objective-c - 视图控制器委托

Question

是否可以从 appDelegate 访问 ViewController 的方法，就像可以与以下代码相反：？

AppDelegate *ad = (AppDelegate *) [[UIApplication sharedApplication] delegate];

当我尝试

ViewController *vc = (ViewController *) [[UIApplication sharedApplication] delegate];

我收到一个错误...

谢谢！

Answer 1

在您的AppDelegate中，假设viewController是您的rootViewController，您可以通过以下方式获取堆栈上所有视图控制器的列表：

NSLog(@"List of current active view controllers:%@", self.viewController.navController.viewControllers);

要访问 viewControllers 中的特定视图控制器：

[[self.viewController.navController.viewControllers objectAtIndex:i] someMethodOfThatViewController]; 

Answer 2

ViewController *vc = (ViewController *)[UIApplication sharedApplication].keyWindow.rootViewController;

或者如果您的代表有属性

YourAppDelegate *ad = (YourAppDelegate*)[UIApplication sharedApplication].delegate;
ViewController *vc = ad.yourViewControllerProperty;