创建一个工具类MTAppHelper

import UIKit

fileprivate let isIphone4 = Int(kScreenH) == 480
fileprivate let isIphone5 = Int(kScreenH) == 568
fileprivate let isIphone6 = Int(kScreenH) == 667
fileprivate let isIphonePlus = Int(kScreenH) == 736

/// 工具类
class MTAppHelper {

/// 根据机型获取指定机型的图片
///
/// - returns: 指定手机类型的图片
static func fetchLaunchImage() -> UIImage? {
    var imageName: String!
    if isIphonePlus {
        imageName = "Default-736h"
    } else if isIphone6 {
        imageName = "Default-667h"
    } else if isIphone5 {
        imageName = "Default-568h@2x~iphone"
    } else {
        imageName = "Default@2x~iphone"
    }
    return UIImage(named: imageName)
}   
}

加载UI时调用方法

showSplashScreenImage();

   /// 闪屏图片视图
lazy var splashImageView: UIImageView = UIImageView(frame: kScreenBounds)


  /// 展示闪屏图片
private func showSplashScreenImage() {
//使用工具类方法        
 splashImageView.image = ZSAppHelper.fetchLaunchImage()
    UIApplication.shared.keyWindow?.addSubview(splashImageView)
}