从app delegate调用视图控制器方法

I'm trying to call a method in the view controller from the app delegate, but Xcode says No known class method for selector 'myMethodHere'. Here's my code:

我试图从app委托调用视图控制器中的方法，但是Xcode说选择器'myMethodHere'没有已知的类方法。这是我的代码：

AppDelegate.m:

AppDelegate.m：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    [..]
            [MainViewController myMethodHere];
    [..]
    return YES;
}

MainViewController.m:

MainViewController.m：

-(void) myMethodHere {
     [..]
}

5 个解决方案

#1

I would try

我会尝试

MainViewController * vc = [[MainViewController alloc]init];
[vc myMethodHere];
[vc release];

Make sure to import your MainViewController in your app delegate .m file
确保在app delegate .m文件中导入MainViewController
make sure you add "myMethodHere" to your MainViewController .h file
确保将“myMethodHere”添加到MainViewController .h文件中

#2

You are trying to call a class method when you want to call an instance method. If the view controller is the root view controller, then you should be able to call it thus:

您想要调用实例方法时尝试调用类方法。如果视图控制器是根视图控制器，那么您应该可以这样调用它：

UIWindow *window = [UIApplication sharedApplication].keyWindow;
MainViewController *rootViewController = window.rootViewController;
[rootViewController myMethodHere];

If it's not the root view controller then you'll have to find some other way of getting hold of the instance and then calling the method as in the last line above.

如果它不是根视图控制器，那么你将不得不找到一些其他方法来获取实例，然后调用上面最后一行中的方法。

#3

If you want to access to a view controller on a story board, you may use this block of code from the AppDelegate:

如果要访问故事板上的视图控制器，可以使用AppDelegate中的以下代码块：

MainViewController *rootViewController = (MainViewController*)self.window.rootViewController;
[rootViewController aMethod];

Remember to add the import.

请记住添加导入。

#4

In Swift, you can write it like this

在Swift中，你可以这样写

    UIApplication.sharedApplication().keyWindow?.rootViewController?.yourMethodName()

#5

Try to write

试着写

 -(void) myMethodHere;

in MainViewController.h

在MainViewController.h中

#1