arrays - 如何使用 NSUserDefaults 存储字典数组

Question

尝试使用 NSUserDefaults 存储字典数组。

var theTasks: [[String:Any]] = [["num":1,"title":"example","colour":"red"]] 

let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setObject(theTasks, forKey: "myTasks")
    defaults.synchronize()

let selected = theTasks[1]

给出错误:

Cannot convert value of type '[[String:Any]]' to expected argument of type 'AnyObject?'

Answer 1

Swift 3.x

在 Swift 3 中它已经改变，所以现在需要将其保存为 [Any] Any Array 并使用 UserDefaults array(forKey:) 方法加载它:

let theTasks: [Any] = [["num": 1, "title": "example", "colour": "red"]]
UserDefaults.standard.set(theTasks, forKey: "myTasks")
if let loadedTasks = UserDefaults.standard.array(forKey: "myTasks") as? [[String: Any]] {
    print(loadedTasks)
}

<小时/>

var theTasks: [[String: Any]] {
    get {
        return UserDefaults.standard.array(forKey: "myTasks") as? [[String: Any]] ?? []
    }
    set {
        UserDefaults.standard.set(newValue as [Any], forKey: "myTasks")
    }
}

<小时/> <小时/>

Swift 2.x

您只需将其保存为 AnyObject 数组并使用 NSUserDefaults 方法 arrayForKey 加载它:

let theTasks: [AnyObject] = [["num": 1, "title": "example", "colour": "red"]]
NSUserDefaults.standardUserDefaults().setObject(theTasks, forKey: "myTasks")
if let loadedTasks = NSUserDefaults.standardUserDefaults().arrayForKey("myTasks") as? [[String: AnyObject]] {
    print(loadedTasks)
}

您还可以创建一个带有 getter 和 setter 的计算属性来为您完成幕后的所有工作，如下所示:

var theTasks: [[String: AnyObject]] {
    get {
        return NSUserDefaults.standardUserDefaults().arrayForKey("myTasks") as? [[String: AnyObject]] ?? []
    }
    set {
        NSUserDefaults.standardUserDefaults().setObject(newValue as [AnyObject], forKey: "myTasks")
    }
}

print(theTasks)                // [["title": example, "colour": red, "num": 1]]
theTasks[0]["title"] = "another example"

print(theTasks)               // [["title":  another example, "colour": red, "num": 1]]