Question

我的任务是将此应用的解析调用合并到一个文件中。许多调用都附加了某种UI任务。因此实际调用在文件中，而UI任务仍在其适当的视图控制器中。我遇到的一个问题是一个if let语句，其中一个else提示了一个警告，但if let必须保留在APIManager文件中。所以，基本上if let objects = objects as [PFObject]?必须保持原样，但视图控制器上的最终else语句最初附加到它上面，所以它现在没有任何东西可以用来。

为了澄清，第一个和第二个代码片段只是第三个片段分隔，然后查询放入一个单独的文件中的不同函数，并在函数中添加了一个完成处理程序。执行此操作时，代码的if let objects = objects as [PFObject]?部分必须保留查询，但第二个else语句依赖于它。因为如果没有对象，则显示错误。我正在试图弄清楚如何保持这种功能。

下面是解析调用，然后是视图控制器中随附的代码。我还会在下面加入原始方法。

func viewNeedMetButton(completion: @escaping([PFObject?]) -> Void) {
    let query = PFQuery(className: "Need")
    query.whereKey("committed", equalTo: true)
    query.findObjectsInBackground {(objects: [PFObject]?, error: Error?) in
        if let objects = objects as [PFObject]? {
            completion(objects)
        }
    }
}

视图控制器上与解析调用一起使用的代码。

@IBAction func markAsMet(_ sender: Any) {
    viewNeedMetButton { (objects) in
        if NeedStore.shared.currentNeed?.committed == true {
            for object in objects {
                NeedStore.shared.needObject?.setObject(true, forKey: "met")
                NeedStore.shared.needObject?.saveInBackground() { (success, error) -> Void in
                    if success {
                        let alert = UIAlertController(title: "Success", message: "You have marked this need as met!", preferredStyle: .alert)
                        let OKAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {
                            (_)in
                            self.performSegue(withIdentifier: "unwindToNeedsList", sender: self)
                        })
                        alert.addAction(OKAction)
                        self.present(alert, animated: true, completion: nil)
                    }
                }
            }
        } else {
            let alert = UIAlertController(title: "Error", message: "You cannot declare a need as met if it has not been committed to.", preferredStyle: .alert)
            let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default)
            alert.addAction(okAction)
            self.present(alert, animated: true, completion: {
                return
            })
        } else {
            let alert = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
            let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default)
            alert.addAction(okAction)
            self.present(alert, animated: true, completion: {
                return
            })
        }
    }
}

最后是原始代码，其中所有内容都在同一个函数中。

    @IBAction func markAsMet(_ sender: Any) {
    let query = PFQuery(className: "Need")
    query.whereKey("committed", equalTo: true)
    query.findObjectsInBackground {(objects: [PFObject]?, error: Error?) in
        if let objects = objects as [PFObject]? {
            if NeedStore.shared.currentNeed?.committed == true {
                for object in objects {
                    NeedStore.shared.needObject?.setObject(true, forKey: "met")
                    NeedStore.shared.needObject?.saveInBackground() { (success, error) -> Void in
                        if success {
                            let alert = UIAlertController(title: "Success", message: "You have marked this need as met!", preferredStyle: .alert)
                            let OKAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: {
                                (_)in
                                self.performSegue(withIdentifier: "unwindToNeedsList", sender: self)
                            })
                            alert.addAction(OKAction)
                            self.present(alert, animated: true, completion: nil)
                        }
                    }
                }
            } else {
                let alert = UIAlertController(title: "Error", message: "You cannot declare a need as met if it has not been committed to.", preferredStyle: .alert)
                let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default)
                alert.addAction(okAction)
                self.present(alert, animated: true, completion: {
                    return
                })
            }
        } else {
            let alert = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
            let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default)
            alert.addAction(okAction)
            self.present(alert, animated: true, completion: {
                return
            })
        }
    }
}

我非常感谢您对此提出任何帮助或建议：）

Answer 1

正如其他人在评论中所写：如果其他2不起作用。

我不知道为什么你需要将if移动到另一个功能。但在这里我的解决方案如何让它像以前一样工作

提示：如果你想将一个零件提取到另一个零件，那么你必须在同一级别上切割它：在你的情况下从if NeedStore.shared.currentNeed?.committed == true {直到{{1在if的同一级别上（这是一个级别上的一个块：}）。并且当你将if condition { ... } else { ... }切割的剩余部分切掉时1. Solution

1。溶液

你需要将else部分移动到另一个函数completion(objects)，因为它在错误时被调用。

viewNeedMetButton

视图控制器上与解析调用一起使用的代码。

func viewNeedMetButton(completion: @escaping([PFObject?]) -> Void) {
    let query = PFQuery(className: "Need")
    query.whereKey("committed", equalTo: true)
    query.findObjectsInBackground {(objects: [PFObject]?, error: Error?) in
        if let objects = objects as [PFObject]? {
            completion(objects)
        } else {
            let alert = UIAlertController(title: "Error", message: error?.localizedDescription, preferredStyle: .alert)
            let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default)
            alert.addAction(okAction)
            self.present(alert, animated: true, completion: {
                return
            })
        }
    }
}

2。溶液

如果您希望调用@IBAction func markAsMet(_ sender: Any) { viewNeedMetButton { (objects) in if NeedStore.shared.currentNeed?.committed == true { for object in objects { NeedStore.shared.needObject?.setObject(true, forKey: "met") NeedStore.shared.needObject?.saveInBackground() { (success, error) -> Void in if success { let alert = UIAlertController(title: "Success", message: "You have marked this need as met!", preferredStyle: .alert) let OKAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler: { (_)in self.performSegue(withIdentifier: "unwindToNeedsList", sender: self) }) alert.addAction(OKAction) self.present(alert, animated: true, completion: nil) } } } } else { let alert = UIAlertController(title: "Error", message: "You cannot declare a need as met if it has not been committed to.", preferredStyle: .alert) let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default) alert.addAction(okAction) self.present(alert, animated: true, completion: { return }) } } }更通用，请添加viewNeedMetButton关闭。

onError

视图控制器上与解析调用一起使用的代码。

func viewNeedMetButton(completion: @escaping([PFObject?]) -> Void,
                          onError: @escaping(Error?) -> Void) {
    let query = PFQuery(className: "Need")
    query.whereKey("committed", equalTo: true)
    query.findObjectsInBackground {(objects: [PFObject]?, error: Error?) in
        if let objects = objects as [PFObject]? {
            completion(objects)
        } else {
            onError(error)
        }
    }
}

没有If（解析调用）（编辑）

1 个答案:

1。溶液

2。溶液