How to use NSUserDefaults to store an array of dic

问题:

Trying to store an array of dictionaries with NSUserDefaults.

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]

Gives error:

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

回答1:

Swift 3.x

In Swift 3 it has changed so now it needs to be saved as [Any] Any Array and use UserDefaults array(forKey:) method to load it:

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)
}

---

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

---

---

Swift 2.x

You just need to save it as a AnyObject array and use NSUserDefaults method arrayForKey to load it:

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)
}

You can also create a computed property with a getter and a setter to do all the work behind the scenes for you as follow:

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]]

回答2:

Just call the .setObject() method directly from NSUserDefaults()and it should work fine.

NSUserDefaults().setObject(theTasks, forKey: "myTasks")