Swift 2.0 - 无法为“[CLPlacemark]”类型的值添加下标？

Question

我正在尝试将我的 swift 1.2 应用程序转换为 2.0。我已经尝试了一些我在互联网上找到的修复程序，但它不起作用。

错误：Converting to Swift 2.0 - Cannot Subscript a value of type '[CLPlacemark]?'

代码：

 func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation])
{

    CLGeocoder().reverseGeocodeLocation(manager.location!, completionHandler: {(placemarks, error)->Void in

        if (error != nil)
        {
            print("Error: " + error!.localizedDescription)
            return
        }

        if placemarks!.count > 0
        {
            let pm = placemarks[0] as! CLPlacemark
            self.displayLocationInfo(pm)
        }
        else
        {
            print("Error with the data.")
        }
    })
}

Answer 1

已解决:

替换： let pm = placemarks[0] as! CLPlacemark

对于： let pm = placemarks?[0]

Answer 2

或更新 Swift 2.0 安全：

guard let currentPlacemarks = placemarks where currentPlacemarks.count > 0 else {
    // error handling here
    return
}

guard let pm = currentPlacemarks[0] where pm is CLPlacemark else {
    // more error handling
    return
}

self.displayLocationInfo(pm)

Swift 2.0 - 无法为“[CLPlacemark]”类型的值添加下标？

Swift 2.0 - Cannot Subscript a value of type '[CLPlacemark]?'

xcode7

swift2