UIView.hidden不会立即生效

Question

I have a UIViewController with a UITableView and UIView (see blow). When I call hiddenLoadingView at somewhere, the UIView is still showing, then dismiss after 10-20 seconds, why?

- (void)viewDidLoad {
    ....
    self.tableView = [[[UITableView alloc] init] autorelease];
    [self.view addSubview:self.tableView];

    self.loadingView = [[[UIView alloc] init] autorelease];
    [self.view addSubview:self.loadingView];
}

- (void)hiddenLoadingView {
    NSLog(@"%@", [NSNumber numberWithBool:self.loadingView.hidden]);
    [self.loadingView setHidden:YES];
    NSLog(@"%@", [NSNumber numberWithBool:self.loadingView.hidden]);
}

Answer 1

Be sure to call hiddenLoadingView from the main thread. Sounds like you might be calling it from the completion block of some asynchronous method.

Answer 2

you have to call UI changes From main thread.

dispatch_async(dispatch_get_main_queue(), ^{
// do UI related work here
})