大家早上好。我正在使用 Swift 3.1.1、Xcode 8.3.2。我需要通过两个不同的 NSFetchedResultsControllers 将单个 TableView 连接到核心数据中的两个不同表(实体)。我已经创建了两个 NSFetchedResultsControllers，甚至从表中获取数据，但我遇到了如何告诉 TableView 第一个 Controller 应该响应第一部分而第二个 Controller 应该负责第二部分的问题。 我可以给你看代码:
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，所以我在那里提问。我不想在 Core Data 中使用来自单个实体的继承，因为在现实生活中这是不可能的。 感谢您提供任何帮助或建议!
最佳答案
好的 - 我下载了你的代码，但有几个问题......
1) 如果您希望您的数据填充表中的两个部分，则该表必须有两个部分 - 目前，您只返回 1，所以使用这个(尽管您可能希望/需要根据检索到的数据进行不同的处理) :
func numberOfSectionsInTableView(_ tableView: UITableView) -> Int {
if fetchedResultsControllerForModelA == nil || fetchedResultsControllerForModelB == nil {
return 0
}
return 2
}
2) 对于每个部分的行数，您的代码很接近但不太正确...
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，您的代码再次接近，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
}
这应该让你上路。
关于ios - 通过两个不同的带部分的 NSFetchedResultsControllers 的单 TableView ，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44131085/