Swift获取屏幕快照

 // 获取屏幕快照
     private func screenShot() -> UIImage{
         let window = UIApplication.shared.keyWindow!
         UIGraphicsBeginImageContext(window.size)

         // 绘图
         window.drawHierarchy(in: window.bounds, afterScreenUpdates: false)

         // 从图形上下文获取图片
         let image = UIGraphicsGetImageFromCurrentImageContext()!

         UIGraphicsEndImageContext()

         return image
     }