Swift，让Code更简洁

• Block语法

public typealias COMPLETE_BLOCK = (AnyObject!, Int32, AnyObject!) -> Void
public typealias PROGRESS_BLOCK = (Int64, Int64) -> Void```

- 使用Block

public func rpcRequestWithURL(url: String!, operationType: String!, requestData: String!, block: COMPLETE_BLOCK!)```

• 使用guard let代替 if else 处理异常情况

guard let videoURLStr = messageModel.param["previewUrl"] as? String,
            title = messageModel.param["strTitle"] as? String,
            desc = messageModel.param["strDesc"] as? String else {return}```

- 用lazy关键字处理不常用的View等控件，比如弹窗，下拉菜单等等

lazy var previewView:XYTemplatePreviewView = {
let view = NSBundle.mainBundle().loadNibNamed("XYTemplatePreviewView", owner: self, options: nil).last as! XYTemplatePreviewView
return view
}()```

• 更灵活的enum（枚举）以及Swith case语句

enum XYBridgedMethod : String {
    case GetLocalThemeList = "getLocalThemeList"
    case DownloadTheme = "downloadTheme"
    case UseTheme = "useTheme"
    case GetLanguage = "getLanguage"
    case ShowThemeVideo = "showThemeVideo"
}

enum XYThemeShopUseThemeType {
    case ApplyTheme
    case CreateNewProject
}```

- 更方便的扩展extension

extension String {
func reverseString() -> String {
// do something if necessary
}
｝ ```

extension UIColor {
    class func clipboardTopBarBGColor() -> UIColor{
        switch colorTheme{
        case .Default:
            return UIColor.color(hex: 0x424242)
        }
    }
}```

- get set方法重写更为简单

var clipSize:CGSize{
get{
let flowLayout = collectionView.collectionViewLayout as! UICollectionViewFlowLayout
return flowLayout.itemSize
}
set{
}
}```

• 使用willSet与didSet来监听值得属性改变

 // 普通属性
    var nickName:String! = ""
    var lastName:String! = ""
    var firstName:String! = ""
    
    // 计算属性
    var fullName:String!{
        get{
            return nickName + "" + lastName + firstName
        }
    }
    
    
    //带属性监视器的普通属性
    var age:Int = 0
        {
        //我们需要在age属性变化前做点什么
        willSet
        {
            print("Will set an new value \(newValue) to age")
        }
        //我们需要在age属性发生变化后，更新一下nickName这个属性
        didSet
        {
            print("age filed changed form \(oldValue) to \(age)")
            if age<10
            {
                nickName = "Little"
            }else
            {
                nickName = "Big"
            }
        }
    }```

- 一句话搞定单例

import Foundation
class SingleOne {
//单例
static let shareSingleOne = SingleOne()
}```

• .#if endif使用

//使用#if DEBUG 需要在Other Swift Flags中，DEBUG下添加-D DEBUG
func printLog<T>(message: T, file: String = #file, method: String = #function, line: Int = #line){
#if DEBUG
    print(logString(message, file: file, method: method, line: line), terminator: "\n")
#endif
}```

- Block弱引用 **unowned**关键字

override func addMoreMethod() {
addMethod(methodName: .GetLocalThemeList) {[unowned self] (messageModel) in
let callbackModel = self.getCallbackModel(messageModel)
let localThemeListDict = self.getLocalThemeList()
let themeListJSON = XYH5ContainerTool.JSONStringWithDic(localThemeListDict)
callbackModel.param = ["themes":themeListJSON]
self.sendMessageToWebWithH5MessageModel(callbackModel)
}
}```

• GCD的简易封装

• 子线程或延迟执行

func async(after second:Double? = nil, block:()->Void){
    if let sec = second {
        dispatch_after(dispatchTimeAfterNow(sec), dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block)
    }else{
        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block)
    }
}```

- 计算时间

func dispatchTime(second:Double)->Int64{
return (Int64)(second * Double(NSEC_PER_SEC))
}

func dispatchTimeAfterNow(second:Double)->dispatch_time_t{
return dispatch_time(DISPATCH_TIME_NOW, dispatchTime(second))
}```

• 主线程或延迟执行

func asyncMain(after second:Double? = nil, block:()->Void){
    if let sec = second {
        dispatch_after(dispatchTimeAfterNow(sec), dispatch_get_main_queue(), block)
    }else{
        dispatch_async(dispatch_get_main_queue(), block)
    }
}```

- 子线程或延时执行

func async(after second:Double? = nil, block:()->Void){
if let sec = second {
dispatch_after(dispatchTimeAfterNow(sec), dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block)
}else{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), block)
}
}```

• 打印log字符串

private func logString<T>(message:T, file:String, method:String, line:Int)->String{
    return "\(printLogDateFormatter.stringFromDate(NSDate())) \((file as NSString).lastPathComponent)[\(line)], \(method): \(message)"
}```