我有一個奇怪的問題,我的tableview中的單元格不一致。有時它們會顯示爲空白單元格,而其他時間則會顯示正確的數據。請參閱下面的GIF。當滾動tableview時,單元格變成空白(swift)
請注意,在部分中的空白單元每次1個變化。
向tableview添加新單元格時,我也有這個問題,但關閉並重新打開應用程序總是修復它。它只是在加載時無法正確加載......但有時它的加載是正確的。請參閱下面的GIF。
我一直推薦使用reloadData(),但似乎並沒有幫助任何東西。我希望有人會看到這將知道該怎麼做。
見下面的代碼
表視圖控制器(SWIFT)
import UIKit
import CoreData
class ListItemsTVC: UITableViewController, NSFetchedResultsControllerDelegate {
// MARK: - Constants and Variables
let moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
var frc: NSFetchedResultsController = NSFetchedResultsController()
//var sequeItem: createItem?
// MARK: - App loading Functions
override func viewDidLoad() {
super.viewDidLoad()
frc = getFCR()
frc.delegate = self
do {
try frc.performFetch()
} catch {
print("Failed to perform inital fetch")
}
self.tableView.rowHeight = 62
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
self.tableView.reloadData()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
if let sections = frc.sections {
return sections.count
}
return 0
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let sections = frc.sections {
let currentSection = sections[section]
return currentSection.numberOfObjects
}
return 0
}
override func tableView(tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 28
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
if let sections = frc.sections {
let currentSection = sections[section]
return currentSection.name
}
return nil
}
func controllerWillChangeContent(controller: NSFetchedResultsController) {
tableView.beginUpdates()
}
func controllerDidChangeContent(controller: NSFetchedResultsController) {
tableView.endUpdates()
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("listContentCell", forIndexPath: indexPath) as! ListItemsTVCell
let item = frc.objectAtIndexPath(indexPath) as! Items
cell.separatorInset = UIEdgeInsets(top: 0, left: 78, bottom: 0, right: 0)
cell.itemName.text = item.name
cell.itemSection.text = item.section
cell.itemQty.text = "Qty: \(item.qty!)"
cell.itemSize.text = item.size
cell.itemPrice.text = floatToCurrency(Float(item.price!))
//cell.itemImage.image = UIImage(data: item.image!)
cell.itemID.text = String(item.id!)
return cell
}
override func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {
let delete = UITableViewRowAction(style: .Destructive, title: "Delete") { (action, indexPath) in
let item = self.frc.objectAtIndexPath(indexPath) as! Items
let id = item.id!
let request = self.fetchRequest()
let pred = NSPredicate(format: "%K == %@", "id",id)
request.predicate = pred
var fetchResults = [AnyObject]()
do {
fetchResults = try self.moc.executeFetchRequest(request)
} catch {
fatalError("Fetching Data to Delete Failed")
}
self.moc.deleteObject(fetchResults[0] as! NSManagedObject)
fetchResults.removeAtIndex(0)
do {
try self.moc.save()
} catch {
fatalError("Failed to Save after Delete")
}
}
return [delete]
}
func controller(controller: NSFetchedResultsController, didChangeSection sectionInfo: NSFetchedResultsSectionInfo, atIndex sectionIndex: Int, forChangeType type: NSFetchedResultsChangeType) {
switch type {
case NSFetchedResultsChangeType.Delete:
self.tableView.deleteSections(NSIndexSet(index: sectionIndex), withRowAnimation: UITableViewRowAnimation.Automatic)
break
case NSFetchedResultsChangeType.Insert:
self.tableView.insertSections(NSIndexSet(index: sectionIndex), withRowAnimation: UITableViewRowAnimation.Automatic)
break
/*case NSFetchedResultsChangeType.Update:
tableView.reloadSections(NSIndexSet(index: sectionIndex), withRowAnimation: UITableViewRowAnimation.Automatic)
break*/
default:
print("Default in didChangeSection was called")
break
}
}
func controller(controller: NSFetchedResultsController, didChangeObject anObject: AnyObject, atIndexPath indexPath: NSIndexPath?, forChangeType type: NSFetchedResultsChangeType, newIndexPath: NSIndexPath?) {
switch type {
case NSFetchedResultsChangeType.Delete:
self.tableView.deleteRowsAtIndexPaths([indexPath!], withRowAnimation: UITableViewRowAnimation.Automatic)
break
case NSFetchedResultsChangeType.Insert:
self.tableView.insertRowsAtIndexPaths([newIndexPath!], withRowAnimation: UITableViewRowAnimation.Fade)
break
default:
print("Default in didChangeObject was called")
break
}
}
// MARK: - Custom Functions
func fetchRequest() -> NSFetchRequest {
let fetchRequest = NSFetchRequest(entityName: "Items")
let sortDesc1 = NSSortDescriptor(key: "section", ascending: true)
let sortDesc2 = NSSortDescriptor(key: "isChecked", ascending: true)
let sortDesc3 = NSSortDescriptor(key: "name", ascending: true)
fetchRequest.sortDescriptors = [sortDesc1, sortDesc2, sortDesc3]
return fetchRequest
}
func getFCR() -> NSFetchedResultsController {
frc = NSFetchedResultsController(fetchRequest: fetchRequest(), managedObjectContext: moc, sectionNameKeyPath: "section" , cacheName: nil)
return frc
}
func floatToCurrency(flt: Float) -> String {
let formatter = NSNumberFormatter()
formatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
return String(formatter.stringFromNumber(flt)!)
}
}
添加按鈕 - 視圖 - 控制器(SWIFT)
import UIKit
import CoreData
class AddItemListVC: UIViewController, NSFetchedResultsControllerDelegate {
// MARK: - Constants and Variables
let moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
var sendItem: Items?
// MARK: - App loading Functions
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Outlets and Actions
@IBAction func addItem(sender: AnyObject) {
let entityDesc = NSEntityDescription.entityForName("Items", inManagedObjectContext: moc)
let item = Items(entity: entityDesc!, insertIntoManagedObjectContext: moc)
if (NSUserDefaults.standardUserDefaults().objectForKey("nextItemID") == nil) {
NSUserDefaults.standardUserDefaults().setObject(1, forKey: "nextItemID")
NSUserDefaults.standardUserDefaults().synchronize()
}
let id = NSUserDefaults.standardUserDefaults().integerForKey("nextItemID")
item.id = id
switch id {
case 1..<10:
item.name = "Item ID 00\(id)"
case 10..<100:
item.name = "Item ID 0\(id)"
default:
item.name = "Item ID \(id)"
}
item.brand = "Brand \(id)"
item.qty = 1
item.price = 0
item.size = "Size \(id)"
let sec: Int = Int(arc4random_uniform(UInt32(4 - 1))) + 1
item.section = "Section \(sec)"
item.isChecked = false
do {
try moc.save()
NSUserDefaults.standardUserDefaults().setObject(id + 1, forKey: "nextItemID")
NSUserDefaults.standardUserDefaults().synchronize()
} catch {
fatalError("New item save failed")
}
navigationController!.popViewControllerAnimated(true)
}
}
您可以創建與上面的代碼的東西示範項目,並分享這裏下載,所以任何人都可以看看,爲您提供解決方案。 – Hasya
其實,這是我的演示項目,我有我的實際應用這個問題,所以我建立了它儘可能的簡單,試圖找出其中的問題來自何處。這是Dropbox的一個zip文件。我很想知道其他人是否看到相同的結果。從我廣泛的研究來看,似乎我做的都是正確的。但是我可以在網上找到的大多數例子都是使用數組而不是CoreData,所以我猜這就是問題出現的地方。 –