使用 NSUserDefaults 保存标签的文本
Saving a label's text using NSUserDefaults
我正在尝试使用 NSUserDefaults 保存我的分数。我希望它保存标签文本，所以当你打开它时，文本仍然存在。我不知道代码应该放在哪里。非常感谢任何帮助。
这是我的代码：
import UIKit
import AVFoundation
struct Question {
var Question : String!
var Answers : [String]!
var Answer : Int!
}
class ViewController: UIViewController {
@IBOutlet weak var highScoreLbl: UILabel!
@IBOutlet var Buttons: [UIButton]!
@IBOutlet weak var QLabel: UILabel!
@IBOutlet weak var Label: UILabel!
@IBOutlet weak var incorrectLabel: UILabel!
@IBOutlet weak var timerLabel: UILabel!
@IBOutlet weak var theEnd: UILabel!
@IBOutlet weak var continueButton: UIButton!
@IBOutlet weak var button1: UIButton!
@IBOutlet weak var button2: UIButton!
@IBOutlet weak var button3: UIButton!
@IBOutlet weak var button4: UIButton!
var scoreLbl = UILabel()
var score = Int()
var Questions = [Question]()
var QNumber = Int()
var AnswerNumber = Int()
var wrongAnswers = Int()
var highScore = 0
override func viewDidLoad() {
super.viewDidLoad()
Questions = [Question(Question: "What is the Biggest Hit of Bing Crosby?" , Answers: ["Swinging on a Star", "Now is the Hour", "White Christmas", "Beautiful Dreamer"], Answer: 2),
Question(Question: "What is Elvis Presely's Middle Name?", Answers: ["Aaron", "Micheal", "George", "Matthew"], Answer: 0),
Question(Question: "How Many Oscars did Titanic win?", Answers: ["5", "7", "10", "11"], Answer: 3),
Question(Question: "From which country did Pitta Bread originate?", Answers: ["Spain", "France", "Greece", "Russia"], Answer: 2),
Question(Question: "What is the largest living creature on Earth?", Answers: ["Whale", "Shark", "Sea Turtle", "Alligator"], Answer: 0),
Question(Question: "What does ATM stand for?", Answers: ["Automatic Treasure Machine", "Automatic Tax Machine", "Anti Tax Machine", "Automatic Teller Machine"], Answer: 3),
Question(Question: "What's the world's second largest French speaking city?", Answers: ["Paris", "Montreal", "Versailles", "Québec"], Answer: 1),
Question(Question: "What Country is the largest producer of Olive Oil?", Answers: ["Italy", "France", "Greece", "Spain"], Answer: 3),
Question(Question: "How long is the Great Wall of China?", Answers: ["3200 miles", "4000 miles", "2000 kilometers", "4500 miles"], Answer: 1),
Question(Question: "Who is on the 10 dollar bill?", Answers: ["George Washington", "Thomas Jefferson", "Alexander Hamilton", "John Adams" ], Answer: 2),
Question(Question: "How many World Series did Yogi Berra win as a player?", Answers: ["11", "10", "5", "7" ], Answer: 1),
Question(Question: "Which three countries hosted the Winter Olympics during the 1990's?", Answers: ["Norway, France, Russia", "US, Sweeden, Canada", "Japan, Canada, Germany", "Slovenia, France, South Korea" ], Answer: 0),]
scoreLbl = UILabel(frame: CGRectMake(35, 45, 77, 45))
scoreLbl.textAlignment = NSTextAlignment.Center
scoreLbl.text = "-1"
self.view.addSubview(scoreLbl)
PickQuestions()
saveHighScore()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func PickQuestions(){
score++
scoreLbl.text = "\(score)"
if Questions.count > 0{
QNumber = random() % Questions.count
QLabel.text = Questions[QNumber].Question
AnswerNumber = Questions[QNumber].Answer
for i in 0..<Buttons.count{
Buttons[i].setTitle(Questions[QNumber].Answers[i], forState: UIControlState.Normal)
}
Questions.removeAtIndex(QNumber)
}
else{
theEnd.text = "You Win!"
theEnd.alpha = 1
button1.enabled = false
button2.enabled = false
button3.enabled = false
button4.enabled = false
func reset(){
let alert = UIAlertController(title: "You Win", message: "Click Restart To Play Again", preferredStyle: UIAlertControllerStyle.Alert)
let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil)
alert.addAction(okAction)
presentViewController(alert, animated: true, completion: nil)
}
reset()
}
saveHighScore()
incorrectLabel.alpha = 0
}
func saveHighScore(){
if score >= highScore {
highScore = score
highScoreLbl.text = "High Score: " + String(score)
}
else{}
}
@IBAction func Btn1(sender: AnyObject) {
if AnswerNumber == 0{
PickQuestions()
}
else{
incorrectLabel.text = "You are incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn2(sender: AnyObject) {
if AnswerNumber == 1{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn3(sender: AnyObject) {
if AnswerNumber == 2{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn4(sender: AnyObject) {
if AnswerNumber == 3{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
}
您可以使用 属性 个观察者 来完成。每次你设置分数时，你的 didSet 块都会检查你的分数是否大于之前的最高分，如果是，它将 运行 并将你的最高分存储到你的 NSUserDefaults 中。
"Property observers observe and respond to changes in a property’s
value. Property observers are called every time a property’s value is
set, even if the new value is the same as the property’s current
value."
有关 属性 观察者的更多信息：Swift Programming Language Guide
var userDefaults = NSUserDefaults.standardUserDefaults()
var score: Int = 0 {
didSet {
self.scoreLbl.text = "\(score)"
if score > highScore {
// you could just as easily call a function here
userDefaults.setInteger(score, forKey: "CurrentHighScore")
//userDefaults.synchronize() // slow and unnecessary!
}
}
}
然后在你的 viewDidLoad 或 viewWillAppear 中检索你的高分值：
override func viewDidLoad() {
self.scoreLbl.text = userDefaults.integerForKey("CurrentHighScore")
}
不需要同步 iOS 8 及更高版本：
来自 http://www.codingexplorer.com/nsuserdefaults-a-swift-introduction/
Calling synchronize in an iOS 8 app will unnecessarily slow your
program, without giving a significant benefit. I’ll let the document
speak for itself about the Performance Tradeoffs in NSUserDefaults:
"Reading from NSUserDefaults is extremely fast. It will cache values to
avoid reading from the disk, and takes about 0.5 microseconds to do
[[NSUserDefaults standardUserDefaults] boolForKey:] on a 2012 MacBook
Pro. It’s generally unnecessary (and even undesirable since it
prevents picking up new values) to cache the result of reading from
preferences.
However, writing to NSUserDefaults is a bit slower. In general, expect
it to take roughly as long as using NSPropertyListSerialization to
convert your key and value to plist data, plus a few 10s of
microseconds. For this reason, as well as memory usage, it’s generally
best to store relatively small data in CFPreferences."
你应该把改变乐谱所带来的一切结合到一个方法中。这将使您更容易管理，并使代码更清晰
func saveScore(newScore:Int){
// Set the value of newScore to the class variable score
score = newScore
// Set the value of newScore to the scoreLbl
scoreLbl.text = "\(newScore)"
// Fetch User Defauls
let userDefaults = NSUserDefaults.standardUserDefaults()
// Save newScore value to the userDefaults
userDefaults.setInteger(newScore, forKey: "score")
// Synchronize userDefaults
userDefaults.synchronize()
}
该方法会设置分数，将其放入标签中，同时将分数保存到用户默认值中。只要你想更新分数而不是直接改变分数的值，就调用这个方法。
我正在尝试使用 NSUserDefaults 保存我的分数。我希望它保存标签文本，所以当你打开它时，文本仍然存在。我不知道代码应该放在哪里。非常感谢任何帮助。
这是我的代码：
import UIKit
import AVFoundation
struct Question {
var Question : String!
var Answers : [String]!
var Answer : Int!
}
class ViewController: UIViewController {
@IBOutlet weak var highScoreLbl: UILabel!
@IBOutlet var Buttons: [UIButton]!
@IBOutlet weak var QLabel: UILabel!
@IBOutlet weak var Label: UILabel!
@IBOutlet weak var incorrectLabel: UILabel!
@IBOutlet weak var timerLabel: UILabel!
@IBOutlet weak var theEnd: UILabel!
@IBOutlet weak var continueButton: UIButton!
@IBOutlet weak var button1: UIButton!
@IBOutlet weak var button2: UIButton!
@IBOutlet weak var button3: UIButton!
@IBOutlet weak var button4: UIButton!
var scoreLbl = UILabel()
var score = Int()
var Questions = [Question]()
var QNumber = Int()
var AnswerNumber = Int()
var wrongAnswers = Int()
var highScore = 0
override func viewDidLoad() {
super.viewDidLoad()
Questions = [Question(Question: "What is the Biggest Hit of Bing Crosby?" , Answers: ["Swinging on a Star", "Now is the Hour", "White Christmas", "Beautiful Dreamer"], Answer: 2),
Question(Question: "What is Elvis Presely's Middle Name?", Answers: ["Aaron", "Micheal", "George", "Matthew"], Answer: 0),
Question(Question: "How Many Oscars did Titanic win?", Answers: ["5", "7", "10", "11"], Answer: 3),
Question(Question: "From which country did Pitta Bread originate?", Answers: ["Spain", "France", "Greece", "Russia"], Answer: 2),
Question(Question: "What is the largest living creature on Earth?", Answers: ["Whale", "Shark", "Sea Turtle", "Alligator"], Answer: 0),
Question(Question: "What does ATM stand for?", Answers: ["Automatic Treasure Machine", "Automatic Tax Machine", "Anti Tax Machine", "Automatic Teller Machine"], Answer: 3),
Question(Question: "What's the world's second largest French speaking city?", Answers: ["Paris", "Montreal", "Versailles", "Québec"], Answer: 1),
Question(Question: "What Country is the largest producer of Olive Oil?", Answers: ["Italy", "France", "Greece", "Spain"], Answer: 3),
Question(Question: "How long is the Great Wall of China?", Answers: ["3200 miles", "4000 miles", "2000 kilometers", "4500 miles"], Answer: 1),
Question(Question: "Who is on the 10 dollar bill?", Answers: ["George Washington", "Thomas Jefferson", "Alexander Hamilton", "John Adams" ], Answer: 2),
Question(Question: "How many World Series did Yogi Berra win as a player?", Answers: ["11", "10", "5", "7" ], Answer: 1),
Question(Question: "Which three countries hosted the Winter Olympics during the 1990's?", Answers: ["Norway, France, Russia", "US, Sweeden, Canada", "Japan, Canada, Germany", "Slovenia, France, South Korea" ], Answer: 0),]
scoreLbl = UILabel(frame: CGRectMake(35, 45, 77, 45))
scoreLbl.textAlignment = NSTextAlignment.Center
scoreLbl.text = "-1"
self.view.addSubview(scoreLbl)
PickQuestions()
saveHighScore()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func PickQuestions(){
score++
scoreLbl.text = "\(score)"
if Questions.count > 0{
QNumber = random() % Questions.count
QLabel.text = Questions[QNumber].Question
AnswerNumber = Questions[QNumber].Answer
for i in 0..<Buttons.count{
Buttons[i].setTitle(Questions[QNumber].Answers[i], forState: UIControlState.Normal)
}
Questions.removeAtIndex(QNumber)
}
else{
theEnd.text = "You Win!"
theEnd.alpha = 1
button1.enabled = false
button2.enabled = false
button3.enabled = false
button4.enabled = false
func reset(){
let alert = UIAlertController(title: "You Win", message: "Click Restart To Play Again", preferredStyle: UIAlertControllerStyle.Alert)
let okAction = UIAlertAction(title: "Ok", style: UIAlertActionStyle.Default, handler: nil)
alert.addAction(okAction)
presentViewController(alert, animated: true, completion: nil)
}
reset()
}
saveHighScore()
incorrectLabel.alpha = 0
}
func saveHighScore(){
if score >= highScore {
highScore = score
highScoreLbl.text = "High Score: " + String(score)
}
else{}
}
@IBAction func Btn1(sender: AnyObject) {
if AnswerNumber == 0{
PickQuestions()
}
else{
incorrectLabel.text = "You are incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn2(sender: AnyObject) {
if AnswerNumber == 1{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn3(sender: AnyObject) {
if AnswerNumber == 2{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
@IBAction func Btn4(sender: AnyObject) {
if AnswerNumber == 3{
PickQuestions()
}
else{
incorrectLabel.text = "You are Incorrect!"
incorrectLabel.alpha = 1
score--
scoreLbl.text = "\(score)"
}
}
}
您可以使用 属性 个观察者 来完成。每次你设置分数时，你的 didSet 块都会检查你的分数是否大于之前的最高分，如果是，它将 运行 并将你的最高分存储到你的 NSUserDefaults 中。
"Property observers observe and respond to changes in a property’s value. Property observers are called every time a property’s value is set, even if the new value is the same as the property’s current value."
有关 属性 观察者的更多信息：Swift Programming Language Guide
var userDefaults = NSUserDefaults.standardUserDefaults()
var score: Int = 0 {
didSet {
self.scoreLbl.text = "\(score)"
if score > highScore {
// you could just as easily call a function here
userDefaults.setInteger(score, forKey: "CurrentHighScore")
//userDefaults.synchronize() // slow and unnecessary!
}
}
}
然后在你的 viewDidLoad 或 viewWillAppear 中检索你的高分值：
override func viewDidLoad() {
self.scoreLbl.text = userDefaults.integerForKey("CurrentHighScore")
}
不需要同步 iOS 8 及更高版本：
来自 http://www.codingexplorer.com/nsuserdefaults-a-swift-introduction/
Calling synchronize in an iOS 8 app will unnecessarily slow your program, without giving a significant benefit. I’ll let the document speak for itself about the Performance Tradeoffs in NSUserDefaults:
"Reading from NSUserDefaults is extremely fast. It will cache values to avoid reading from the disk, and takes about 0.5 microseconds to do [[NSUserDefaults standardUserDefaults] boolForKey:] on a 2012 MacBook Pro. It’s generally unnecessary (and even undesirable since it prevents picking up new values) to cache the result of reading from preferences.
However, writing to NSUserDefaults is a bit slower. In general, expect it to take roughly as long as using NSPropertyListSerialization to convert your key and value to plist data, plus a few 10s of microseconds. For this reason, as well as memory usage, it’s generally best to store relatively small data in CFPreferences."
你应该把改变乐谱所带来的一切结合到一个方法中。这将使您更容易管理，并使代码更清晰
func saveScore(newScore:Int){
// Set the value of newScore to the class variable score
score = newScore
// Set the value of newScore to the scoreLbl
scoreLbl.text = "\(newScore)"
// Fetch User Defauls
let userDefaults = NSUserDefaults.standardUserDefaults()
// Save newScore value to the userDefaults
userDefaults.setInteger(newScore, forKey: "score")
// Synchronize userDefaults
userDefaults.synchronize()
}
该方法会设置分数，将其放入标签中，同时将分数保存到用户默认值中。只要你想更新分数而不是直接改变分数的值，就调用这个方法。