Question

我有function entity和item，并将值附加到array，但它只添加了最后一项，我认为这是因为每次迭代数组时，我都会将值追加到instance。我无法弄清楚原因。我的功能：

func saveItem(itemToSave: String, key: String){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext

let entity = NSEntityDescription.entity(forEntityName: "Recipe", in: managedContext)
let item = NSManagedObject(entity: entity!, insertInto: managedContext)
item.setValue(itemToSave, forKey: key)
do{
    try managedContext.save()
    recipes.append(item)
}catch{
    print("\(error)")
}}

我如何调用该函数：

if let title = self.newRecipeView.titleTextField.text{
    saveItem(itemToSave: title, key: "title")
}

第一张图片：https://i.stack.imgur.com/UrLbi.png 第二张图片：https://i.stack.imgur.com/XjiEP.png

单击按钮时的操作：

UIView.animate(withDuration: 0.7, delay: 0, options: .curveEaseOut, animations: {
                clearView.alpha = 1
                self.contentView.isUserInteractionEnabled = false
                activityIndicator.startAnimating()
                }, completion: { (true) in

                    if let title = self.newRecipeView.titleTextField.text{
                        saveItem(itemToSave: title, key: "title")
                    }

                    if let category = UserDefaults.standard.object(forKey: "category") as! String?{
                        saveItem(itemToSave: category, key: "category")
                    }

                    if let rating = self.newRecipeView.ratingTextField.text{
                        saveItem(itemToSave: rating, key: "rating")
                    }

                    if let time = self.newRecipeView.timeTextField.text{
                        saveItem(itemToSave: time, key: "time")
                    }

                    if let directions = self.newRecipeView.directionsTextField.text{
                        saveItem(itemToSave: directions, key: "directions")
                    }

                    fetchData()
                    print(recipes)


                    activityIndicator.stopAnimating()
                    _ = self.navigationController?.popToRootViewController(animated: true)
            })

保存数据的方法：

func saveItem(itemToSave: String, key: String){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext

let entity = NSEntityDescription.entity(forEntityName: "Recipe", in: managedContext)
let item = NSManagedObject(entity: entity!, insertInto: managedContext)
item.setValue(itemToSave, forKey: key)
do{
    try managedContext.save()
    recipes.append(item)
}catch{
    print("\(error)")
}

}

获取数据的方法：

func fetchData(){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext

let fetchRequest:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Recipe")
do{
    let results = try managedContext.fetch(fetchRequest)
    recipes = results as! [NSManagedObject]
}catch{
    print("\(error)")
}

}

Answer 1

您的问题是，您为每个Recipe创建了一个新的item。

您需要将功能更改为以下内容：

func saveItem(title: String, rating: String, category: String, time: String, directions: String){
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext

    let entity = NSEntityDescription.entity(forEntityName: "Recipe", in: managedContext)
    let item = NSManagedObject(entity: entity!, insertInto: managedContext)

    recipe.setValue(title, forKey: "title")
    recipe.setValue(rating, forKey: "rating")
    recipe.setValue(category, forKey: "category")
    recipe.setValue(time, forKey: "time")
    recipe.setValue(directions, forKey: "directions")

    do{
        try managedContext.save()
        recipes.append(recipe)
    }catch{
        print("\(error)")
    }
}

然后通过以下方式调用它：

saveItem(title: self.newRecipeView.titleTextField.text, rating: self.newRecipeView.ratingTextField.text, category: (UserDefaults.standard.object(forKey: "category") as! String?), time: self.newRecipeView.timeTextField.text, directions: self.newRecipeView.directionsTextField.text)

核心数据仅保存最后一项

1 个答案: