我走了一條不同的路線。繼承人我想做什麼。設計我的應用程序,讓我保存核心數據並在tableview中的另一個控制檯中查看它。一旦進入tableview控制檯,我也可以在控制檯的頂部看到一個圖表。
我做了什麼:
我創建了一個UIViewController,拖過一個imageview的只是使用它作爲一個例子。我也拖入桌面視圖,單元格等等。
我的問題:
我可以查看空白的tableview細胞和看到樣品圖像。一旦我保存核心數據並返回來嘗試查看數據,就會出現錯誤。我有數據源和委託實現,但是,我需要把它放在我的代碼中。
class ViewMealsViewController: UIViewController, NSFetchedResultsControllerDelegate {
@IBOutlet weak var tableView: UITableView!
@IBOutlet weak var menuButton: UIBarButtonItem!
let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext
var fetchedResultController: NSFetchedResultsController<MealStats> = NSFetchedResultsController()
override func viewDidLoad() {
super.viewDidLoad()
fetchedResultController = getFetchedResultController()
fetchedResultController.delegate = self
do {
try fetchedResultController.performFetch()
} catch _ {
}
if revealViewController() != nil {
revealViewController().rearViewRevealWidth = 325
menuButton.target = revealViewController()
menuButton.action = #selector(SWRevealViewController.revealToggle(_:))
view.addGestureRecognizer(self.revealViewController().panGestureRecognizer())
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK:- Retrieve Stats
func getFetchedResultController() -> NSFetchedResultsController<MealStats> {
fetchedResultController = NSFetchedResultsController(fetchRequest: taskFetchRequest(), managedObjectContext: managedObjectContext, sectionNameKeyPath: nil, cacheName: nil)
return fetchedResultController
}
func taskFetchRequest() -> NSFetchRequest<MealStats> {
let fetchRequest = NSFetchRequest<MealStats> (entityName: "MealStats")
let timeSortDescriptor = NSSortDescriptor(key: "mealtype",
ascending: true, selector: #selector(NSString.caseInsensitiveCompare(_:)))
let milesSortDescriptor = NSSortDescriptor(key: "mealname",
ascending: true, selector: #selector(NSString.caseInsensitiveCompare(_:)))
fetchRequest.sortDescriptors = [timeSortDescriptor, milesSortDescriptor]
return fetchRequest
}
// MARK: - TableView data source
func numberOfSections(in tableView: UITableView) -> Int {
let numberOfSections = fetchedResultController.sections?.count
return numberOfSections!
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
let numberOfRowsInSection = fetchedResultController.sections?[section].numberOfObjects
return numberOfRowsInSection!
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
let mealstats = fetchedResultController.object(at: indexPath) as! MealStats
cell.textLabel?.text = mealstats.mealtype
cell.detailTextLabel!.text = mealstats.mealname
return cell
}
// MARK: - TableView Deleteƒ
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
let managedObject:NSManagedObject = fetchedResultController.object(at: indexPath) as! NSManagedObject
managedObjectContext.delete(managedObject)
do {
try managedObjectContext.save()
} catch _ {
}
}
// MARK: - TableView Refresh
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.reloadData()
}
}
UIViewController with a sample image for an example
Error I get once I try to view saved core data in the tableview
是的,您可以使用UITableViewController或UIViewController與表視圖。您使用適當的重用標識符使單元出隊。確保你實現了'heightForRowAtIndexPath' – Paulw11
讓它工作? –
不,但我做了項目的更改,並與UIViewController而不是UITableViewController – rahmikg