encodeObject（forKey :)和decodeObjectForKey（_ :)有什么区别

Question

这里有两个使用的例子。

// The name is required. If we cannot decode a name string, the initializer should fail.
guard let name = aDecoder.decodeObject(forKey: PropertyKey.name) as? String else {
    os_log("Unable to decode the name for a Meal object.", log: OSLog.default, type: .debug)
    return nil
}

// Because photo is an optional property of Meal, just use conditional cast.
let photo = aDecoder.decodeObjectForKey(PropertyKey.photo) as? UIImage

Answer 1

NSKeyedUnarchiver最初是一个桥接目标c类，因此您可以使用

decodeObjectForKey(_:)迅速<3.0

和

decodeObject(forKey:)迅速> = 3

在内部，它们是同一件事，语法在不断变化，请看一下Thread