存在活动指示器时，在后台禁用选择

我在视图顶部添加活动指示器，并希望在活动指示器打开时在后台禁用选择。同样由于某种原因，在表格视图上显示数据后，我的活动指示器仍会旋转约30-45秒（取决于网络速度）。我为活动指标创建了一个类别。

活动指标类别代码：

- (UIView *)overlayView {
    return objc_getAssociatedObject(self, OverlayViewKey);
}

- (void)setOverlayView:(UIView *)overlayView {
    objc_setAssociatedObject(self, OverlayViewKey, overlayView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (void)showActivityIndicatorForView:(UIView *)view {
    self.overlayView.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.5];
    self.center = self.overlayView.center;
    [view setUserInteractionEnabled:NO];
    [[UIApplication sharedApplication] beginIgnoringInteractionEvents];
    [self.overlayView setUserInteractionEnabled:NO];
    [self startAnimating];
    [self.overlayView addSubview:self];
    [view addSubview:self.overlayView];
    [view bringSubviewToFront:self.overlayView];
    self.hidesWhenStopped = YES;
    self.hidden = NO;

}

- (void)hideActivityIndicatorForView:(UIView *)view {
    [self stopAnimating];
    [self.overlayView setUserInteractionEnabled:YES];
    [self.overlayView removeFromSuperview];
    [[UIApplication sharedApplication] endIgnoringInteractionEvents];
    [view setUserInteractionEnabled:YES];
}

表格视图控制器中的用法：

@interface MyTableViewController()
@property (nonatomic, strong) UIActivityIndicatorView *activityIndicator;
@end

@implementation MyTableViewController
- (id) initWithSomething:(NSString *)something {
    self = [super init];

    if (self) {
        self.activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
        self.activityIndicator.overlayView = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];
    }
    return self;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    [self getDataServiceRequest];
    [self.activityIndicator showActivityIndicatorForView:self.navigationController.view];
}

- (void)requestCompletionCallBack sender:(ServiceAPI *)sender {
// Do something here with the data
    [self.activityIndicator hideActivityIndicatorForView:self.navigationController.view];

    dispatch_async(dispatch_get_main_queue(), ^{
        [self.tableView reloadData];
    });
}
@end

我在这里做错了什么？为什么在活动指示器打开时甚至在禁用用户交互之后，我仍然能够在后台选择数据。