当我将核心数据添加到 table 视图时，我的应用程序崩溃了
My app crashes when i add core data to a table view
我在一个视图控制器中有两个 table 视图，它们都保存彼此不相关的不同类型的数据。出于某种原因，每当我向任一项目添加新数据时，应用程序都会崩溃，因为它将新数据添加到两个 table 视图而不是仅一个视图。我正在尝试将数据添加到正确的 table 视图。这是我的代码。
var tasks: Todo!
var progress: [Millestone] = []
var milestone: Millestone!
var list: [Todo] = []
var taskfetch: NSFetchedResultsController<Todo>!
var progressfetch : NSFetchedResultsController<Millestone>!
let fetching: NSFetchRequest<Todo> = Todo.fetchRequest()
let sorting = NSSortDescriptor(key: "dateadded", ascending: true)
fetching.predicate = NSPredicate(format: "projectname = %@", "\(title! as String)")
fetching.sortDescriptors = [sorting]
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate) {
let context = appDelegate.persistentContainer.viewContext
taskfetch = NSFetchedResultsController(fetchRequest: fetching, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
taskfetch.delegate = self
do {
try taskfetch.performFetch()
if let fetchedObjects = taskfetch.fetchedObjects {
list = fetchedObjects
}
} catch {
print(error)
}
}
let lining: NSFetchRequest<Millestone> = Millestone.fetchRequest()
let sorting2 = NSSortDescriptor(key: "dateadded", ascending: true)
lining.predicate = NSPredicate(format: "projectname = %@", "\(title! as String)")
lining.sortDescriptors = [sorting2]
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate) {
let context = appDelegate.persistentContainer.viewContext
progressfetch = NSFetchedResultsController(fetchRequest: lining, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
progressfetch.delegate = self
do {
try progressfetch.performFetch()
if let fetchedObjects = progressfetch.fetchedObjects {
progress = fetchedObjects
}
} catch {
print(error)
}
}
func getdata() {
let context = (UIApplication.shared.delegate as! AppDelegate!).persistentContainer.viewContext
do {
print("getting")
let tasking = try context.fetch(Todo.fetchRequest())
let progressname = try context.fetch(Millestone.fetchRequest())
} catch{
print("whoopsie")
}
}
let oktaskaction = UIAlertAction(title: "Add", style: .default, handler: {(action:UIAlertAction!) -> Void in
if text.textFields?[0].text != nil, text.textFields?[0].text != "" {
// self.taskTable.beginUpdates()
// let song = self.songs[indexPath.row]
//(UIApplication.shared.delegate as! AppDelegate).saveContext()
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
self.tasks = Todo(context: appDelegate.persistentContainer.viewContext)
self.tasks.taskname = text.textFields?[0].text
self.tasks.projectname = self.title
self.tasks.completed = false
let formatter = DateFormatter()
formatter.dateStyle = DateFormatter.Style.medium
formatter.timeStyle = DateFormatter.Style.none
self.tasks.dateadded = self.date
appDelegate.saveContext()
}else {
print("nothing there")
text.textFields?[0].placeholder = "did not enter text"
}
self.taskTable.refreshControl?.beginRefreshing()
self.getdata()
self.taskTable.reloadData()
}
})
let okAction = UIAlertAction(title: "Add Milestone", style: .default, handler: {(action:UIAlertAction!) -> Void in
if text2.textFields?[0].text != nil, text2.textFields?[0].text != "", text2.textFields?[1].text != nil {
print("i'm working on adding the milestone")
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
self.milestone = Millestone(context: appDelegate.persistentContainer.viewContext)
self.milestone.progressname = text2.textFields?[0].text
self.milestone.date = text2.textFields?[1].text
self.milestone.projectname = self.title
appDelegate.saveContext()
print("adding to graph")
self.chartLegend.append(self.milestone.progressname!)
self.chartData.append(self.chartData.count + 1)
print("saved the new milestone")
}else {
print("nothing there")
text.textFields?[0].placeholder = "did not enter text"
}
self.milestoneTableView.reloadData()
self.projectlinechart.reloadData()
}
})
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
print("Begining")
print("\(list.count)")
print("\(progress.count)")
taskTable.beginUpdates()
milestoneTableView.beginUpdates()
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch type {
case .insert:
if let newIndexPath = newIndexPath {
print("adding")
taskTable.insertRows(at: [newIndexPath], with: .fade)
milestoneTableView.insertRows(at: [newIndexPath], with: .fade)
}
case .delete:
if let indexPath = indexPath {
print("delete")
taskTable.deleteRows(at: [indexPath], with: .fade)
milestoneTableView.deleteRows(at: [indexPath], with: .fade)
}
case .update:
if let indexPath = indexPath {
print("updating")
taskTable.reloadRows(at: [indexPath], with: .fade)
milestoneTableView.reloadRows(at: [indexPath], with: .fade)
}
default:
print("doing something else")
taskTable.reloadData()
milestoneTableView.reloadData()
}
if let fetchedObjects = controller.fetchedObjects {
projects = fetchedObjects as! [Project]
list = fetchedObjects as! [Todo]
progress = fetchedObjects as! [Millestone]
}
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
print("ending")
print("\(list.count)")
print("\(progress.count)")
taskTable.endUpdates()
milestoneTableView.endUpdates()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if tableView.tag == 1 {
return list.count
} else if tableView.tag == 2 {
return progress.count
} else {
return 0
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cellidentifier = "taskcell"
let cell = tableView.dequeueReusableCell(withIdentifier: cellidentifier, for: indexPath) as! TaskTableViewCell
if tableView.tag == 1 {
let tasks = list[indexPath.row]//this is where the crash occurs
cell.taskname.text = tasks.taskname
cell.taskname.adjustsFontSizeToFitWidth = true
if tasks.completed == true {
cell.accessoryType = .checkmark
}
}
} else if tableView.tag == 2 {
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
let progress2 = progress[indexPath.row]
if (progress2.progressname != nil), progress2.date != nil{
cell.progressname.text = "\(progress2.progressname!) on \(progress2.date!)"
cell.progressname.adjustsFontSizeToFitWidth = true
self.chartData.append(self.chartData.count + 1)
chartLegend.insert(cell.progressname.text!, at: indexPath.row)
} else {
cell.progressname.text = "No Milestones"
}
}
}
return cell
}
去掉下面的变量progress和list。 fetchedResultsController 正在跟踪对象的更改，因此当对象被删除、插入或移动时，它会为您更新。通过将获取的结果复制到数组中，您将在发生更改后查看过时的信息。而是直接查看 fetchedResultsController 的值（即访问 self.taskfetch.fetchedObjects 或使用 self.taskfetch.object(at:indexPath)。
导致崩溃的原因是因为您正在根据 fetchedResultsController(s) 通知您的更改更新您的 table 视图，而不是更新 table 中的行数] 因为你在看旧的陈旧数据。
另一个问题是，当任一数据集发生变化时，您都在更新 tables。因此，如果在一组数据中插入了某些内容，则您会在错误的 table 中错误地插入一行。在所有控制器方法中，首先检查它是哪个控制器。类似于 if controller == taskfetch {
我在一个视图控制器中有两个 table 视图，它们都保存彼此不相关的不同类型的数据。出于某种原因，每当我向任一项目添加新数据时，应用程序都会崩溃，因为它将新数据添加到两个 table 视图而不是仅一个视图。我正在尝试将数据添加到正确的 table 视图。这是我的代码。
var tasks: Todo!
var progress: [Millestone] = []
var milestone: Millestone!
var list: [Todo] = []
var taskfetch: NSFetchedResultsController<Todo>!
var progressfetch : NSFetchedResultsController<Millestone>!
let fetching: NSFetchRequest<Todo> = Todo.fetchRequest()
let sorting = NSSortDescriptor(key: "dateadded", ascending: true)
fetching.predicate = NSPredicate(format: "projectname = %@", "\(title! as String)")
fetching.sortDescriptors = [sorting]
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate) {
let context = appDelegate.persistentContainer.viewContext
taskfetch = NSFetchedResultsController(fetchRequest: fetching, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
taskfetch.delegate = self
do {
try taskfetch.performFetch()
if let fetchedObjects = taskfetch.fetchedObjects {
list = fetchedObjects
}
} catch {
print(error)
}
}
let lining: NSFetchRequest<Millestone> = Millestone.fetchRequest()
let sorting2 = NSSortDescriptor(key: "dateadded", ascending: true)
lining.predicate = NSPredicate(format: "projectname = %@", "\(title! as String)")
lining.sortDescriptors = [sorting2]
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate) {
let context = appDelegate.persistentContainer.viewContext
progressfetch = NSFetchedResultsController(fetchRequest: lining, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
progressfetch.delegate = self
do {
try progressfetch.performFetch()
if let fetchedObjects = progressfetch.fetchedObjects {
progress = fetchedObjects
}
} catch {
print(error)
}
}
func getdata() {
let context = (UIApplication.shared.delegate as! AppDelegate!).persistentContainer.viewContext
do {
print("getting")
let tasking = try context.fetch(Todo.fetchRequest())
let progressname = try context.fetch(Millestone.fetchRequest())
} catch{
print("whoopsie")
}
}
let oktaskaction = UIAlertAction(title: "Add", style: .default, handler: {(action:UIAlertAction!) -> Void in
if text.textFields?[0].text != nil, text.textFields?[0].text != "" {
// self.taskTable.beginUpdates()
// let song = self.songs[indexPath.row]
//(UIApplication.shared.delegate as! AppDelegate).saveContext()
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
self.tasks = Todo(context: appDelegate.persistentContainer.viewContext)
self.tasks.taskname = text.textFields?[0].text
self.tasks.projectname = self.title
self.tasks.completed = false
let formatter = DateFormatter()
formatter.dateStyle = DateFormatter.Style.medium
formatter.timeStyle = DateFormatter.Style.none
self.tasks.dateadded = self.date
appDelegate.saveContext()
}else {
print("nothing there")
text.textFields?[0].placeholder = "did not enter text"
}
self.taskTable.refreshControl?.beginRefreshing()
self.getdata()
self.taskTable.reloadData()
}
})
let okAction = UIAlertAction(title: "Add Milestone", style: .default, handler: {(action:UIAlertAction!) -> Void in
if text2.textFields?[0].text != nil, text2.textFields?[0].text != "", text2.textFields?[1].text != nil {
print("i'm working on adding the milestone")
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
self.milestone = Millestone(context: appDelegate.persistentContainer.viewContext)
self.milestone.progressname = text2.textFields?[0].text
self.milestone.date = text2.textFields?[1].text
self.milestone.projectname = self.title
appDelegate.saveContext()
print("adding to graph")
self.chartLegend.append(self.milestone.progressname!)
self.chartData.append(self.chartData.count + 1)
print("saved the new milestone")
}else {
print("nothing there")
text.textFields?[0].placeholder = "did not enter text"
}
self.milestoneTableView.reloadData()
self.projectlinechart.reloadData()
}
})
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
print("Begining")
print("\(list.count)")
print("\(progress.count)")
taskTable.beginUpdates()
milestoneTableView.beginUpdates()
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch type {
case .insert:
if let newIndexPath = newIndexPath {
print("adding")
taskTable.insertRows(at: [newIndexPath], with: .fade)
milestoneTableView.insertRows(at: [newIndexPath], with: .fade)
}
case .delete:
if let indexPath = indexPath {
print("delete")
taskTable.deleteRows(at: [indexPath], with: .fade)
milestoneTableView.deleteRows(at: [indexPath], with: .fade)
}
case .update:
if let indexPath = indexPath {
print("updating")
taskTable.reloadRows(at: [indexPath], with: .fade)
milestoneTableView.reloadRows(at: [indexPath], with: .fade)
}
default:
print("doing something else")
taskTable.reloadData()
milestoneTableView.reloadData()
}
if let fetchedObjects = controller.fetchedObjects {
projects = fetchedObjects as! [Project]
list = fetchedObjects as! [Todo]
progress = fetchedObjects as! [Millestone]
}
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
print("ending")
print("\(list.count)")
print("\(progress.count)")
taskTable.endUpdates()
milestoneTableView.endUpdates()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if tableView.tag == 1 {
return list.count
} else if tableView.tag == 2 {
return progress.count
} else {
return 0
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cellidentifier = "taskcell"
let cell = tableView.dequeueReusableCell(withIdentifier: cellidentifier, for: indexPath) as! TaskTableViewCell
if tableView.tag == 1 {
let tasks = list[indexPath.row]//this is where the crash occurs
cell.taskname.text = tasks.taskname
cell.taskname.adjustsFontSizeToFitWidth = true
if tasks.completed == true {
cell.accessoryType = .checkmark
}
}
} else if tableView.tag == 2 {
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate){
let progress2 = progress[indexPath.row]
if (progress2.progressname != nil), progress2.date != nil{
cell.progressname.text = "\(progress2.progressname!) on \(progress2.date!)"
cell.progressname.adjustsFontSizeToFitWidth = true
self.chartData.append(self.chartData.count + 1)
chartLegend.insert(cell.progressname.text!, at: indexPath.row)
} else {
cell.progressname.text = "No Milestones"
}
}
}
return cell
}
去掉下面的变量progress和list。 fetchedResultsController 正在跟踪对象的更改，因此当对象被删除、插入或移动时，它会为您更新。通过将获取的结果复制到数组中，您将在发生更改后查看过时的信息。而是直接查看 fetchedResultsController 的值（即访问 self.taskfetch.fetchedObjects 或使用 self.taskfetch.object(at:indexPath)。
导致崩溃的原因是因为您正在根据 fetchedResultsController(s) 通知您的更改更新您的 table 视图，而不是更新 table 中的行数] 因为你在看旧的陈旧数据。
另一个问题是，当任一数据集发生变化时，您都在更新 tables。因此，如果在一组数据中插入了某些内容，则您会在错误的 table 中错误地插入一行。在所有控制器方法中，首先检查它是哪个控制器。类似于 if controller == taskfetch {