保存图片到系统相册（Swift版）

swift 保存图片到系统相册（效果如下）

// 保存到相册    @IBAction func saveToPhoto(sender: AnyObject) {        print("保存到相册")        UIImageWriteToSavedPhotosAlbum(self.myQRCodeImageView.image!, self, "image:didFinishSavingWithError:contextInfo:", nil)    }    // 回调    func image(image: UIImage, didFinishSavingWithError: NSError?, contextInfo: AnyObject) {        if didFinishSavingWithError != nil {            MBProgressHUD.progressHUD(self.view, textMessage: "保存失败,请稍后再试!")            return        }        MBProgressHUD.progressHUD(self.view, textMessage: "已保存在相册")    }