.proArray addObject:@"2"];
        [NSThread sleepForTimeInterval:10];

        dispatch_async(dispatch_get_main_queue(),strongSelf.postGCDBlock);
    };
}