swift -- 适配准备

//公共全局变量
public var DEVICE_TYPE:Int=0 //0为iPhone4s及以下 1为iPhone5s及以下 2为iPhone6 3为iPhone6p及以上
public var DEVICE_WIDTH:CGFloat=0 //设备宽度
public var DEVICE_HIGHT:CGFloat=0 //设备高度
public var FIT_RATE:CGFloat=1 //适配比率

func application(application: UIApplication,didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {  
    let screenRect:CGRect=UIScreen.mainScreen().bounds
    //初始化设备信息
    initDeviceInfo(screenRect)

    return true
}

func initDeviceInfo(deviceRect:CGRect){

        DEVICE_WIDTH=deviceRect.width
        DEVICE_HIGHT=deviceRect.height


        //4s 宽320.0 高480.0
        //5s 宽320.0 高568.0
        //6 宽375.0 高667.0
        //6p 宽414.0 高736.0


        if DEVICE_HIGHT>=736{
            //iPhone6p
            DEVICE_TYPE=3
            FIT_RATE=1.2
        }else if DEVICE_HIGHT>=667 && DEVICE_HIGHT<736{
            //iPhone6
            DEVICE_TYPE=2
            FIT_RATE=1
        }else if DEVICE_HIGHT>=568 && DEVICE_HIGHT<667{
            //iPhone5s
            DEVICE_TYPE=1
            FIT_RATE=1
        }else{
            //iPhone4s
            DEVICE_TYPE=0
            FIT_RATE=0.8
        }

    }

class func getCurrentDeviceDpi()->CGFloat{
        if DEVICE_TYPE==0{
            return 3.78
        }else if DEVICE_TYPE==1{
            return 3.78
        }else if DEVICE_TYPE==2{
            return 3.17
        }else if DEVICE_TYPE==3{
            return 2.78
        }else{
            return 1.31
        }
    }