I'm trying to update a progress bar with the progress of loading a load of values into CoreData. However, whenever I try to call an update on my progressView component, I get a fatal error stating that "unexpectedly found nil while unwrapping an Optional value".
The interesting thing is that this happens even if I put 'self.progressView.progress = 0.5' in the delegate method of my program - indicating that it's the progressView component it can't find rather than an issue with the value. A quick check with println also confirms the value does exist and so isn't nil. Note that if I put the 'self.progressView.progress = 0.5' statement under a function connected directly to a button, it works fine so it must be some sort of issue with the command being called from the delegate.
Can anyone work out what I'm doing wrong here? Thanks for your help.
Delegate method:
class ViewControllerUpdate: UIViewController, NSURLSessionDelegate, NSURLSessionDownloadDelegate, saveUpdate {
[....]
func updateStatus(status: String, progress: Float?) {
if let percentProgress = progress? {
self.progressView.progress = 0.5
}
//println(progress) - NOTE THIS IS CORRECTLY POPULATED WITH THE APPROPRIATE VALUE
}
Calling class:
protocol saveUpdate {
func updateStatus(status:String, progress:Float?)
}
class sqlPullSave {
let classtoUpdate: saveUpdate = ViewControllerUpdate()
func saveTSVtoSQL(fromFile: NSURL) -> Int {
//Load up the information into a Dictionary (tsv)
//let tsvURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource(fromFileName, ofType: fromFileExtension)!)
let tsvURL: NSURL = fromFile
let tab = NSCharacterSet(charactersInString: "\t")
let tsv = CSV(contentsOfURL: tsvURL, separator: tab)
//let defResult: AnyObject = tsv.rows[0]["Name"]!
//let tryagain:String = AnyObjecttoString(tsv.rows[1]["Name"]!)
//load the data into the SQLite database...
dispatch_async(dispatch_get_main_queue()) {
for a in 0..<tsv.rows.count {
self.SQLsaveLine(self.AnyObjecttoString(tsv.rows[a]["Name"]!),
name_l: "",
desc: self.AnyObjecttoString(tsv.rows[a]["1"]!),
jobTitle: self.AnyObjecttoString(tsv.rows[a]["2"]!),
extn: self.AnyObjecttoString(tsv.rows[a]["3"]!)
// update status
var percentComplete: Float = (Float(a) / Float(tsv.rows.count))
self.classtoUpdate.self.updateStatus("SQLload", progress: percentComplete)
}
}
return 0
}
Related
In Swift 2 the following code was working:
let request = NSFetchRequest(entityName: String)
but in Swift 3 it gives error:
Generic parameter "ResultType" could not be inferred
because NSFetchRequest is now a generic type. In their documents they wrote this:
let request: NSFetchRequest<Animal> = Animal.fetchRequest
so if my result class is for example Level how should I request correctly?
Because this not working:
let request: NSFetchRequest<Level> = Level.fetchRequest
let request: NSFetchRequest<NSFetchRequestResult> = Level.fetchRequest()
or
let request: NSFetchRequest<Level> = Level.fetchRequest()
depending which version you want.
You have to specify the generic type because otherwise the method call is ambiguous.
The first version is defined for NSManagedObject, the second version is generated automatically for every object using an extension, e.g:
extension Level {
#nonobjc class func fetchRequest() -> NSFetchRequest<Level> {
return NSFetchRequest<Level>(entityName: "Level");
}
#NSManaged var timeStamp: NSDate?
}
The whole point is to remove the usage of String constants.
I think i got it working by doing this:
let request:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "Level")
at least it saves and loads data from DataBase.
But it feels like it is not a proper solution, but it works for now.
The simplest structure I found that works in 3.0 is as follows:
let request = NSFetchRequest<Country>(entityName: "Country")
where the data entity Type is Country.
When trying to create a Core Data BatchDeleteRequest, however, I found that this definition does not work and it seems that you'll need to go with the form:
let request: NSFetchRequest<NSFetchRequestResult> = Country.fetchRequest()
even though the ManagedObject and FetchRequestResult formats are supposed to be equivalent.
Here are some generic CoreData methods that might answer your question:
import Foundation
import Cocoa
func addRecord<T: NSManagedObject>(_ type : T.Type) -> T
{
let entityName = T.description()
let context = app.managedObjectContext
let entity = NSEntityDescription.entity(forEntityName: entityName, in: context)
let record = T(entity: entity!, insertInto: context)
return record
}
func recordsInTable<T: NSManagedObject>(_ type : T.Type) -> Int
{
let recs = allRecords(T.self)
return recs.count
}
func allRecords<T: NSManagedObject>(_ type : T.Type, sort: NSSortDescriptor? = nil) -> [T]
{
let context = app.managedObjectContext
let request = T.fetchRequest()
do
{
let results = try context.fetch(request)
return results as! [T]
}
catch
{
print("Error with request: \(error)")
return []
}
}
func query<T: NSManagedObject>(_ type : T.Type, search: NSPredicate?, sort: NSSortDescriptor? = nil, multiSort: [NSSortDescriptor]? = nil) -> [T]
{
let context = app.managedObjectContext
let request = T.fetchRequest()
if let predicate = search
{
request.predicate = predicate
}
if let sortDescriptors = multiSort
{
request.sortDescriptors = sortDescriptors
}
else if let sortDescriptor = sort
{
request.sortDescriptors = [sortDescriptor]
}
do
{
let results = try context.fetch(request)
return results as! [T]
}
catch
{
print("Error with request: \(error)")
return []
}
}
func deleteRecord(_ object: NSManagedObject)
{
let context = app.managedObjectContext
context.delete(object)
}
func deleteRecords<T: NSManagedObject>(_ type : T.Type, search: NSPredicate? = nil)
{
let context = app.managedObjectContext
let results = query(T.self, search: search)
for record in results
{
context.delete(record)
}
}
func saveDatabase()
{
let context = app.managedObjectContext
do
{
try context.save()
}
catch
{
print("Error saving database: \(error)")
}
}
Assuming that there is a NSManagedObject setup for Contact like this:
class Contact: NSManagedObject
{
#NSManaged var contactNo: Int
#NSManaged var contactName: String
}
These methods can be used in the following way:
let name = "John Appleseed"
let newContact = addRecord(Contact.self)
newContact.contactNo = 1
newContact.contactName = name
let contacts = query(Contact.self, search: NSPredicate(format: "contactName == %#", name))
for contact in contacts
{
print ("Contact name = \(contact.contactName), no = \(contact.contactNo)")
}
deleteRecords(Contact.self, search: NSPredicate(format: "contactName == %#", name))
recs = recordsInTable(Contact.self)
print ("Contacts table has \(recs) records")
saveDatabase()
This is the simplest way to migrate to Swift 3.0, just add <Country>
(tested and worked)
let request = NSFetchRequest<Country>(entityName: "Country")
Swift 3.0 This should work.
let request: NSFetchRequest<NSFetchRequestResult> = NSManagedObject.fetchRequest()
request.entity = entityDescription(context)
request.predicate = predicate
I also had "ResultType" could not be inferred errors. They cleared once I rebuilt the data model setting each entity's Codegen to "Class Definition". I did a brief writeup with step by step instructions here:
Looking for a clear tutorial on the revised NSPersistentContainer in Xcode 8 with Swift 3
By "rebuilt" I mean that I created a new model file with new entries and attributes. A little tedious, but it worked!
What worked best for me so far was:
let request = Level.fetchRequest() as! NSFetchRequest<Level>
I had the same issue and I solved it with the following steps:
Select your xcdatamodeld file and go to the Data Model Inspector
Select your first Entity and go to Section class
Make sure that Codegen "Class Definition" is selected.
Remove all your generated Entity files. You don't need them anymore.
After doing that I had to remove/rewrite all occurences of fetchRequest as XCode seem to somehow mix up with the codegenerated version.
HTH
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
func loadItemsCategory() {
let request: NSFetchRequest<Category> = Category.fetchRequest()
do {
categoryArray = try context.fetch(request)
} catch {
print(error)
}
tableView.reloadData()
}
Im more familiar with ActionScript3 and see many similarities in Swift2, kind of why i am trying out basic coding in Swift2 and Xcode.
Here's my example:
#IBOutlet weak var b1CurrSpeed: NSTextField!
I want to store b1CurrSpeed as a string so i could access the actual textfield component to set its default value when application is loaded.
I'm aiming for Swift2 for osx apps.
Here is a fictional example, not related to any actual code:
var tf:NSTextField = this.getItem("b1CurrSpeed");
tf.stringValue = "Hello world";
Reason to this approach is following...
I would like to store textfield value in NSUserDefaults, the key for defaults would be name of that textfield. So when looping thru the defaults, i would like to get key as string and when ive got that i'd have access to actual component to set its stringvalue property.
Tho, is that good approach in Swift / xCode ?
If you want to create a function for it, do someting like this:
func getStringForKey(key: String) -> String {
guard let result = NSUserDefaults.standardUserDefaults().objectForKey(key) as! String else { return "" }
return result
}
You can set the TextFields value with myTextField.text
Swift's Mirror type can get you close to it but it is limited to NSObject subclasses, can only access stored properties and is read-only.
Yet, there are ways around these limitations if your requirements will allow.
For example, here's an extension that will save and restore defaults values for all UITextfields on a view controller using the name you gave to each IBOutlet.
extension UIViewController
{
func loadDefaults(userDefaults: NSUserDefaults)
{
for prop in Mirror(reflecting:self).children
{
// add variants for each type/property you want to support
if let field = prop.value as? UITextField,
let name = prop.label
{
if let defaultValue = userDefaults.objectForKey(name) as? String
{ field.text = defaultValue }
}
}
}
func saveDefaults(userDefaults: NSUserDefaults)
{
for prop in Mirror(reflecting:self).children
{
if let field = prop.value as? UITextField,
let name = prop.label
{
if let currentValue = field.text
{ userDefaults.setObject(currentValue, forKey: name) }
}
}
}
}
I'm trying to pass data from iPhone -> Watch via Watch Connectivity using background transfer via Application Context method.
iPhone TableViewController
private func configureWCSession() {
session?.delegate = self;
session?.activateSession()
print("Configured WC Session")
}
func getParsePassData () {
let gmtTime = NSDate()
// Query Parse
let query = PFQuery(className: "data")
query.whereKey("dateGame", greaterThanOrEqualTo: gmtTime)
query.findObjectsInBackgroundWithBlock { (objects:[AnyObject]?, error:NSError?) -> Void in
if error == nil
{
if let objectsFromParse = objects as? [PFObject]{
for MatchupObject in objectsFromParse
{
let matchupDict = ["matchupSaved" : MatchupObject]
do {
try self.session?.updateApplicationContext(matchupDict)
print("getParsePassData iPhone")
} catch {
print("error")
}
}
}
}
}
}
I'm getting error twice printed in the log (I have two matchups in Parse so maybe it knows there's two objects and thats why its throwing two errors too?):
Configured WC Session
error
error
So I haven't even gotten to the point where I can print it in the Watch app to see if the matchups passed correctly.
Watch InterfaceController:
func session(session: WCSession, didReceiveApplicationContext applicationContext: [String : AnyObject]) {
let matchupWatch = applicationContext["matchupSaved"] as? String
print("Matchups: %#", matchupWatch)
}
Any ideas? Will post any extra code that you need. Thanks!
EDIT 1:
Per EridB answer, I tried adding encoding into getParsePassData
func getParsePassData () {
let gmtTime = NSDate()
// Query Parse
let query = PFQuery(className: "data")
query.whereKey("dateGame", greaterThanOrEqualTo: gmtTime)
query.findObjectsInBackgroundWithBlock { (objects:[AnyObject]?, error:NSError?) -> Void in
if error == nil
{
if let objectsFromParse = objects as? [PFObject]{
for MatchupObject in objectsFromParse
{
let data = NSKeyedArchiver.archivedDataWithRootObject(MatchupObject)
let matchupDict = ["matchupSaved" : data]
do {
try self.session?.updateApplicationContext(matchupDict)
print("getParsePassData iPhone")
} catch {
print("error")
}
}
}
}
}
}
But get this in the log:
-[PFObject encodeWithCoder:]: unrecognized selector sent to instance 0x7fbe80d43f30
*** -[NSKeyedArchiver dealloc]: warning: NSKeyedArchiver deallocated without having had -finishEncoding called on it.
EDIT 2:
Per EridB answer, I also tried just pasting the function into my code:
func sendObjectToWatch(object: NSObject) {
//Archiving
let data = NSKeyedArchiver.archivedDataWithRootObject(MatchupObject)
//Putting it in the dictionary
let matchupDict = ["matchupSaved" : data]
//Send the matchupDict via WCSession
self.session?.updateApplicationContext(matchupDict)
}
But get this error on the first line of the function:
"Use of unresolved identifer MatchupObject"
I'm sure I must not be understanding how to use EridB's answer correctly.
EDIT 3:
NSCoder methods:
required init(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)!
//super.init(coder: aDecoder)
configureWCSession()
// Configure the PFQueryTableView
self.parseClassName = "data"
self.textKey = "matchup"
self.pullToRefreshEnabled = true
self.paginationEnabled = false
}
Error
You are getting that error, because you are putting a NSObject (MatchupObject) which does not conform to NSCoding inside the dictionary that you are going to pass.
From Apple Docs
For most types of transfers, you provide an NSDictionary object with
the data you want to send. The keys and values of your dictionary must
all be property list types, because the data must be serialized and
sent wirelessly. (If you need to include types that are not property
list types, package them in an NSData object or write them to a file
before sending them.) In addition, the dictionaries you send should be
compact and contain only the data you really need. Keeping your
dictionaries small ensures that they are transmitted quickly and do
not consume too much power on both devices.
Details
You need to archive your NSObject's to NSData and then put it in the NSDictionary. If you archive a NSObject which does not conform to NSCoding, the NSData will be nil.
This example greatly shows how to conform a NSObject to NSCoding, and if you implement these things then you just follow the code below:
//Send the dictionary to the watch
func sendObjectToWatch(object: NSObject) {
//Archiving
let data = NSKeyedArchiver.archivedDataWithRootObject(MatchupObject)
//Putting it in the dictionary
let matchupDict = ["matchupSaved" : data]
//Send the matchupDict via WCSession
self.session?.updateApplicationContext(matchupDict)
}
//When receiving object from the other side unarchive it and get the object back
func objectFromData(dictionary: NSDictionary) -> MatchupObject {
//Load the archived object from received dictionary
let data = dictionary["matchupSaved"]
//Deserialize data to MatchupObject
let matchUpObject = NSKeyedUnarchiver.unarchiveObjectWithData(data) as! MatchupObject
return matchUpObject
}
Since you are using Parse, modifying an object maybe cannot be done (I haven't used Parse in a while, so IDK for sure), but from their forum I found this question: https://parse.com/questions/is-there-a-way-to-serialize-a-parse-object-to-a-plain-string-or-a-json-string which can help you solve this problem easier than it looks above :)
I have a function, shown below, that I would like to continuously update. It is taking data from a webpage, and every so often that webpage is updated to reflect current information. Is there a way that I can catch this update and reflect that in my application? I'm pretty new to Swift and iOS programming. Some of the code made seem very bizarre, but it currently works for whatever song is playing when you first open the app (that is, it updates the text to show that song playing but doesn't update later).
let url = NSURL(string: "http://api.vicradio.org/songs/current")!
let request = NSMutableURLRequest(URL: url)
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithRequest(request) { (data: NSData?, response: NSURLResponse?, error: NSError?) in
if error != nil {
return
}
let name = NSString(data: data!, encoding: NSUTF8StringEncoding) as! String
var songName = ""
var artistName = "by "
var quoteNumber = 0
for character in name.characters {
if character == "\"" {
quoteNumber++
}
if quoteNumber == 3 && character != "\"" {
songName += String(character)
} else if quoteNumber == 7 && character != "\"" {
artistName += String(character)
}
}
if (songName != "no song metadata provided") {
self.SongNowText.text = songName
self.ArtistNowText.text = artistName
self.SongNowText.setNeedsDisplay()
self.ArtistNowText.setNeedsDisplay()
} else if (songName == "no song metadata provided") {
self.SongNowText.text = "The Best of What's Next!"
self.ArtistNowText.text = "only on VIC Radio"
}
}
task!.resume()
It looks like the URL you're accessing there is an API endpoint putting out JSON. I highly recommend using NSJSONSerialization.JSONObjectWithData to parse the response body into a dictionary and use that instead of rolling your own solution by counting quote marks.
The callback to dataTaskWithURL is executed on a background thread. Avoid updating the UI on anything besides the main thread because it can cause problems. Use dispatch_async to execute your UI update function on the main thread as in the example.
All you can do with this API is send it requests and read the responses. You can poll the endpoint at a regular interval while the app is open and get decent results from that. NSTimer is one way to do that, and it requires you put the method you want to execute repeatedly in a class inheriting from NSObject because it depends on Objective-C style message sending.
Throw this in a playground and try it:
import Cocoa
import XCPlayground
XCPSetExecutionShouldContinueIndefinitely()
class RadioDataAccessor : NSObject {
private let callback: [String : AnyObject] -> Void
init(callback: [String : AnyObject] -> Void) {
self.callback = callback
super.init()
NSTimer.scheduledTimerWithTimeInterval(5.0, target: self,
selector: "updateData", userInfo: nil, repeats: true)
// just so it happens quickly the first time
updateData()
}
func updateData() {
let session = NSURLSession.sharedSession()
let url = NSURL(string: "http://api.vicradio.org/songs/current")!
session.dataTaskWithURL(url) { data, response, error in
if error != nil {
return
}
var jsonError = NSErrorPointer()
let json = NSJSONSerialization.JSONObjectWithData(data,
options: NSJSONReadingOptions.allZeros,
error: jsonError) as? [String : AnyObject]
if jsonError != nil {
return
}
dispatch_async(dispatch_get_main_queue()) { self.callback(json!) }
}.resume()
}
}
RadioDataAccessor() { data in
println(data)
}
You may want to save the timer to a variable and expose a function that lets you invalidate it.
So I have a entity, which I am treating as a simple Database Table in iOS8 XCODE and SWIFT. I want to delete every entry in the table. Permanently. So when I start up the app again they do not reload.This is my code.
func deleteAllItems(){
println("All Items are being DELETED")
var count:Int = 0
while (HBCContactList.count > 0){
let AppDel: AppDelegate = UIApplication.sharedApplication().delegate as AppDelegate
let MOContext: NSManagedObjectContext = AppDel.managedObjectContext!
MOContext.deleteObject(HBCContactList[0] as NSManagedObject)
HBCContactList.removeAtIndex(0)
var error:NSError? = nil
if !MOContext.save(&error){
abort()
}
tableView.reloadData()
}
It looks like it loads. When its finished on the screen there is nothing in UITableView and all is good. However If I write code to return me the entity via a fetch statement and do a count on the number of records. It still says there is over 150 results.
Thoughts? Am I even in the right ball park?
One solution is to fetch the objects and delete them.
Here is an example (make sure you specify your own entity) :
// If you'll be using the Managed Object Contexte often,
// you might want to make it a lazy property :
lazy var managedObjectContext : NSManagedObjectContext? = {
let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
if let managedObjectContext = appDelegate.managedObjectContext {
return managedObjectContext
}
else {
return nil
}
}()
func deleteData() {
let context = self.managedObjectContext!
let fetchRequest = NSFetchRequest(entityName: "yourEntity")
fetchRequest.includesPropertyValues = false // Only fetch the managedObjectID (not the full object structure)
if let fetchResults = context.executeFetchRequest(fetchRequest, error: nil) as? [yourEntity] {
for result in fetchResults {
context.deleteObject(result)
}
}
var err: NSError?
if !context.save(&err) {
println("deleteData - Error : \(err!.localizedDescription)")
abort()
} else {
println("deleteData - Success")
}
}