Ios SVProgressHUD如何在下一个ViewController中显示

我有一个带有一些项目的TableViewController，然后有一个filterViewController，其中根据值过滤TableViewController中的数据。它是用UISwitch制成的。无论如何，我想问一下，当我使用过滤数组从filterViewController返回时，如何将SVProgressHUD添加到操作中。在tableView中过滤和显示它们需要几秒钟的时间。我已经尝试过dispatch_async，它甚至不显示HUD。我在filterViewController中有一个iAction for按钮，用于确认值并将其发送到TableViewController

如果我将HUD添加到filterViewController中的操作，HUD不会显示在TableViewController中

filtervewcontroller.m

TableViewController.m

---

明白了。为TableViewController中的过滤器生成布尔值。这比我想象的要容易

-(IBAction)Done:(id)sender{

    [self willMoveToParentViewController:nil];

    [self.navigationController popViewControllerAnimated:YES];


}

- (void)filterController:(filterViewController *)controller didEditConfig:(NSMutableDictionary *)config
{
    [SVProgressHUD showWithMaskType:SVProgressHUDMaskTypeGradient];
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        // time-consuming task

        self.konfigg = config;


        NSSet *filter = [config keysOfEntriesPassingTest:
                         ^BOOL (id key, NSNumber *value, BOOL *stop) {
                             return [value boolValue];

                         }];

        NSLog(@"filtered keys: %@ (%lu of %lu)", filter, (unsigned long)filter.count, (unsigned long)config.count);

        PFQuery *query = [PFQuery queryWithClassName:@"Class"];
        [query addDescendingOrder:@"createdAt"];
        [query whereKey:@"eventDay" containedIn:[filter allObjects]];

        [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {

            if (!error) {
                self.itemss = [objects mutableCopy];
                [self.MainTable reloadData];

                NSLog(@"Got filtered results %@ (%lu)", objects, (unsigned long)objects.count);
            }}
         ];
        dispatch_async(dispatch_get_main_queue(), ^{
            [SVProgressHUD dismiss];
        });
    });

}