Ios 通过两个具有节的不同NSFetchedResultsController查看单个表

大家早上好。我使用的是Swift 3.1.1，Xcode 8.3.2。我需要通过两个不同的NSFetchedResultsController将单个表视图连接到核心数据中的两个不同表（实体）。我创建了两个NSFetchedResultsController，甚至从表中提取了数据，但我面临的问题是如何告诉表视图第一个控制器应该响应第一节，第二个控制器应该负责第二节。 我可以向您展示代码：

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var tv: UITableView!

    @IBAction func pressed(_ sender: UIButton) {
        ModelA.read { table1 in
            ModelB.read { table2 in
                if table1.isEmpty {
                    ModelA.save(recordToSave: [(a: 1, b: "a"), (a: 2, b: "b"), (a: 3, b: "c")]) {
                        ModelB.save(recordToSave: [(a: 4, b: 5.0, c: true), (a: 6, b: 7.0, c: false)]) {
                            self.tvReload()
                        }
                    }
                } else {
                    self.tvReload()
                }
            }
        }
    }

    var fetchedResultsControllerForModelA = CoreDataFunctions.fetchedResultsController
    var fetchedResultsControllerForModelB = CoreDataFunctions.fetchedResultsController

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        tvReload()
    }

    func modelOfTableA(indexPath: IndexPath) -> (forLabel1: String, forLabel2: String, forLabel3: String)? {
        if let fetchedResultsControllerForModelA = CoreDataFunctions.getNSManagedObjectForIndexPathOfTable(fetchedResultsController: fetchedResultsControllerForModelA, indexPath: indexPath) {
            if let model = ModelA.read(nsmanagedobject: fetchedResultsControllerForModelA) {
                return (forLabel1: "\(model.a)", forLabel2: model.b, forLabel3: "")
            }
        }
        return nil
    }

    func modelOfTableB(indexPath: IndexPath) -> (forLabel1: String, forLabel2: String, forLabel3: String)? {
        if let fetchedResultsControllerForModelB = CoreDataFunctions.getNSManagedObjectForIndexPathOfTable(fetchedResultsController: fetchedResultsControllerForModelB, indexPath: indexPath) {
            if let model = ModelB.read(nsmanagedobject: fetchedResultsControllerForModelB) {
                return (forLabel1: "\(model.a)", forLabel2: "\(model.b)", forLabel3: "\(model.c)")
            }
        }
        return nil
    }

    func tvReload() {
        fetchedResultsControllerForModelA = CoreDataFunctions(tableName: .a).fetchedResultsController(keyForSort: ModelA.a.rawValue, searchParameters: nil)
        fetchedResultsControllerForModelB = CoreDataFunctions(tableName: .b).fetchedResultsController(keyForSort: ModelB.a.rawValue, searchParameters: nil)

        do {
            try fetchedResultsControllerForModelA?.performFetch()
            try fetchedResultsControllerForModelB?.performFetch()

            DispatchQueue.main.async {
                self.tv.reloadData()
            }
        } catch {
            print("Error")
        }
    }

    func numberOfSectionsInTableView(_ tableView: UITableView) -> Int {
        return 1
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if let sections1 = fetchedResultsControllerForModelA?.sections {
            if let sections2 = fetchedResultsControllerForModelB?.sections {
                return sections1[section].numberOfObjects + sections2[section].numberOfObjects
            }
            return sections1[section].numberOfObjects
        }
        return 0
    }

    func tableView(_ tableView: UITableView, cellForRowAtIndexPath indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell

        if indexPath.section == 0 {
            if let modelOfTable = modelOfTableA(indexPath: indexPath) {
                cell.l1.text = modelOfTable.forLabel1
                cell.l2.text = modelOfTable.forLabel2
                cell.l3.text = modelOfTable.forLabel3
            }
        } else {
            if let modelOfTable = modelOfTableB(indexPath: indexPath) {
                cell.l1.text = modelOfTable.forLabel1
                cell.l2.text = modelOfTable.forLabel2
                cell.l3.text = modelOfTable.forLabel3
            }
        }

        return cell
    }

}

我找不到关于这个主题的任何教程，所以我在那里问了一个问题。我不想在核心数据中使用单个实体的继承，因为在现实生活中这是不可能的。

---

谢谢你的帮助和建议

好的-我下载了你的代码，有几个问题

1） 如果希望数据填充表中的两个部分，则该表必须有两个部分-当前，您仅返回1，因此请使用此选项（尽管您可能希望/需要根据检索到的数据进行不同的处理）：

2） 对于每个部分中的行数，您的代码很接近，但不完全正确

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    if section == 0 {
        if let sections = fetchedResultsControllerForModelA?.sections {
            return sections[0].numberOfObjects
        }
    } else {
        if let sections = fetchedResultsControllerForModelB?.sections {
            return sections[0].numberOfObjects
        }
    }

    return 0

}

3） 对于实际的cellForRowAtIndexPath数据，您的代码也很接近，但您需要跟踪每个部分要获取的数据

func tableView(_ tableView: UITableView, cellForRowAtIndexPath indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell

    if indexPath.section == 0 {
        if let modelOfTable = modelOfTableA(indexPath: indexPath) {
            cell.l1.text = modelOfTable.forLabel1
            cell.l2.text = modelOfTable.forLabel2
            cell.l3.text = modelOfTable.forLabel3
        }
    } else {
        // Each "Table data model" has only one section... since this is the 2nd table section, we need
        //  to change the section of the index path for our call to the data model
        let dataIndexPath = IndexPath(row: indexPath.row, section: 0)
        if let modelOfTable = modelOfTableB(indexPath: dataIndexPath) {
            cell.l1.text = modelOfTable.forLabel1
            cell.l2.text = modelOfTable.forLabel2
            cell.l3.text = modelOfTable.forLabel3
        }
    }

    return cell
}

---

这应该会让您走上正轨。

为什么您不是每个部分的单独数组？即使没有NSFetchedResultsController，我也可以为两个部分使用单个元组数组。我认为这是不对的，但是，你能解释一下这部分吗？让dataIndexPath=IndexPath（row:IndexPath.row，section:0）有两个数据模型——每个表节一个。但每个数据模型只有一个数据部分。因此，如果您调用

modelOfTableB（）

并在第二节中传递表的第一行索引路径，您将询问“第1节，第0行”。。。这将失败，因为“第1节”是第二节（基于零的索引）。好的，我想我现在明白了！再次感谢你！

func tableView(_ tableView: UITableView, cellForRowAtIndexPath indexPath: IndexPath) -> UITableViewCell {

    let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableViewCell

    if indexPath.section == 0 {
        if let modelOfTable = modelOfTableA(indexPath: indexPath) {
            cell.l1.text = modelOfTable.forLabel1
            cell.l2.text = modelOfTable.forLabel2
            cell.l3.text = modelOfTable.forLabel3
        }
    } else {
        // Each "Table data model" has only one section... since this is the 2nd table section, we need
        //  to change the section of the index path for our call to the data model
        let dataIndexPath = IndexPath(row: indexPath.row, section: 0)
        if let modelOfTable = modelOfTableB(indexPath: dataIndexPath) {
            cell.l1.text = modelOfTable.forLabel1
            cell.l2.text = modelOfTable.forLabel2
            cell.l3.text = modelOfTable.forLabel3
        }
    }

    return cell
}