如何找到UIWindow里最顶层的ViewController

如何找到UIWindow里最顶层的ViewController

- (UIViewController *)topViewController{
return [self topViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
 
- (UIViewController *)topViewController:(UIViewController *)rootViewController
{
if (rootViewController.presentedViewController == nil) {
return rootViewController;
}
if ([rootViewController.presentedViewController isMemberOfClass:[UINavigationController class]]) {
UINavigationController *navigationController = (UINavigationController *)rootViewController.presentedViewController;
UIViewController *lastViewController = [[navigationController viewControllers] lastObject];
return [self topViewController:lastViewController];
}
UIViewController *presentedViewController = (UIViewController *)rootViewController.presentedViewController;
return [self topViewController:presentedViewController];
}