在我的tableViewController中，我有以下内容。我试图删除一个项目。
var myData: Array<AnyObject> = []
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellID: NSString = "Cell"
var Cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(cellID) as UITableViewCell
var data: NSManagedObject = myData[indexPath.row] as NSManagedObject
Cell.textLabel?.text = data.valueForKeyPath("Name") as? String
return Cell
}
然后尝试删除我有。
override func tableView(tableView: (UITableView!), commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
let cellID: NSString = "Cell"
var Cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(cellID) as UITableViewCell
var data: NSManagedObject = myData[indexPath.row] as NSManagedObject
data.delete(0)
// Delete the row from the data source
//tableView!.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
} else if editingStyle == .Insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
答案 0 :(得分：61)
在swift和coredata中执行删除数据时更新我的编码问题。这个代码我最终得到了它。
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
switch editingStyle {
case .Delete:
// remove the deleted item from the model
let appDel:AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
let context:NSManagedObjectContext = appDel.managedObjectContext!
context.deleteObject(myData[indexPath.row] as NSManagedObject)
myData.removeAtIndex(indexPath.row)
context.save(nil)
//tableView.reloadData()
// remove the deleted item from the `UITableView`
self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
default:
return
}
}
编辑以上Swift 2.2和Xcode 7.3.1
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
switch editingStyle {
case .Delete:
// remove the deleted item from the model
let appDel:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let context:NSManagedObjectContext = appDel.managedObjectContext
context.deleteObject(myData[indexPath.row] )
myData.removeAtIndex(indexPath.row)
do {
try context.save()
} catch _ {
}
// remove the deleted item from the `UITableView`
self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
default:
return
}
}
还需要纠正这两行代码。
var myData: Array<AnyObject> = []
let managedObjectContext = (UIApplication.sharedApplication().delegate as AppDelegate).managedObjectContext
答案 1 :(得分：9)
Swift 3.0
以下是删除项目和重新加载数据的代码。
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
let noteEntity = "Note" //Entity Name
let managedContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let note = notes[indexPath.row]
if editingStyle == .delete {
managedContext.delete(note)
do {
try managedContext.save()
} catch let error as NSError {
print("Error While Deleting Note: \(error.userInfo)")
}
}
//Code to Fetch New Data From The DB and Reload Table.
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: noteEntity)
do {
notes = try managedContext.fetch(fetchRequest) as! [Note]
} catch let error as NSError {
print("Error While Fetching Data From DB: \(error.userInfo)")
}
noteTableView.reloadData()
}
答案 2 :(得分：7)
要完成zisoft的答案：
删除对象后需要保存上下文。
所以正确的方法是：
// get your app managemenent context
let appDel:AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
let context = self.appDel.managedObjectContext!
// remove your object
context.del(data)
// save your changes
context.save(nil)
注意首先检查是否有任何删除规则（如果您有任何相关对象）
答案 3 :(得分：3)
不确定您的问题是什么，但您必须从NSManagedObjectContext实例中删除该对象。所以在你的commitEditingStyle函数中：
let moc = appDelegate.managedObjectContext // or something similar to get the managed object context
moc.delete(data) // your NSManagedObject
答案 4 :(得分：2)
对于Xcode 8和Swift 3.0。如果我们需要删除任何表中的所有数据，那么我们应该使用代码：
LoadStorage类文件：它还支持上面的iOS 9和iOS 10。
import UIKit
import CoreData
class localStorage: NSObject {
//MARK: - Up for iOS10 and above
@available(iOS 10.0, *)
lazy var persistentContainer: NSPersistentContainer = {
/*
The persistent container for the application. This implementation
creates and returns a container, having loaded the store for the
application to it. This property is optional since there are legitimate
error conditions that could cause the creation of the store to fail.
*/
let container = NSPersistentContainer(name: "JJS_Connect")
container.loadPersistentStores(completionHandler: { (storeDescription, error) in
if let error = error as NSError? {
// 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.
/*
Typical reasons for an error here include:
* The parent directory does not exist, cannot be created, or disallows writing.
* The persistent store is not accessible, due to permissions or data protection when the device is locked.
* The device is out of space.
* The store could not be migrated to the current model version.
Check the error message to determine what the actual problem was.
*/
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext () {
if #available(iOS 10.0, *) {
let context = persistentContainer.viewContext
if context.hasChanges {
do {
try context.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)")
}
}
}
else {
}
}
//MARK: - Usp for iOS10 below
lazy var applicationDocumentsDirectory: NSURL = {
// The directory the application uses to store the Core Data store file. This code uses a directory named "com.razeware.HitList" in the application's documents Application Support directory.
let urls = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
return urls[urls.count-1] as NSURL
}()
lazy var managedObjectModel: NSManagedObjectModel = {
// The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
let modelURL = Bundle.main.url(forResource: "JJS_Connect", withExtension: "momd")!
return NSManagedObjectModel(contentsOf: modelURL)!
}()
lazy var persistentStoreCoordinator: NSPersistentStoreCoordinator = {
// The persistent store coordinator for the application. This implementation creates and return a coordinator, having added the store for the application to it. This property is optional since there are legitimate error conditions that could cause the creation of the store to fail.
// Create the coordinator and store
let coordinator = NSPersistentStoreCoordinator(managedObjectModel: self.managedObjectModel)
let url = self.applicationDocumentsDirectory.appendingPathComponent("JJS_Connect.sqlite")
var failureReason = "There was an error creating or loading the application's saved data."
do {
try coordinator.addPersistentStore(ofType: NSSQLiteStoreType, configurationName: nil, at: url, options: nil)
} catch {
// Report any error we got.
var dict = [String: AnyObject]()
dict[NSLocalizedDescriptionKey] = "Failed to initialize the application's saved data" as AnyObject?
dict[NSLocalizedFailureReasonErrorKey] = failureReason as AnyObject?
dict[NSUnderlyingErrorKey] = error as NSError
let wrappedError = NSError(domain: "YOUR_ERROR_DOMAIN", code: 9999, userInfo: dict)
// Replace this with code to handle the error appropriately.
// abort() 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.
NSLog("Unresolved error \(wrappedError), \(wrappedError.userInfo)")
abort()
}
return coordinator
}()
lazy var managedObjectContext: NSManagedObjectContext = {
// Returns the managed object context for the application (which is already bound to the persistent store coordinator for the application.) This property is optional since there are legitimate error conditions that could cause the creation of the context to fail.
let coordinator = self.persistentStoreCoordinator
var managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = coordinator
return managedObjectContext
}()
// MARK: - Creating NSManagedObject for saving data into table
func getContext() -> NSManagedObjectContext {
if #available(iOS 10.0, *) {
let context = self.persistentContainer.viewContext
return context
}else{
let context = self.managedObjectContext
return context
}
}
}
比创建DatabaseMaster类并生成函数：
//MARK: - DELETE OPERATION FROM DB
func deleteFromAddressMaster() -> Void{
let request: NSFetchRequest<Address_master>
if #available(iOS 10.0, OSX 10.12, *) {
request = Address_master.fetchRequest()
} else {
request = NSFetchRequest(entityName: "Address_master")
}
do {
let results = try localStr.getContext().fetch(request)
for address in results {
print(" Deleted... \(address.group_id)")
localStr.getContext().delete(address)
}
} catch let error {
print(error.localizedDescription)
}
}
Address_master是子类文件名。 请定义
让localStr = localStorage（）
在DatabasMaster类文件中。
答案 5 :(得分：2)
SWIFT 5
func removeCoreData() {
guard let appDelegate =
UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let fetchRequest: NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "YourEntityName") // Find this name in your .xcdatamodeld file
let deleteRequest = NSBatchDeleteRequest(fetchRequest: fetchRequest)
do {
try managedContext.execute(deleteRequest)
} catch let error as NSError {
// TODO: handle the error
print(error.localizedDescription)
}
}
这将完全删除您存储在指定实体中的所有数据。
答案 6 :(得分：-1)
let entityDescription =
NSEntityDescription.entity(forEntityName: "Contacts",
in: managedObjectContext)
let request: NSFetchRequest<Contacts> = Contacts.fetchRequest()
request.entity = entityDescription
if let result = try? managedObjectContext.fetch(request) {
for object in result {
do {
try managedObjectContext.delete(object)
txtName?.text = ""
txtAddress?.text = ""
txtPhone?.text = ""
Status?.text = "Contact Deleted"
txtName?.text = ""
}
catch let error {
Status?.text = error.localizedDescription
}
}
}