Objective-C：如何调用实例方法

Question

I need to call a method I have defined as:

-(IBAction)next:(id)sender{ 
...

}

I want to call it in -[UIViewController viewDidload]

How can I call this method programmatically?

Answer 1

[self next:nil];

• self is the object receiving the message, assuming -next: is defined in the same class as -viewDidLoad .
• next: is the name of the message (method).
• Since you don't use sender , pass the argument nil , meaning "nothing".

If -next: is defined in the App delegate but -viewDidLoad in some view controller, use

[UIApplication sharedApplication].delegate

to refer to the app delegate. So the statement becomes

[[UIApplication sharedApplication].delegate next:nil];