I have two entities in my core data model: CardCollection (class name CardCollectionMO) and Card (CardMO). A CardCollection can have many cards. Here's my code for saving the CardCollection with a set of new cards, which seems to be working correctly.
func saveCardInfo() {
let currentDate = createDate()
let collectionNumber = arc4random_uniform(1000000)
let cardcollection = CardCollectionMO.insertNewCollection(collectionNumber: Int64(collectionNumber), collectionTitle: collectionTitle.text!, collectionDescription: collectionDescription.text!, numberOfCards: Int16(cards.count), dateCreated: String(currentDate))
var newCard = Set<CardMO>()
for card in cards {
if let addedCard = CardMO.insertNewCard(questionText: card.questionText, answerText: card.answerText, cardNum: Int16(card.cardNum), questionImage: UIImageJPEGRepresentation(card.questionImage, 1)! as NSData) {
addedCard.cardcollection = cardcollection
newCard.insert(addedCard)
}
}
cardcollection?.addToCards(newCard as NSSet)
}
But, strange things happen when fetching the data back. Here's the code.
func fetchData() {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let managedObjectContext = appDelegate.persistentContainer.viewContext
let request = NSFetchRequest<CardCollectionMO>(entityName: "CardCollection")
do {
let results = try managedObjectContext.fetch(request)
if results.count > 0 {
for result in results {
if let collectionTitle = result.collectionTitle {
print(collectionTitle)
}
if let listOfCards = result.cards?.allObjects as? [CardMO] {
for card in listOfCards {
if let questionText = card.questionText {
print(questionText)
}
}
The code above works fine while the app is running but if I stop and restart the app, the last card in each collection is removed. I've done a listOfCards.count and its like it doesn't exist. But, if I just fetch all the cards from the Card entity, they're there. Any thoughts on what I'm doing wrong and why the last card in the collection isn't being fetched?
Related
I know that when updating multiple rows of data, NSBatchUpdateRequest is a recommended way, as it is faster and consumed less memory.
However, what if we are only updating 1 row? Should we choose to update using NSBatchUpdateRequest or NSManagedObject? Is there any rule-of-thumb to decide the choice?
Using NSManagedObject
func updateName(_ objectID: NSManagedObjectID, _ name: String) {
let coreDataStack = CoreDataStack.INSTANCE
let backgroundContext = coreDataStack.backgroundContext
backgroundContext.perform {
do {
let nsTabInfo = try backgroundContext.existingObject(with: objectID) as! NSTabInfo
nsTabInfo.name = name
RepositoryUtils.saveContextIfPossible(backgroundContext)
} catch {
backgroundContext.rollback()
error_log(error)
}
}
}
Using NSBatchUpdateRequest
func updateName(_ objectID: NSManagedObjectID, _ name: String) {
let coreDataStack = CoreDataStack.INSTANCE
let backgroundContext = coreDataStack.backgroundContext
backgroundContext.perform {
do {
let batchUpdateRequest = NSBatchUpdateRequest(entityName: "NSTabInfo")
batchUpdateRequest.predicate = NSPredicate(format: "self == %#", objectID)
batchUpdateRequest.propertiesToUpdate = ["name": name]
batchUpdateRequest.resultType = .updatedObjectIDsResultType
let batchUpdateResult = try backgroundContext.execute(batchUpdateRequest) as? NSBatchUpdateResult
guard let batchUpdateResult = batchUpdateResult else { return }
guard let managedObjectIDs = batchUpdateResult.result else { return }
let changes = [NSUpdatedObjectsKey : managedObjectIDs]
coreDataStack.mergeChanges(changes)
} catch {
backgroundContext.rollback()
error_log(error)
}
}
}
May I know how can we decide to choose NSBatchUpdateRequest or NSManagedObject, when updating 1 row?
For one/few objects (that can be easily pulled into memory without issues), it is usually easier/recommended to -
fetch NSManagedObject into NSManagedObjectContext.
Perform your updates.
Save the context.
This saves you from having to merge the same set of changes to all other contexts in the app (which may have reference to the object being updated).
This works because NSManagedObjectContext fires notifications on save() calls that can be automatically observed by other contexts (if needed).
I am trying to display the contents of a firebase database. I know that I am reading them correctly as I am able to print them as they are read in. The problem is when I call the method to display them on screen, they are "out of range".
I know this means the the methods are being called simultaneously therefore the array is empty. I have tried the "Sleep()" method and doesn't work.
//arrays of names and descriptions
var Names:[String] = []
var Desctiptions: [String] = []
inital method
override func viewDidLoad() {
super.viewDidLoad()
getRestauraunt()
//create slides
scrollView.delegate = self
slides = createSlides()
setupSlideScrollView(slides: slides)
}
func getRestauraunt(){
let db = Firestore.firestore()
db.collection("Test").getDocuments { (snapshot, err) in
if let err = err {
print("Error getting documents: \(err)")
} else {
for document in snapshot!.documents {
let name = document.get("Name") as! String
let description = document.get("Description") as! String
//print("Names: ",name," Description: ",description)
self.Names.append(name)
self.Desctiptions.append(description)
}
}
}
}
create slides method
func createSlides() -> [Slide] {
//firebase link
let slide1:Slide = Bundle.main.loadNibNamed("Slide", owner: self, options: nil)?.first as! Slide
slide1.labelTitle.text = Names[0]
}
I would like if someone could show me how to get the 'createSlides()' method to wait until the 'getRestauraunts()' method has finished. Thank you
Just call it from the end of the getrestaurant()'s getDocuments closure
func getRestauraunt(){
//as before...
} else {
for document in snapshot!.documents {
let name = document.get("Name") as! String
let description = document.get("Description") as! String
self.Names.append(name)
self.Desctiptions.append(description)
}
self.createSlides()
}
}
}
As an aside, it might also be worth creating a simple Document struct with name and description properties, and just having the one array: [Document]
This app uses CloudKit and I sync the data to Core Data locally. I believe I have the basics working with one exception. The following code checks for changes in CloudKit and allows me to save to Core Data but I have been unable to limit the downloaded changes to one single recordType (I have two recordTypes, "Patient" and "PatientList"). I thought that CKFetchRecordZoneChangesOptions() should allow filtering by recordType but everything I have read and tried only allows filtering by desiredKeys across all recordTypes, which of course is not useful for my purpose. I can limit the Core Data saves by recordType but that seems to be the wrong approach.
Any guidance would be appreciated. Xcode 8.3.3 iOS10 Swift 3
func checkUpdates() {
let operation = CKFetchDatabaseChangesOperation(previousServerChangeToken: changeToken)
let myZone : CKRecordZone = CKRecordZone(zoneName: "myPatientZone")
var zonesIDs : [CKRecordZoneID] = []
//you ONLY want changes from myPatientZone
//you ONLY allow one custom zone and you ONLY share myPatientZone
operation.recordZoneWithIDChangedBlock = { (zoneID) in
if zoneID == myZone.zoneID {
zonesIDs.append(zoneID)
}//if
}//recordZoneWithIDChangedBlock
operation.changeTokenUpdatedBlock = { (token) in
self.changeToken = token
}
operation.fetchDatabaseChangesCompletionBlock = { (token, more, error) in
if error == nil && !zonesIDs.isEmpty {
self.changeToken = token
let options = CKFetchRecordZoneChangesOptions()
options.previousServerChangeToken = self.fetchChangeToken
let fetchOperation = CKFetchRecordZoneChangesOperation(recordZoneIDs: zonesIDs, optionsByRecordZoneID: [zonesIDs[0] : options])
fetchOperation.recordChangedBlock = { (record) in
let recordName = record.recordID.recordName
let request : NSFetchRequest<Patient> = Patient.fetchRequest()
request.predicate = NSPredicate(format: "recordName = %#", recordName)
do {
let result = try self.persistentContainer.viewContext.fetch(request)
//if the record is not in the local core data
if result.isEmpty {
let patient = Patient(context: self.persistentContainer.viewContext)
patient.recordName = recordName
patient.firstName = record.object(forKey: "firstname") as? String
//all the other fields here...
try self.persistentContainer.viewContext.save()
} else {
//if the record is in core data but has been updated
let patient = result[0]
//patient.recordName - don't change
patient.firstName = record.object(forKey: "firstname") as?
//all the other fields
}//if result.isEmpty
} catch {
//add the CRS custom error handler
print("Error")
}//do catch
}//fetchOperation
//fetchOperation.recordWithIDWasDeletedBlock = { (recordID, recordType) in
//fetchOperation.recordZoneChangeTokensUpdatedBlock = { (zoneID, token, data) in
database.add(operation)
}//checkUpdates
I have entities Application and Process, one application can have many processes, but one process can only have one application. I get one specific application entity:
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = appDelegate.managedObjectContext
let appfetchRequest = NSFetchRequest(entityName: "Application")
//appfetchRequest.returnsObjectsAsFaults = false
do{
let results = try managedContext.executeFetchRequest(appfetchRequest)
applications.addObjectsFromArray(results as! [NSMutableArray])
}catch let error as NSError{
print("Jakis blad z applications entity: \(error)")
}
let predicate:NSPredicate = NSPredicate(format: "name == %#", appTitle)
let application:NSArray = applications.filteredArrayUsingPredicate(predicate)
and in this I have relationship (named applicationprocesses).
I try to get an array with these entities in many ways, but no one work.
Actually, I have:
let processes = application.valueForKey("applicationprocesses").allObjects.first
print(processes?.valueForKey("applicationprocesses"))
And this give me:
Optional({(
<NSManagedObject: 0x7f945871b7a0> (entity: Application; id: 0xd000000000080002 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Application/p2> ; data: {
appcolor = "#3F3F3F";
appicon = bed;
applabel = Proces;
applabelplural = Procesy;
applicationprocesses = (
"0xd000000000140004 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Process/p5>",
"0xd000000000100004 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Process/p4>",
"0xd000000000180004 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Process/p6>",
"0xd0000000001c0004 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Process/p7>",
"0xd0000000000c0004 <x-coredata://00C2FE4A-143B-436E-B39B-A0A32C300B68/Process/p3>"
);
companyid = 392;
id = 1261;
name = "aplikacja 1";
processescount = 5;
})
)})
I need to display these processes in a UITablewView, so I need an array.
I will be grateful for any help.
The problem you are having is not the result of a bad line of code somewhere. It is actually working as it is supposed to. But you can make it a lot easier to work with NSManagedObject
Any fetch from your database results in [AnyObject]. If you leave it like it is, you are forced to use key-value coding which is a pain and very easy to mess up.
However it is very simple to create Classes from CD Entities and downcast the fetch result. This is an awesome feature of CoreData that unfortunately is not stressed enough.
link to gist
Your related entities might look like this:
Go to Menu -> Editor -> Create....
Select the entities you want to create a subclass for.
New files will show up in your project :
Now you can use code like this :
Insert objects
Notice the .... as? Company this is the downcast.
It allows you to access the attributes from the CD Entity like you would access any attributes from a Struct or Class.
func createACompany() {
// no appDel here. appDel and managedContext are best declared in the class scope. See gist for entire ViewController
guard let moc = managedContext else { return }
guard let company = NSEntityDescription.insertNewObjectForEntityForName("Company", inManagedObjectContext: moc) as? Company else {
return // guard is handy to "abort"
}
company.name = "Apple"
guard let bob = NSEntityDescription.insertNewObjectForEntityForName("Employee", inManagedObjectContext: moc) as? Employee else {
return
}
bob.name = "Bob"
bob.company = company
do {
try moc.save()
} catch {
print("core data save error : \(error)")
}
moc.refreshAllObjects()
}
Fetch objects
func fetchCompanies() -> [Company] {
guard let moc = managedContext else { return [] }
let request = NSFetchRequest(entityName: "Company")
request.returnsObjectsAsFaults = true
do {
let results = try moc.executeFetchRequest(request)
guard let companies = results as? [Company] else {
return []
}
return companies
}catch let error as NSError{
print("core data fetch error: \(error)")
return []
}
}
Get related objects
Look closely at the guard statement.
let employeeSet = company.employees -> unwrap of optional NSSet
let employees = employeeSet.allObjects -> get all objects in the NSSet
as? [Employee] -> downcast the result of allObjects to an Array
of Employee
func getEmployees(forCompany company : Company) -> [Employee] {
guard let employeeSet = company.employees, let employees = employeeSet.allObjects as? [Employee] else {
return []
}
return employees
}
Side note:
If you change your mind about the naming of the class and you change it everywhere. Don't forget the update it here too :
The class field has to be updated.
Similar to the InterfaceBuilder. If you change the class name it will not find it anymore.
I believe that you want to get all the managed objects (process) relate to the application object you already got. We usually use the "entity" word for same things as table in database.
I'm sorry I didn't have swift version for this line of code. I'm not sure about my swift skill
NSArray *processes = [[application fristObject] objectIDsForRelationshipNamed:#"applicationprocesses"]
Then use API to convert objectID to ManagedObject
(__kindof NSManagedObject *)objectWithID:(NSManagedObjectID *)objectID;
The only problem is this API, (NSArray *)objectIDsForRelationshipNamed:(NSString *)key , only supported from version 8.3
I'm trying to repopulate my UITableView with data from another JSON call.
However my current setup doesn't seem to work, and while there are many identical questions on SO the answers I could find I've already tried.
I'm saving my API data in CoreData entity objects. And I'm filling my UITableView with my CoreData entities.
In my current setup I have 3 different API Calls that has a different amount of data, and of course different values. I need to be able to switch between these 3 datasets, and that's what I'm trying to accomplish now. (so far without progress).
I have a function called "loadSuggestions", which is where I assume my fault lies.
First I check for an internet connection.
I set the managedObjectContext
I check what API I need to call (This is determined before the function is called, and I checked that it works as intended)
I delete all the current data from the entity that it's trying to call. (I also tried to delete the data from the last data the UITableView had loaded. That didn't change anything). I also checked that this works. After deleting the data, I checked that it prints out an empty array, I also tried logging the objects it deletes to make sure.
I then fetch the new data, save it into temporary variables. Then save it to my core data.
Then I make my second API call (dependant on a variable from the first one), fetch that data and save it the same way.
I append the object to the array the UITableView fills it's cells from. (I checked that it prints out correctly as well)
And lastly I reload the tableView. (doesn't change a thing)
Here's the function:
func loadSuggestions() {
println("----- Loading Data -----")
// Check for an internet connection.
if Reachability.isConnectedToNetwork() == false {
println("ERROR: -> No Internet Connection <-")
} else {
// Set the managedContext again.
managedContext = appDelegate.managedObjectContext!
// Check what API to get the data from
if Formula == 0 {
formulaEntity = "TrialFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/entry_weekly.json")
} else if Formula == 1 {
formulaEntity = "ProFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/entry_weekly.json")
} else if Formula == 2 {
formulaEntity = "PremiumFormulaStock"
formulaAPI = NSURL(string: "http://api.com/json/proff_weekly.json")
println("Setting Entity: \(formulaEntity)")
} else if Formula == 3 {
formulaEntity = "PlatinumFormulaStock"
println("Setting Entity: \(formulaEntity)")
formulaAPI = NSURL(string: "http://api.com/json/fund_weekly.json")
}
// Delete all the current objects in the dataset
let fetchRequest = NSFetchRequest(entityName: formulaEntity)
let a = managedContext.executeFetchRequest(fetchRequest, error: nil) as! [NSManagedObject]
for mo in a {
managedContext.deleteObject(mo)
}
// Removing them from the array
stocks.removeAll(keepCapacity: false)
// Saving the now empty context.
managedContext.save(nil)
// Set up a fetch request for the API data
let entity = NSEntityDescription.entityForName(formulaEntity, inManagedObjectContext:managedContext)
var request = NSURLRequest(URL: formulaAPI!)
var data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
var formula = JSON(data: data!)
// Loop through the api data.
for (index: String, actionable: JSON) in formula["actionable"] {
// Save the data into temporary variables
stockName = actionable["name"].stringValue
ticker = actionable["ticker"].stringValue
action = actionable["action"].stringValue
suggestedPrice = actionable["suggested_price"].floatValue
weight = actionable["percentage_weight"].floatValue
// Set up CoreData for inserting a new object.
let stock = NSManagedObject(entity: entity!,insertIntoManagedObjectContext:managedContext)
// Save the temporary variables into coreData
stock.setValue(stockName, forKey: "name")
stock.setValue(ticker, forKey: "ticker")
stock.setValue(action, forKey: "action")
stock.setValue(suggestedPrice, forKey: "suggestedPrice")
stock.setValue(weight, forKey: "weight")
// Get ready for second API call.
var quoteAPI = NSURL(string: "http://dev.markitondemand.com/Api/v2/Quote/json?symbol=\(ticker)")
// Second API fetch.
var quoteRequest = NSURLRequest(URL: quoteAPI!)
var quoteData = NSURLConnection.sendSynchronousRequest(quoteRequest, returningResponse: nil, error: nil)
if quoteData != nil {
// Save the data from second API call to temporary variables
var quote = JSON(data: quoteData!)
betterStockName = quote["Name"].stringValue
lastPrice = quote["LastPrice"].floatValue
// The second API call doesn't always find something, so checking if it exists is important.
if betterStockName != "" {
stock.setValue(betterStockName, forKey: "name")
}
// This can simply be set, because it will be 0 if not found.
stock.setValue(lastPrice, forKey: "lastPrice")
} else {
println("ERROR ----------------- NO DATA for \(ticker) --------------")
}
// Error handling
var error: NSError?
if !managedContext.save(&error) {
println("Could not save \(error), \(error?.userInfo)")
}
// Append the object to the array. Which fills the UITableView
stocks.append(stock)
}
// Reload the tableview with the new data.
self.tableView.reloadData()
}
}
Currently, when I push to this viewController, this function is called in viewDidAppear like so:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(true)
tableView.allowsSelection = true
if isFirstTime {
loadSuggestions()
isFirstTime = false
}
}
It populates the tableView correctly and everything seems to work as planned.
However if I open my slide-out menu and call a function to load different data, nothing happens, here's an example function:
func platinumFormulaTapGesture() {
// Menu related actions
selectView(platinumFormulaView)
selectedMenuItem = 2
// Setting the data to load
Formula = 3
// Sets the viewController. (this will mostly be the same ViewController)
menuTabBarController.selectedIndex = 0
// Set the new title
navigationController?.navigationBar.topItem!.title = "PLATINUM FORMULA"
// And here I call the loadSuggestions function again. (this does run)
SuggestionsViewController().loadSuggestions()
}
Here's the 2 relevant tableView functions:
number of Rows:
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return stocks.count
}
And cellForRowAtIndexPath, (this is where I set up my cells with the CoreData)
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("com.mySuggestionsCell", forIndexPath: indexPath) as! mySuggestionsCell
let formulaStock = stocks[indexPath.row]
cell.stockNameLabel.text = formulaStock.valueForKey("name") as! String!
cell.tickerLabel.text = formulaStock.valueForKey("ticker") as! String!
action = formulaStock.valueForKey("action") as! String!
suggestedPrice = formulaStock.valueForKey("suggestedPrice") as! Float
let suggestedPriceString = "Suggested Price\n$\(suggestedPrice.roundTo(2))" as NSString
var suggestedAttributedString = NSMutableAttributedString(string: suggestedPriceString as String)
suggestedAttributedString.addAttributes(GrayLatoRegularAttribute, range: suggestedPriceString.rangeOfString("Suggested Price\n"))
suggestedAttributedString.addAttributes(BlueHalisRBoldAttribute, range: suggestedPriceString.rangeOfString("$\(suggestedPrice.roundTo(2))"))
cell.suggestedPriceLabel.attributedText = suggestedAttributedString
if action == "SELL" {
cell.suggestionContainer.backgroundColor = UIColor.formulaGreenColor()
}
if let lastPrice = formulaStock.valueForKey("lastPrice") as? Float {
var lastPriceString = "Last Price\n$\(lastPrice.roundTo(2))" as NSString
var lastAttributedString = NSMutableAttributedString(string: lastPriceString as String)
lastAttributedString.addAttributes(GrayLatoRegularAttribute, range: lastPriceString.rangeOfString("Last Price\n"))
percentDifference = ((lastPrice/suggestedPrice)*100.00)-100
if percentDifference > 0 && action == "BUY" {
lastAttributedString.addAttributes(RedHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference <= 0 && percentDifference > -100 && action == "BUY" {
lastAttributedString.addAttributes(GreenHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference <= 0 && percentDifference > -100 && action == "SELL" {
lastAttributedString.addAttributes(RedHalisRBoldAttribute, range: lastPriceString.rangeOfString("$\(lastPrice.roundTo(2))"))
} else if percentDifference == -100 {
lastPriceString = "Last Price\nN/A" as NSString
lastAttributedString = NSMutableAttributedString(string: lastPriceString as String)
lastAttributedString.addAttributes(GrayLatoRegularAttribute, range: lastPriceString.rangeOfString("Last Price\n"))
lastAttributedString.addAttributes(BlackHalisRBoldAttribute, range: lastPriceString.rangeOfString("N/A"))
}
cell.lastPriceLabel.attributedText = lastAttributedString
} else {
println("lastPrice nil")
}
weight = formulaStock.valueForKey("weight") as! Float
cell.circleChart.percentFill = weight
let circleChartString = "\(weight.roundTo(2))%\nWEIGHT" as NSString
var circleChartAttributedString = NSMutableAttributedString(string: circleChartString as String)
circleChartAttributedString.addAttributes(BlueMediumHalisRBoldAttribute, range: circleChartString.rangeOfString("\(weight.roundTo(2))%\n"))
circleChartAttributedString.addAttributes(BlackSmallHalisRBoldAttribute, range: circleChartString.rangeOfString("WEIGHT"))
cell.circleChartLabel.attributedText = circleChartAttributedString
cell.selectionStyle = UITableViewCellSelectionStyle.None
return cell
}
I define my appDelegate as the very first thing in my class:
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
var managedContext = NSManagedObjectContext()
I think that's all the code that could possibly be the cause of the bug. Again I think the most likely cause would be in the loadSuggestions function.
To force update the tableView I also tried calling setNeedsDisplay and setNeedsLayout both on self.view and tableView, neither of which seemed to do anything at all.
Any advice in figuring out why this tableView refuses to update would be an enormous help!
And I apologize for the walls of code, but I havn't been able to find the exact origin of the issue.
This line in the platinumFormulaTapGesture function is incorrect,
SuggestionsViewController().loadSuggestions()
This creates a new instance of SuggestionsViewController, which is not the one you have on screen. You need to get a pointer to the one you have. How you do that depends on your controller hierarchy, which you haven't explained fully enough.