保存图像以进行解析

Question

我正在处理我的一个应用程序的用户个人资料屏幕。我想让用户 select 来自他 phone 的图像，并能够在应用程序的主屏幕上看到他的个人资料图像。我遇到的问题是保存图像比纯文本需要更长的时间。我想找到一种方法来确保在 segue 将用户带到主屏幕之前保存图像以进行解析。现在只要我点击下一步，segue 就会将用户带到主屏幕。在主屏幕中，无法显示用户的个人资料图片，因为 "saved" 解析的个人资料图片是空的。发生这种情况时，我得到一个零值异常。

注意：当我删除 Segue 时 - 应用程序成功保存了用户信息和用户图像。

以下代码是在我对用户名、密码等进行所有检查之后得到的。

        if photoSelected == false {
        error = "Please select an image to post"
        }

        if error != "" {
        displayAlert("Cannot Post Image", error: error)

        } else {

        var post = PFObject(className: "Images")
        post["username"] = PFUser.currentUser().username

  post.saveInBackgroundWithBlock({ (success: Bool, error: NSError!) -> Void in

        if success == false {
        self.displayAlert("Could not post Image", error: "Please try again later")

        } else {
        let imageData = UIImagePNGRepresentation(self.profileImage.image)
        let profilePic = PFFile(name: "image.png", data: imageData)

        post["profileImage"] = profilePic;

            //I even added an activity indicator to stall the app before proceeding to the main page. 
            activityIndicator = UIActivityIndicatorView(frame: CGRectMake(0, 0, 200, 200))
            activityIndicator.center = self.view.center
            activityIndicator.hidesWhenStopped = true
            activityIndicator.activityIndicatorViewStyle = UIActivityIndicatorViewStyle.WhiteLarge
            self.view.addSubview(activityIndicator)
            activityIndicator.startAnimating()
            UIApplication.sharedApplication().beginIgnoringInteractionEvents()


        post.saveInBackgroundWithBlock({ (success: Bool, error: NSError!) -> Void in


            UIApplication.sharedApplication().endIgnoringInteractionEvents()

        if success == false {
        self.displayAlert("Could not post Image", error: "Please try again later")
        } else {
         //check    
        println("picture was uploaded")

        }
        })

       }
    })
  }


        //saves all the user's values username, password, etc. 
        self.user.save()

     //takes the user to the MainScreen     
    self.performSegueWithIdentifier("moveToMainScreen", sender: self)

    }

非常感谢您的帮助！

Answer 1

移动这些行：

 //takes the user to the MainScreen     
self.performSegueWithIdentifier("moveToMainScreen", sender: self)

更高处，进入图像保存的完成块（您现在有 println("picture was uploaded")。

保存图像以进行解析

Saving Image to Parse

save-image

ios

parse-platform

swift