ios - 为什么在 iOS Swift : unexpectedly found nil while unwrapping an Optional value? 中尝试向服务器发出发布请求时出现此错误

Question

 func uploadImage(var image:UIImage)
{
    var imageData = UIImagePNGRepresentation(image)
    let base64String = imageData!.base64EncodedStringWithOptions([.Encoding64CharacterLineLength]) 
    let parameters = [
        "img": base64String
    ]

    Alamofire.request(.POST, API_URL, parameters:parameters) .response {
        (request, response, data, error) in   
    }    
}

图像不为零。我找不到哪个值实际上为零。

Answer 1

imageData 可能为零。始终不检查并避免展开。

func uploadImage(var image:UIImage) {
  if let imageData = UIImagePNGRepresentation(image), let base64String = imageData.base64EncodedStringWithOptions([.Encoding64CharacterLineLength]) {
    let parameters = [
      "img": base64String
    ]

    Alamofire.request(.POST, API_URL, parameters: parameters) .response {
      (request, response, data, error) in   
    }
  }    
}