ios - 将值传递给闭包函数

查看此代码：

func getReversedGeocodeLocation(location: CLLocation, completionHandler: @escaping ()->()) {
    CLGeocoder().reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in

        if error != nil {
            print("Reverse geocoder failed with error" + error!.localizedDescription)
            return
        }

        if placemarks != nil {
            if placemarks!.count > 0 {
                let pm = placemarks![0]
                if let addressDictionary: [AnyHashable: Any] = pm.addressDictionary,
                let addressDictionaryFormatted = addressDictionary["FormattedAddressLines"] {
                    let address = (addressDictionaryFormatted as AnyObject).componentsJoined(by: ", ")
                    self.addressInViewController = address
                }
                completionHandler()
            }
        } else {
            print("Problem with the data received from geocoder")
        }
    })
}

在视图控制器中

override func viewDidLoad() {
    var addressInViewController = String()
    getReversedGeocodeLocation(location: location, completionHandler: {
        print("After geo finished")
    })
}

这是一个使用闭包的简单例子。如您所见，当反向geo完成时，它将更新在函数本身外部定义的addressInViewController变量。当谈到闭包时，我有点困惑，但我知道它实际上是将另一个函数作为参数传入一个函数。因此，我可以传入类似（String:x）->（）的内容，而不是从主reverse geo函数填充地址变量并将其传递给它的位置（）->（）？我试过这么做，但它说“x”是未定义的。如果这是可以实现的，那么我想我可以使用闭包以更好的方式分离我的代码。
谢谢，祝你有个愉快的一天：）

最佳答案

像这样定义你的方法

func getReversedGeocodeLocation(location: CLLocation, completionHandler: @escaping (_ value : Any)->()) {
    CLGeocoder().reverseGeocodeLocation(location, completionHandler: {(placemarks, error) -> Void in

        if error != nil {
            print("Reverse geocoder failed with error" + error!.localizedDescription)
            return
        }

        if placemarks != nil {
            if placemarks!.count > 0 {
                let pm = placemarks![0]
                if let addressDictionary: [AnyHashable: Any] = pm.addressDictionary,
                let addressDictionaryFormatted = addressDictionary["FormattedAddressLines"] {
                    let address = (addressDictionaryFormatted as AnyObject).componentsJoined(by: ", ")
                    self.addressInViewController = address
                }
                completionHandler(address)
            }
        } else {
            print("Problem with the data received from geocoder")
        }
    })
}

override func viewDidLoad() {
    var addressInViewController = String()
    getReversedGeocodeLocation(location: location, completionHandler: { (_ values : Any) in
         self. addressInViewController = values

    })
}

根据需要将数据类型设置为Value。