使用delegate实现回调

• Callback.swift

protocol callbackDelegate{
    func callback(callbackData: String)
}

class Callback {
    var delegate: callbackDelegate?
    
    func callbackMethod() {
        if delegate != nil {
            delegate?.callback("HelloWorld")
        }
    }
}

• ViewController.swift

class ViewController: UIViewController, callbackDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let callback = Callback()
        callback.delegate = self
        callbck.callbackMethod
    }
    func callback(callbackData: String) {
        print(callbackData)
    }

}