Overlay not scrolling with UITableView - iOS

问题

I have a UITableView class that uses the following methods to call a loading overlay when going to the next screen. The problem is that this loading screen does not scroll with the list... So if you scroll a little bit and click on something, the loading screen doesn't show (because it's at the top). How can I get the loading screen to stay on top of the UITableView at all times? Please know that each UITableView is contained within a UINavBar, which is contained within a UITabBar. Here is my code:

-(void)createLoadScreen
{
    CGRect screenRect = [self.view bounds];
    CGRect overlayFrame = CGRectMake(0.0, 0.0, screenRect.size.width, screenRect.size.height);
    overlay = [[UIView alloc] initWithFrame:overlayFrame];
    overlay.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0.7];
    CGRect frame = CGRectMake(screenRect.size.width / 2 - 25.0, screenRect.size.height / 2 - 70, 25.0, 25.0);
    loading = [[UIActivityIndicatorView alloc] initWithFrame:frame];
    [loading setActivityIndicatorViewStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [loading sizeToFit];
    loading.autoresizingMask = (UIViewAutoresizingFlexibleLeftMargin |
                                UIViewAutoresizingFlexibleRightMargin |
                                UIViewAutoresizingFlexibleTopMargin |
                                UIViewAutoresizingFlexibleBottomMargin);
    loading.hidesWhenStopped = YES;
    [overlay addSubview:loading];
}

-(void)showActivityIndicator
{ 
    [self.view addSubview:overlay];
    [loading startAnimating];
}

-(void)removeActivityIndicator {
    [loading stopAnimating];
    [overlay removeFromSuperview];
}

回答1:

Are you using a UITableViewController?

You should be able to fix your issue by adding the overlay view to the table's superview instead of the table view itself. This way your overlay is actually above and separate from your scrolling table view

-(void)showActivityIndicator
{ 
    [[self.view superview] addSubview:overlay];
    [loading startAnimating];
}

来源：https://stackoverflow.com/questions/10423399/overlay-not-scrolling-with-uitableview-ios