LGAlertView do not show

[zhouzheren]

LGAlertView *view = [[LGAlertView alloc] initWithTitle:@"Title"
message:@"Message"
style:LGAlertViewStyleActionSheet
buttonTitles:@[@"Button 1", @"Button 2"]
cancelButtonTitle:@"Cancel"
destructiveButtonTitle:@"Destructive"
delegate:self];
view.backgroundColor = [UIColor blackColor];

    [view showAnimated];

[zhouzheren]

[LGAlertViewHelper
animateWithDuration:self.animationDuration
animations:^(void) {
[self showAnimations];

         // -----

         [[NSNotificationCenter defaultCenter] postNotificationName:LGAlertViewShowAnimationsNotification
                                                             object:self
                                                           userInfo:@{kLGAlertViewAnimationDuration: @(self.animationDuration)}];

         if (self.showAnimationsBlock) {
             self.showAnimationsBlock(self, self.animationDuration);
         }

         if (self.delegate && [self.delegate respondsToSelector:@selector(showAnimationsForAlertView:duration:)]) {
             [self.delegate showAnimationsForAlertView:self duration:self.animationDuration];
         }
     }
     completion:^(BOOL finished) {
         if (!hidden) {
             [self showComplete];
         }

         if (completionHandler) {
             completionHandler();
         }
     }];

finished 值为 NO，界面上也没有Alert展示出来， demo中 finished的值是YES，还没有找到根因。

[doasyourself]

// iOS13以上需要设置UIScene，否则不显示
if (@available(iOS 13, *))
{
UIScene *scene = [[[UIApplication sharedApplication].connectedScenes allObjects] firstObject];
self.window.windowScene = scene;
}