选择器视图中来自核心数据的数据

Question

我正在为一个学校项目开发一个应用程序。该应用程序应管理不同的客户（使用客户名称和电子邮件地址）和任务（使用任务名称和每小时价格）。 那么应用程序应该根据这些数据创建一个账单。

我的问题是如何在两个选择器视图中从客户和任务（存储在核心数据中）获取数据？

完整项目的链接：https://drive.google.com/open?id=0Bwwqhrg9CBVfTU50R2dBaF9ZcUk

（抱歉使用德语变量和函数名：/）

这是任务的资源

//
//  ArrayAufgabenResource.swift
//  TheServiceAppV2
//
//  Created by David Zerweck on 09.04.17.
//  Copyright © 2017 David Zerweck. All rights reserved.
//

////////////////////////////////////////////////////
    //German = English

    //Kunde = Customer
    //Aufgabe = Task
////////////////////////////////////////////////////
import Foundation
import CoreData

struct ArrayAufgabeResource: AufgabeResource {

var persistentContainer: NSPersistentContainer = {

    let container = NSPersistentContainer(name: "TheServiceAppV2")
    container.loadPersistentStores {
        (storeDescription, error) in

        if let error = error {
            let nserror = error as NSError
            fatalError("Fehler: \(nserror.localizedDescription)")
        }
    }
    return container
}()

func saveContext() {
    let context = persistentContainer.viewContext
    if context.hasChanges {
        do {
            try context.save()
        } catch {
            let nserror = error as NSError
            fatalError("Fehler: \(nserror.localizedDescription)")
        }
    }
}

func insertAufgabe(withName: String, andPreis: String) -> Aufgabe {
    let newAufgabe = NSEntityDescription.insertNewObject(forEntityName: "Aufgabe", into: persistentContainer.viewContext) as! Aufgabe

    newAufgabe.nameDerAufgabe = withName
    newAufgabe.preisProStunde = andPreis

    saveContext()
    return newAufgabe
}

func remove(aufgabe: Aufgabe) {
    persistentContainer.viewContext.delete(aufgabe)
    saveContext()
}

func getList() -> [Aufgabe] {
    var aufgaben = [Aufgabe]()

    let request: NSFetchRequest<Aufgabe> = Aufgabe.fetchRequest()
    do {
        aufgaben = try persistentContainer.viewContext.fetch(request)
    } catch {
        print(error.localizedDescription)
    }

    return aufgaben
}   
}

这是客户资源

//
//  ArrayKundenResource.swift
//  TheServiceAppV2
//
//  Created by David Zerweck on 09.04.17.
//  Copyright © 2017 David Zerweck. All rights reserved.
//

import Foundation
import CoreData

struct ArrayKundeResource: KundeResource {

var persistentContainer: NSPersistentContainer = {

    let container = NSPersistentContainer(name: "TheServiceAppV2")
    container.loadPersistentStores {
        (storeDescription, error) in

        if let error = error {
            let nserror = error as NSError
            fatalError("Fehler: \(nserror.localizedDescription)")
        }
    }

    return container
}()

func saveContext() {
    let context = persistentContainer.viewContext
    if context.hasChanges {
        do {
            try context.save()
        } catch {
            let nserror = error as NSError
            fatalError("Fehler: \(nserror.localizedDescription)")
        }
    }
}

func insertKunde(withName: String, andEmail: String) -> Kunde {

    let newKunde = NSEntityDescription.insertNewObject(forEntityName: "Kunde", into: persistentContainer.viewContext) as! Kunde

    newKunde.name = withName
    newKunde.email = andEmail

    saveContext()

    return newKunde
}

func remove(kunde: Kunde) {
    persistentContainer.viewContext.delete(kunde)
    saveContext()
}


func getList() -> [Kunde] {
    var kunden = [Kunde]()

    let request: NSFetchRequest<Kunde> = Kunde.fetchRequest()
    do {
        kunden = try persistentContainer.viewContext.fetch(request)
    } catch {
        print(error.localizedDescription)
    }

    return kunden
 }
}  

在下面的 ViewController 中，应该有两个选择器视图。第一个选择器视图应该显示客户。第二个选择器视图应该显示任务。

//
//  RechnungViewController.swift
//  TheServiceAppV2
//
//  Created by David Zerweck on 17.05.17.
//  Copyright © 2017 David Zerweck. All rights reserved.
//

////////////////////////////////////////////////////
//German = English

//Kunde = Customer
//Aufgabe = Task
//Rechnung = Bill
////////////////////////////////////////////////////

import UIKit

class RechnungViewController: UIViewController {


@IBOutlet weak var pickerViewKunde: UIPickerView!

@IBOutlet weak var pickerViewAufgabe: UIPickerView!

@IBOutlet weak var anzahlStundenField: UITextField! //number of hours


@IBAction func rechnungBtn(_ sender: Any) {
}


override func viewDidLoad() {
    super.viewDidLoad()

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
 }
}

我希望有人可以帮助我。 我已经在说谢谢你的帮助。

Answer 1

你可以得到如下代码的数据：

这是您的控制器，只需复制粘贴即可使用。

import UIKit

class RechnungViewController: UIViewController , UIPickerViewDelegate, UIPickerViewDataSource {


@IBOutlet weak var pickerViewKunde: UIPickerView!

@IBOutlet weak var pickerViewAufgabe: UIPickerView!

@IBOutlet weak var anzahlStundenField: UITextField!


var allKunden = [Kunde]()

@IBAction func rechnungBtn(_ sender: Any) {
}


override func viewDidLoad() {
    super.viewDidLoad()

    //Temp Add data
    var kun = Kunde()
    let arr : ArrayKundeResource = ArrayKundeResource()
    kun = arr.insertKunde(withName: "JIGAR", andEmail: "jigar@mail.com")
    print(kun.email)
    print(kun.name)
 //This is for temporary adding data inside coredata so you can remove this.

    //get all customer
    self.getAllCustomer()
}

func getAllCustomer() {

    let arr : ArrayKundeResource = ArrayKundeResource()
    self.allKunden = arr.getList()

    print(self.allKunden.count)
}

//pickerview datasource methods
func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return self.allKunden.count
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    let kundObj = self.allKunden[row] as Kunde
    return kundObj.name
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    let kundObj = self.allKunden[row] as Kunde
    print(kundObj.name)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

}