我的索引路径功能中的cellForRow有问题,我无法遗憾地发现它。所以我转向这个机构的善良人士。 我执行一个获取请求,返回类型为Floors的结果数组(这是我的实体)。我在表中只有一个部分,结果只有一行。如果我声明5层,我只得到一行文本值为" 4"。它总是我声明的价值 - 1.有人可以看看我的代码并帮我发现问题吗?谢谢你,亲切的问候。
class AssignNumberOfRoomsForFloorsVC: UITableViewController {
//MARK: - Properties
private var managedObjectContext: NSManagedObjectContext!
private var storedFloors = [Floors]()
//MARK: - Actions
override func viewDidLoad() {
super.viewDidLoad()
managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
loadFloorData()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
private func loadFloorData() {
let request: NSFetchRequest<Floors> = Floors.fetchRequest()
request.returnsObjectsAsFaults = false
do {
storedFloors = try managedObjectContext.fetch(request)
self.tableView.reloadData()
}
catch {
print("could not load data from core \(error.localizedDescription)")
}
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return storedFloors.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "floor cell", for: indexPath) as! FloorCell
let floorItem = storedFloors[indexPath.row]
cell.floorNumberTxt.text = String(floorItem.floorNumber)
return cell
}
此代码用于设置楼层数:
@IBAction private func setTheNumberOfFloors(_ sender: UIButton) {
let house = NSEntityDescription.insertNewObject(forEntityName: "House", into: managedObjectContext) as! House
house.numberOfFloors = floorNumberValue
print(" the number of floors in the house is: \(house)")
loadFloorData()
for floor in storedFloors {
for i in 0...floor.numberOfFloors - 1 {
let instance = NSEntityDescription.insertNewObject(forEntityName: "Floors", into: managedObjectContext) as! Floors
instance.floorNumber = i
print("\(instance)")
house.addToFloors(instance)
}
}
private func loadFloorData() {
let request = NSFetchRequest<House>(entityName: "House")
request.returnsObjectsAsFaults = false
do {
storedFloors = try managedObjectContext.fetch(request)
}
catch {
print("could not load data from core \(error.localizedDescription)")
}
}
答案 0 :(得分:1)
正如Fahim所说,你需要为用于显示表的fetch设置一个排序描述符:
request.sortDescriptors = [NSSortDescriptor(key: #keyPath(Floors.floorNumber), ascending: true)]
此外,请确保在插入新实体或进行任何修改后保存moc:
do {
try managedObjectContext.save()
} catch {
// Replace this implementation with code to handle the error appropriately.
// fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
}
或者,如果您使用的是标准生成代码:
UIApplication.shared.delegate.saveContext()