Ios 用CoreData存储

我的应用程序非常简单：我有一个tableview来存储配方*名称，对于每个配方名称，还有一个tableview，其中包含每个配方的若干*成分

我已经用CoreData保存了名称和配料，但问题是：当我按下添加新配方名称并进入配料表视图区域时，为上一个配方保存的配料就在那里！如何清除表格视图以启动新的表格视图

此外，我的表视图不会立即更新，我必须关闭应用程序并再次打开它。我怎么修理它

注意：如果我的问题太难理解，我可以发布一些代码！提前谢谢大家=）

编辑

代码：

-

-

-

和型号：

import Foundation
import CoreData

class Ingredients: NSManagedObject {

    @NSManaged var ingredients: String
    @NSManaged var relationship: NSSet

} 概述：

您需要修改您的模型：当前每个

详细信息

对象只能有一个

成分

。我怀疑你需要这种“对多”的关系，这样一份食谱就可以有很多成分

您需要将变量（类型为

Details？

）添加到您的

InCreditListViewController

。这将代表所选的配方。（例如，

var chosenRecipe:详细信息？

）

在

fetchComponent

中，您需要向fetch添加一个谓词，以将结果限制到所选配方。例如，

fetch.predicate=NSPredicate（格式：“任意关系==%@”，chosenRecipe）

在切换到此VC之前，您需要设置

chosenRecipe

（可能在prepareForSegue中，或者在前面的表视图中设置DidSelectRowatineXpath）

要使电视自动更新，请使用

fetchedResultsController

delegate方法。（你实施了这些吗？）

---

我设法使我的TableView工作，但我仍然不知道如何清除列表，因为当我添加新项目时，旧项目将不会显示。我做完后会告诉你的！我不知道如何设置CoreData以在启动新项目时清除所有数据：（你能教我吗？@NicholasPiccoli你能再解释一下剩余问题吗？想象一下：我有一个包含多个项目的tableview，每个项目都有它自己的tableview和它自己的项目。例如，当我添加第一个配方并添加它的配料时，一切都正常，但当我输入第二个配方并尝试添加它的新配料时成分，预览配方的成分在那里！等等。它们会累积。我希望了解如何在每次添加新配方时清除成分表视图。注意：我必须重置它，但将其保留在内存中，因为稍后当我通过DidseleCrowatineXpath访问添加的每个配方的行时，将显示一个屏幕，其中包含e的详细信息每一份食谱。

import UIKit
import CoreData

class InfoViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate, UITableViewDelegate {


    @IBOutlet var nameField: UITextField!
    @IBOutlet var imageView: UIImageView!
    var moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

    override func viewDidLoad() {
        super.viewDidLoad()

        //Pick the image by tap
        let tapGestureRecognizer: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "chooseImage:")
        tapGestureRecognizer.numberOfTapsRequired = 1
        imageView.addGestureRecognizer(tapGestureRecognizer)
        imageView.userInteractionEnabled = true

    }

    //Pick the image by tapping, accessing the photoLibrary
    func chooseImage(recognizer: UITapGestureRecognizer) {
        let imagePicker: UIImagePickerController = UIImagePickerController()
        imagePicker.delegate = self
        imagePicker.sourceType = UIImagePickerControllerSourceType.PhotoLibrary
        self.presentViewController(imagePicker, animated: true, completion: nil)
    }

    //Put the selected image into the screen
    func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [NSObject:AnyObject]) {
        let pickedImage: UIImage = (info as NSDictionary).objectForKey(UIImagePickerControllerOriginalImage) as! UIImage
        // small picture
        let smallPicture = scaleImageWith(pickedImage, newSize: CGSizeMake(288,148))
        var sizeOfImageView:CGRect = imageView.frame
        sizeOfImageView.size = smallPicture.size
        imageView.frame = sizeOfImageView
        imageView.image = smallPicture
        picker.dismissViewControllerAnimated(true, completion: nil)
    }


    func imagePickerControllerDidCancel(picker: UIImagePickerController) {
        picker.dismissViewControllerAnimated(true, completion: nil)
    }

    func scaleImageWith(image:UIImage, newSize: CGSize) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(newSize, false, 0.0)
        image.drawInRect(CGRectMake(0,0, newSize.width, newSize.height))
        let newImage: UIImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }

    @IBAction func addButton(sender: AnyObject) {

        let entityDescription = NSEntityDescription.entityForName("Details", inManagedObjectContext: moc!)
        let details = Details(entity: entityDescription!, insertIntoManagedObjectContext: moc)
        details.name = nameField.text

        var error: NSError?
        moc?.save(&error)

        if let err = error {
            var status = err.localizedFailureReason
            println("\(status)")
        } else {
            println("Ingredient \(nameField.text) saved successfully!")
        }
            if let navigation = navigationController {
            navigation.popViewControllerAnimated(true)

        }
    }
}

import UIKit
import CoreData

class IngredientListViewController: UIViewController, NSFetchedResultsControllerDelegate {

    @IBOutlet var tableView: UITableView!
    var moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
    var fetchedResultsController: NSFetchedResultsController?

    override func viewDidLoad() {
        super.viewDidLoad()
        fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchIngredient(), managedObjectContext: moc!, sectionNameKeyPath: nil, cacheName: nil)
        fetchedResultsController?.delegate = self
        fetchedResultsController?.performFetch(nil)
        tableView.reloadData()
    }

    func fetchIngredient() -> NSFetchRequest {
        var fetchRequest = NSFetchRequest(entityName: "Ingredients")
        let sortDescriptor = NSSortDescriptor(key: "ingredients", ascending: true)
        fetchRequest.predicate = nil
        fetchRequest.sortDescriptors = [sortDescriptor]
        fetchRequest.fetchBatchSize = 20
        return fetchRequest
    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return fetchedResultsController?.sections?[section].numberOfObjects ?? 0
    }

    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("ingCell", forIndexPath: indexPath) as! UITableViewCell
        if let recipeCell = fetchedResultsController?.objectAtIndexPath(indexPath) as? Ingredients {
            cell.textLabel?.text = recipeCell.ingredients
        }
        return cell
    }
}

import UIKit
import CoreData

class IngredientViewController: UIViewController {


    @IBOutlet var nameField: UITextField!
    var moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext



    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    @IBAction func addButton(sender: AnyObject) {

        let entityDescription = NSEntityDescription.entityForName("Ingredients", inManagedObjectContext: moc!)
        let details = Ingredients(entity: entityDescription!, insertIntoManagedObjectContext: moc)
        details.ingredients = nameField.text

        var error: NSError?
        moc?.save(&error)

        if let err = error {
            var status = err.localizedFailureReason
            println("\(status)")
        } else {
            println("Ingredient \(nameField.text) saved successfully!")
        }
        if let navigation = navigationController {
            navigation.popViewControllerAnimated(true)

        }
    }
}

import Foundation
import CoreData

class Ingredients: NSManagedObject {

    @NSManaged var ingredients: String
    @NSManaged var relationship: NSSet

import Foundation
import CoreData

class Details: NSManagedObject {

    @NSManaged var name: String
    @NSManaged var relationship: Ingredients

}