代碼重複 - swift3

swift3 noob在這裏所以請原諒我，如果這是一個愚蠢的問題。代碼重複 - swift3

我幾次遇到過這個問題，但一直無法解決它。我如何避免下面的代碼重複。

@IBAction func logOutButton(_ sender: Any) { 

    var userEntered = usernameText.text! 

    let appDelegate = UIApplication.shared.delegate as! AppDelegate 
    let context = appDelegate.persistentContainer.viewContext 

    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users") 

    request.predicate = NSPredicate(format: "username = %@", "xyz") 

    do { 

     let results = try context.fetch(request) 

    } catch { 

     print ("Delete failed") 
    } 

} 

@IBAction func submitButton(_ sender: Any) { 
    var users = [String]() 
    var userEntered = usernameText.text! 
    let appDelegate = UIApplication.shared.delegate as! AppDelegate 
    let context = appDelegate.persistentContainer.viewContext 


    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users") 


    let newValue = NSEntityDescription.insertNewObject(forEntityName: "Users", into: context) 

    newValue.setValue(userEntered, forKey: "username") 

    request.returnsObjectsAsFaults = false 

    do { 
     try context.save()

正如你可以看到下面的代碼在兩個按鈕中都重複。我怎樣才能避免這種情況？我試圖用一種方法來編寫它，但我必須做出錯誤的事情，並引發很多錯誤。

var userEntered = usernameText.text! 
    let appDelegate = UIApplication.shared.delegate as! AppDelegate 
    let context = appDelegate.persistentContainer.viewContext 


    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users")

謝謝

來源

2017-04-24 Harj

請出示你試過，你做了什麼錯誤。 – shallowThought

爲什麼不把你正在使用的代碼多次放入一個函數然後調用該函數？ –

使用'NSManagedObject'子類，它避免了很多樣板代碼。然後你可以寫'let request = Users.fetchRequest（）' – vadian

只是要返回一個NSFetchRequest回報功能。

func getFetchRequest() -> NSFetchRequest { 
    let appDelegate = UIApplication.shared.delegate as! AppDelegate 
    let context = appDelegate.persistentContainer.viewContext 
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users") 
    return request 
}

來源

2017-04-24 18:01:10 nighttalker

創建函數返回NSFetchRequest

func getRequest() -> NSFetchRequest { 
    var userEntered = usernameText.text! 
    let appDelegate = UIApplication.shared.delegate as! AppDelegate 
    let context = appDelegate.persistentContainer.viewContext 
    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Users") 
}

那麼你的行爲就會像

@IBAction func logOutButton(_ sender: Any) { 
    let request = getRequest() 
    request.predicate = NSPredicate(format: "username = %@", "xyz") 
    do { 
     let results = try context.fetch(request) 
    } catch { 
     print ("Delete failed") 
    } 
}

來源

2017-07-27 04:07:33

代碼重複 - swift3

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