我想为NSDictionary
编写扩展名,因此我可以轻松地从数据中创建它。我是这样写的:
extension Dictionary {
init?(data: NSData?) {
guard let data = data else { return nil }
// TODO: This leaks.
if let json = (try? NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions())) as? Dictionary {
self = json
}
else { return nil }
}
}
无法找出泄漏的原因。有什么想法吗?
答案 0 :(得分:6)
在我的情况下,当我试图从中获取子字典时,事实证明问题出现在这个字典的后一种用法中。准确地说,在这段代码中:
var location: CLLocation? = nil
if let geometryDictionary = json["geometry"], locationDictionary = geometryDictionary["location"], latitude = locationDictionary["lat"] as? CLLocationDegrees, longitude = locationDictionary["lng"] as? CLLocationDegrees {
location = CLLocation(latitude: latitude, longitude: longitude)
}
问题是我收到了geometryDictionary和locationDictionary引用而没有指定它们的类型,所以编译器假设它们是AnyObject。我仍然可以从字典中获取它们的值,因此代码可以工作。当我向他们添加类型时,泄漏就停止了。
var location: CLLocation? = nil
if let geometryDictionary = json["geometry"] as? [String : AnyObject], locationDictionary = geometryDictionary["location"] as? [String : AnyObject], latitude = locationDictionary["lat"] as? CLLocationDegrees, longitude = locationDictionary["lng"] as? CLLocationDegrees {
location = CLLocation(latitude: latitude, longitude: longitude)
}