How to call private class function from selector in Swift.?

Question

Currently i'm doing like this,

Calling selector as:

NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: "startAnimation:", userInfo: loadingView, repeats: true)

Selector method is as:

private class func startAnimation(timer:NSTimer){
    var loadingCircularView = timer.userInfo as UIView
}

I'm getting warning, and app crashes:

warning: object 0x67c98 of class ‘ClassName’ does not implement methodSignatureForSelector: -- trouble ahead Unrecognized selector +[ClassName startAnimation:]

Answer 1

1. You can write your function as follow :

@objc private class func startAnimation() {}

or

dynamic private class func startAnimation() {}  // not recommended

When you declare a swift function as dynamic, you made it seems like a Objective-C function (Objective-C follows Dynamic Dispatch), or we can say, the function is a Dynamic Dispatch Function right now, which can be called in Selector.

But in this case, we just need to let this function has a Dynamic Feature, so declare it as @objc is enough.

2. If you write your function as

@objc private func xxxxx(){}

the target in NSTimer should be self, but if you write your function as

@objc private class func xxxx(){} // Assuming your class name is 'MyClass'

the target in NSTimer should be MyClass.self.