+ (instancetype)findBestViewController:(UIViewController *)vc {
if (vc.presentedViewController) {
// Return presented view controller
return [UIViewController findBestViewController:vc.presentedViewController];
} else if ([vc isKindOfClass:[UISplitViewController class]]) {
// Return right hand side
UISplitViewController* svc = (UISplitViewController*) vc;
if (svc.viewControllers.count > 0) {
return [UIViewController findBestViewController:svc.viewControllers.lastObject];
} else {
return vc;
}
} else if ([vc isKindOfClass:[UINavigationController class]]) {
// Return top view
UINavigationController* svc = (UINavigationController*) vc;
if (svc.viewControllers.count > 0) {
return [UIViewController findBestViewController:svc.topViewController];
} else {
return vc;
}
} else if ([vc isKindOfClass:[UITabBarController class]]) {
// Return visible view
UITabBarController *svc = (UITabBarController *)vc;
if (svc.viewControllers.count > 0) {
return [UIViewController findBestViewController:svc.selectedViewController];
} else {
return vc;
}
} else {
// Unknown view controller type, return last child view controller
return vc;
}
}
+ (instancetype)currentViewController {
UIViewController *viewController = [UIApplication sharedApplication].keyWindow.rootViewController;
return [self findBestViewController:viewController];
}