nsuserdefaults

来源： https://stackoverflow.com/questions/62602279/using-appstorage-for-string-map

问题 This is the exact error I get: valueNotFound(Foundation.Data, Swift.DecodingError.Context(codingPath: [_PlistKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "wishData", intValue: nil), _PlistKey(stringValue: "Index 0", intValue: 0), CodingKeys(stringValue: "image", intValue: nil)], debugDescription: "Expected Data value but found null instead.", underlyingError: nil)) Details: I have two custom strcuts : Wishlist : struct Wishlist: Codable { var name: String var image:

问题 I'm trying to store a dictionary in UserDefaults and always get app crash when the code runs. Here is the sample code which crashes the app when it is executed. I tried to cast it as NSDictionary or make it NSDictionary initially - got the same result. class CourseVC: UIViewController { let test = [1:"me"] override func viewDidLoad() { super.viewDidLoad() defaults.set(test, forKey: "dict1") } } 回答1: Dictionaries are Codable objects by default, you can use the following extensions to save them

问题 Are operations on UserDefaults synchronous? For example does the second save wait for the first save to finish? UserDefaults.standard.set(myValue1, forKey: "myValue1") UserDefaults.standard.set(myValue2, forKey: "myValue2") 回答1: From apple's documentation: At runtime, you use UserDefaults objects to read the defaults that your app uses from a user’s defaults database. UserDefaults caches the information to avoid having to open the user’s defaults database each time you need a default value.

问题 Are operations on UserDefaults synchronous? For example does the second save wait for the first save to finish? UserDefaults.standard.set(myValue1, forKey: "myValue1") UserDefaults.standard.set(myValue2, forKey: "myValue2") 回答1: From apple's documentation: At runtime, you use UserDefaults objects to read the defaults that your app uses from a user’s defaults database. UserDefaults caches the information to avoid having to open the user’s defaults database each time you need a default value.

问题 By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. So, does this protocol (known as PropertyListObject in the code below) exist, or do we need to make our own? If we do need to make our own, has someone made a definitive one? public protocol UserDefaults_Value_WrappedValue { associatedtype PropertyListObject: HM.PropertyListObject init?(propertyListObject: Any) var convertertedToPropertyListObject: PropertyListObject { get } } public

问题 By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. So, does this protocol (known as PropertyListObject in the code below) exist, or do we need to make our own? If we do need to make our own, has someone made a definitive one? public protocol UserDefaults_Value_WrappedValue { associatedtype PropertyListObject: HM.PropertyListObject init?(propertyListObject: Any) var convertertedToPropertyListObject: PropertyListObject { get } } public

问题 By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. So, does this protocol (known as PropertyListObject in the code below) exist, or do we need to make our own? If we do need to make our own, has someone made a definitive one? public protocol UserDefaults_Value_WrappedValue { associatedtype PropertyListObject: HM.PropertyListObject init?(propertyListObject: Any) var convertertedToPropertyListObject: PropertyListObject { get } } public

问题 By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. So, does this protocol (known as PropertyListObject in the code below) exist, or do we need to make our own? If we do need to make our own, has someone made a definitive one? public protocol UserDefaults_Value_WrappedValue { associatedtype PropertyListObject: HM.PropertyListObject init?(propertyListObject: Any) var convertertedToPropertyListObject: PropertyListObject { get } } public

问题 By convention, each Cocoa and Core Foundation object listed in Table 2-1 is called a property-list object. So, does this protocol (known as PropertyListObject in the code below) exist, or do we need to make our own? If we do need to make our own, has someone made a definitive one? public protocol UserDefaults_Value_WrappedValue { associatedtype PropertyListObject: HM.PropertyListObject init?(propertyListObject: Any) var convertertedToPropertyListObject: PropertyListObject { get } } public