ios – 执行块后如何返回值？迅速

我想从函数中获取值.有功能块.当块执行时,函数已经返回值.我尝试了很多不同的方法,但他们没有帮助我.我使用了NSOperation和dispatch.该函数始终返回值,直到执行块为止.

var superPlace: MKPlacemark!

 func returnPlaceMarkInfo(coordinate: CLLocationCoordinate2D) -> MKPlacemark? {
    let location = CLLocation(latitude: coordinate.latitude,longitude: coordinate.longitude)
    geocoder.reverseGeocodeLocation(location) { (arrayPlaceMark,error) -> Void in
            if error == nil {
                let firstPlace = arrayPlaceMark!.first!
                let addressDictionaryPass = firstPlace.addressDictionary as! [String : AnyObject]

                self.superPlace = MKPlacemark(coordinate: location.coordinate,addressDictionary: addressDictionaryPass)
            }
        }

    return superPlace
}

解决方法

您不能简单地返回此处,因为reverseGeocodeLocation函数是异步运行的,因此您需要使用自己的完成块：

var superPlace: MKPlacemark!

func getPlaceMarkInfo(coordinate: CLLocationCoordinate2D,completion: (superPlace: MKPlacemark?) -> ()) {
    let location = CLLocation(latitude: coordinate.latitude,error) -> Void in
        if error == nil {
            let firstPlace = arrayPlaceMark!.first!
            let addressDictionaryPass = firstPlace.addressDictionary as! [String : AnyObject]

            self.superPlace = MKPlacemark(coordinate: location.coordinate,addressDictionary: addressDictionaryPass)
            completion(superPlace: superPlace)
        } else {
            completion(superPlace: nil)
        }
    } 
}