diff --git a/source/chapter2/11_Methods.md b/source/chapter2/11_Methods.md index b4c76fb4..6bfcab74 100755 --- a/source/chapter2/11_Methods.md +++ b/source/chapter2/11_Methods.md @@ -9,10 +9,10 @@ > 翻译+校对:[DianQK](https://github.com/DianQK) > 2.1 -> 翻译:[DianQK](https://github.com/DianQK),[Realank](https://github.com/Realank) 校对:[shanks](http://codebuild.me),2016-01-18 -> -> 2.2 -> 校对:[SketchK](https://github.com/SketchK) 2016-05-13 +> 翻译:[DianQK](https://github.com/DianQK),[Realank](https://github.com/Realank) 校对:[shanks](http://codebuild.me),2016-01-18 +> +> 2.2 +> 校对:[SketchK](https://github.com/SketchK) 2016-05-13 > 3.0.1,shanks,2016-11-13 本页包含内容: @@ -34,17 +34,17 @@ 下面的例子,定义一个很简单的`Counter`类,`Counter`能被用来对一个动作发生的次数进行计数: ```swift -class Counter { - var count = 0 - func increment() { - count += 1 - } - func increment(by amount: Int) { - count += amount - } - func reset() { - count = 0 - } +class Counter { + var count = 0 + func increment() { + count += 1 + } + func increment(by amount: Int) { + count += amount + } + func reset() { + count = 0 + } } ``` @@ -62,15 +62,15 @@ let counter = Counter() // 初始计数值是0 counter.increment() // 计数值现在是1 -counter.increment(by: 5) +counter.increment(by: 5) // 计数值现在是6 counter.reset() // 计数值现在是0 ``` -函数参数可以同时有一个局部名称(在函数体内部使用)和一个外部名称(在调用函数时使用),详情参见[指定外部参数名](./06_Functions.html#specifying_external_parameter_names)。方法参数也一样,因为方法就是函数,只是这个函数与某个类型相关联了。 - - +函数参数可以同时有一个局部名称(在函数体内部使用)和一个外部名称(在调用函数时使用),详情参见[指定外部参数名](./06_Functions.html#specifying_external_parameter_names)。方法参数也一样,因为方法就是函数,只是这个函数与某个类型相关联了。 + + ### self 属性 @@ -104,8 +104,8 @@ if somePoint.isToTheRightOfX(1.0) { // 打印 "This point is to the right of the line where x == 1.0" ``` -如果不使用`self`前缀,Swift 就认为两次使用的`x`都指的是名称为`x`的函数参数。 - +如果不使用`self`前缀,Swift 就认为两次使用的`x`都指的是名称为`x`的函数参数。 + ### 在实例方法中修改值类型 @@ -137,19 +137,19 @@ print("The point is now at (\(somePoint.x), \(somePoint.y))") let fixedPoint = Point(x: 3.0, y: 3.0) fixedPoint.moveByX(2.0, y: 3.0) // 这里将会报告一个错误 -``` - +``` + ### 在可变方法中给 self 赋值 可变方法能够赋给隐含属性`self`一个全新的实例。上面`Point`的例子可以用下面的方式改写: ```swift -struct Point { - var x = 0.0, y = 0.0 - mutating func moveBy(x deltaX: Double, y deltaY: Double) { - self = Point(x: x + deltaX, y: y + deltaY) - } +struct Point { + var x = 0.0, y = 0.0 + mutating func moveBy(x deltaX: Double, y deltaY: Double) { + self = Point(x: x + deltaX, y: y + deltaY) + } } ``` @@ -162,12 +162,12 @@ enum TriStateSwitch { case Off, Low, High mutating func next() { switch self { - case Off: - self = Low - case Low: - self = High - case High: - self = Off + case .Off: + self = .Low + case .Low: + self = .High + case .High: + self = .Off } } } @@ -208,27 +208,27 @@ SomeClass.someTypeMethod() 游戏初始时,所有的游戏等级(除了等级 1)都被锁定。每次有玩家完成一个等级,这个等级就对这个设备上的所有玩家解锁。`LevelTracker`结构体用类型属性和方法监测游戏的哪个等级已经被解锁。它还监测每个玩家的当前等级。 ```swift -struct LevelTracker { - static var highestUnlockedLevel = 1 - var currentLevel = 1 - - static func unlock(_ level: Int) { - if level > highestUnlockedLevel { highestUnlockedLevel = level } - } - - static func isUnlocked(_ level: Int) -> Bool { - return level <= highestUnlockedLevel - } - - @discardableResult - mutating func advance(to level: Int) -> Bool { - if LevelTracker.isUnlocked(level) { - currentLevel = level - return true - } else { - return false - } - } +struct LevelTracker { + static var highestUnlockedLevel = 1 + var currentLevel = 1 + + static func unlock(_ level: Int) { + if level > highestUnlockedLevel { highestUnlockedLevel = level } + } + + static func isUnlocked(_ level: Int) -> Bool { + return level <= highestUnlockedLevel + } + + @discardableResult + mutating func advance(to level: Int) -> Bool { + if LevelTracker.isUnlocked(level) { + currentLevel = level + return true + } else { + return false + } + } } ``` @@ -243,16 +243,16 @@ struct LevelTracker { 下面,`Player`类使用`LevelTracker`来监测和更新每个玩家的发展进度: ```swift -class Player { - var tracker = LevelTracker() - let playerName: String - func complete(level: Int) { - LevelTracker.unlock(level + 1) - tracker.advance(to: level + 1) - } - init(name: String) { - playerName = name - } +class Player { + var tracker = LevelTracker() + let playerName: String + func complete(level: Int) { + LevelTracker.unlock(level + 1) + tracker.advance(to: level + 1) + } + init(name: String) { + playerName = name + } } ``` @@ -261,8 +261,8 @@ class Player { 你还可以为一个新的玩家创建一个`Player`的实例,然后看这个玩家完成等级一时发生了什么: ```swift -var player = Player(name: "Argyrios") -player.complete(level: 1) +var player = Player(name: "Argyrios") +player.complete(level: 1) print("highest unlocked level is now \(LevelTracker.highestUnlockedLevel)") // 打印 "highest unlocked level is now 2" ``` @@ -270,11 +270,11 @@ print("highest unlocked level is now \(LevelTracker.highestUnlockedLevel)") 如果你创建了第二个玩家,并尝试让他开始一个没有被任何玩家解锁的等级,那么试图设置玩家当前等级将会失败: ```swift -player = Player(name: "Beto") -if player.tracker.advance(to: 6) { - print("player is now on level 6") -} else { - print("level 6 has not yet been unlocked") +player = Player(name: "Beto") +if player.tracker.advance(to: 6) { + print("player is now on level 6") +} else { + print("level 6 has not yet been unlocked") } // 打印 "level 6 has not yet been unlocked" ```