AI代码解释 enumCompassPoint:Int{casesouth=1casenorthcasewestcaseeast// 类型下标 static subscript(index: Int) -> CompassPoint { get { return CompassPoint(rawValue: index)! } }}使用如下:print(CompassPoint[2])// north 类的两段式初始化 Swift中类的初始化是一个两段式过程: 在第一个阶段,每一...
var name: Int? var num: Int? } 优化后 降低内存占用-枚举关联类型的大小取决于最大的关联类型大小 逻辑更清晰- 使用enum相比大量使用if/else逻辑更清晰 enum CustomType { case name(String) case num(Int) } 减少var属性 使用计算属性 使用计算属性可以减少多个变量同步带来的潜在 bug。 不推荐 class model...
通常,我们使用enum枚举来定义各种错误的可能性。 异常处理 假如我们想要读取文件中的内容,在读取的过程中可能会出错。比如当我们调用方法获取结果为nil的时候,我们并不知道到底发生了什么错误而导致没有获取到结果。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 func readFileContent(filePath : String) -...
}enumPlanet{casemercury, venus, earth, mars, jupiter, saturn, uranus, neptune }letsomePlanet=Planet.earthswitchsomePlanet {case.earth:print("Mostly harmless")default:print("Not a safe place for humans") }// 打印“Mostly harmless”// 关联值enumBarcode{case...
enumResult {caseinfo(value: String)casefollowers(value: [String])caseprojects(value: [String]) } func getUser(name: String)async->User {awaitwithTaskGroup(of: Result.self) { groupingroup.addTask { .info(value:awaitgetUserInfo(name)) ...
Note no cases, they aren't needed and add nothing most of the time for examples like this (but see below for exception). The enum is used as a namespace, since enum is the nearest Swift has to a namespace (you will see it used like this in the standard library). ...
typedef NS_ENUM(NSInteger, SwiftMethodKind) {SwiftMethodKindMethod = 0, // methodSwiftMethodKindInit = 1, //initSwiftMethodKindGetter = 2, // getSwiftMethodKindSetter = 3, //setSwiftMethodKindModify = 4, //modifySwiftMethodKindRead = 5, //read}; ...
type. Actual Behavior With var empty = Empty() present, DetailsViewModel initializes and deinitializes twice. However, if the reference type is removed, or when using @StateObject, the behavior is correct (one initialization, one deinitialization). Code Sample import SwiftUI enum Route { case ...
} class SpaceFleet: SpaceThing { enum Formation { // ... } class Spaceship { // ... } var ships: [Spaceship] = [] static let worldName: String = "Earth" func addShip(_ ship: Spaceship) { // ... } } let myFleet = SpaceFleet() Exception: You may prefix a private property...
只读属性:{ get } 使用协议的属性的方法和声明计算属性或存储属性类似,只是后面需要加上关键字。示例: protocol Person2 {var present: Bool { get }var message: String { get set }}struct FullName2: Person2 {var present: Bool = truevar message: String = "名称信息"} ...