从app delegate调用UIViewController方法 [英] Calling UIViewController method from app delegate

问题描述

我知道这个问题有重复，但我的情况有所不同。

I know there are duplicates of this question but my situation is different here.

当用户返回家中时（void）applicationDidEnterBackground 从 AppDelegate 类调用。但是一旦用户按下主页按钮，我不希望用户再次看到这个视图控制器，所以我有一个名为（void）goToBeginning 的方法切换到另一个视图控制器。我希望能够从AppDelegate调用此方法。我真的不想使用 NotificationCenter 。此处选择的解决方案：
从app delegate调用视图控制器方法
对我来说不起作用，因为它初始化了新对象，而我希望能够调用已经在视图中的对象。我怎样才能做到这一点？我使用的是iOS 7和XCode 5.

When user goes back to the home (void)applicationDidEnterBackground gets invoked from the AppDelegate class. However once user presses home button, I don't want user to see this view controller again, so I have a method named (void)goToBeginning that switches to another view controller. I want to be able to call this method from AppDelegate. I don't really want to use NotificationCenter for this. Also the picked solution here: Calling view controller method from app delegate does not work for me as it initialises new object whereas I want to be able to call an object that is already in the view. How can I do that? I am using iOS 7 and XCode 5.

推荐答案

1. 通知。但是你不想要这个。


2. 你可以在 AppDelegate中获得对 viewController 的引用。在（void）applicationDidEnterBackground

中调用（void）goToBeginning 方法

例如：在你的 ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    appDelegate.myViewController = self;
}

在你的 AppDelegate ：

@class MyViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (weak, nonatomic) MyViewController *myViewController;

@end

并且在 AppDelegate 的实现：

- (void)applicationDidEnterBackground:(UIApplication *)application
{
    [self.myViewController goToBeginning];
}

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