Cannot Send Message to Other ViewController

问题

I was messing around in Xcode creating... something... when I needed to send a message to the MainViewController.m from the FlipsideViewController.m. Except, when I do, the ViewController I am sending the message from does not detect the method as existing, despite the fact that I put the method in MainViewController.h. This is the method:

- (void)setAutosave:(BOOL)boolee {
    _autosave = boolee;
}

I have imported the MainViewController into the FlipsideViewController, but as I call it ([NSMainViewController setAutosave:_autosave];), it simply throws an error:

No known class method for selector 'setAutosave:'

I am doing this because FlipsideViewController has a segmented control in it, which tells autosave to be on or off, but it needs to send it's value to the other ViewController.

I really am stumped, help is appreciated.

回答1:

MainViewController is a class, you can't access instance method from a class.

You can add a property to FlipsideViewController, for example:

@property (weak, nonatomic) MainViewController *mainViewController;

Assign your MainViewController instance to mainViewController (how to assign depends on the relationship between your two view controllers), then you can invoke that method by [self.mainViewController setAutosave:_autosave];.

来源：https://stackoverflow.com/questions/21058039/cannot-send-message-to-other-viewcontroller