开发笔记:返回viewcontroller1然后返回viewcontroller2时，UserDefault没有被保存

好的，所以我有两个视图控制器。一个视图控制器加载我的Plist上的所有单元格，第二个视图控制器打开单元格并显示描述。例如：View Controller 1：Dog Cat Mouse

单击Dog cell，它将带您进入View Controller 2：Dog goes Woof。

视图控制器1写道：

ovverride func prepare(for segue: UIStoryBoardSegue, sender: Any?) {
if segue.identifier == "showDetail" {
let animals: Animals
if isFiltering() {
animals = filteredData[indexPath.row]
}
else {
animals = originalData[indexPath.row]
}
let cOntroller= (segue.destination as! UINavigationController).topViewController as! SecondViewController
controller.detailedAnimals = animals
controller.navigationItem.leftBarButtOnItem= splitViewController?.displayModeButtonItem
contrller.navigationItem.leftItemsSupplementBackButton = true
}
}
}


这是我在viewcontroller 2中写的更新

var isFavorite : Bool = false
@IBAction func addToFav(_ sender:UIButton) {
isFavorite = !isFavorite
UpdateButtonAppearance()
saveData()
}
private func UpdateButtonAppearance(){
if isFavorite{
let image = UIImage(named: "addFav")
favButton.setImage(image, for: . normal)
savedData()
}
else {
let image = UIImage(named: "addFavFilled")
favButton.setImage(image, for: . normal)
savedData()
}
}
ovveride func viewDidLoad(){
UpdateButtonAppearance()
saveData()
}
//updated code
func getFilePath () -> String {
var path: [AnyObject] = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true) as [AnyObject]
let documentsDirectory: String = path[0] as! String
let filepath = documentsDirectory.appending("Animals.plist")
return filepath
}
func saveData(){
let myDict : NSMutableDictiOnary= NSMutableDictionary()
myDict["fav"] = NSNumber(booleanLiteral: isFavorite)
myDict.write(toFile: self.getFilePath(), atomically: true)
}
func getBool(){
if FileManager.default.fileExists(atPath: self.getFilePath()) {
var myDict = NSDictionary(contentsOfFile: self.getFilePath()) as!
[String:AnyObject]
let myBool: Bool = myDict["fav"]!.boolValue
isFavorite = myBool
}


我看到了如何在Plist中更改bool并以这种方式编写的教程。代码编译但我认为它不会改变bool值。所以在我的动物Plist上我有一个Item 0类型字典，第一个键叫做Animal，类型是字符串，值是“dog”，第二个键是Description，type是string，value是“dog goes woof”，第三个键被调用fav，类型是Bool，现在值为No但我试图将此值更改为Yes但是它不起作用。也非常感谢你的评论，这很容易理解，也很容易理解。