如何使用 NSUserDefaults 存储字典数组
How to use NSUserDefaults to store an array of dictionaries
正在尝试使用 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?'
Swift 3.x
在 Swift 3 中它已经改变,所以现在需要将其保存为 [Any]
任意数组并使用 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)
}
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
您只需要将其保存为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 来为您完成所有幕后工作,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]]
只需直接从 NSUserDefaults()
调用 .setObject()
方法,它应该可以正常工作。
NSUserDefaults().setObject(theTasks, forKey: "myTasks")
正在尝试使用 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?'
Swift 3.x
在 Swift 3 中它已经改变,所以现在需要将其保存为 [Any]
任意数组并使用 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)
}
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
您只需要将其保存为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 来为您完成所有幕后工作,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]]
只需直接从 NSUserDefaults()
调用 .setObject()
方法,它应该可以正常工作。
NSUserDefaults().setObject(theTasks, forKey: "myTasks")