I use Swift 4.1 and XCode 9.3
var upsList = [Any]()
func loadUpsValues () {
print("loadUpsValues")
let upsFileAsURL = URL(string: "Upslist.txt")
// Original Objective C Call was: NSMutableArray *ListUpsArray = [NSMutableArray arrayWithContentsOfURL:upsFile];
//
let upsList = NSArray(contentsOfURL:upsFileAsURL! )
}
I get an error: Ambiguous use of 'init(contentsOfURL:)'
and it seems that the source for NSArray comes from the same foundation definition:
I have twice:
1 Found this candidate (Foundation.NSArray)
2 Found this candidate (Foundation.NSArray)
Thanks for your help
This error is because [NS(Mutable)Array arrayWithContentsOfURL:]; does not exists in Swift.
For swift the NSArray initialiser has been changed to be more 'swifty' so it became:
NSArray(contentsOf:)
As seen here.
So changing your last line, the code should run as expected, i.e:
let upsList = NSArray(contentsOf: upsFileAsURL!)
Edit:
Going with the comment from #nayem. Assuming your text file is a collection of lines, you could change your code to work without relying on NS based objects like so:
func loadUpsValues () {
do {
guard let url = Bundle.main.url(forResource: "Upslist", withExtension: "txt") else { return }
let data = try String(contentsOf: url)
let upsList = data.components(separatedBy: NSCharacterSet.newlines)
...
} catch {
/* handle error */
}
}
Look at this solution:
You have declared once the upsList, why do you declare it again as a let
This solution works.
var upsList = NSArray()
func loadUpsValues () {
print("loadUpsValues")
let upsFileAsURL = URL(string: "Upslist.txt")
// Original Objective C Call was: NSMutableArray *ListUpsArray = [NSMutableArray arrayWithContentsOfURL:upsFile];
//
upsList = NSArray(contentsOf: upsFileAsURL! ) ?? NSArray()
}
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()
}
What am I doing wrong in this code?
and why do I get the error ?
"Value of type 'NSMutableArray' has no member 'append'"
static func saveUserData()
{
let item:NSDictionary = ["TIME":"12:00","LOCATION":"here"]
let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let documentsDirectory = paths[0]
let filePath = documentsDirectory + "/datafile.dat"
var readArray:NSMutableArray? = NSMutableArray(contentsOfFile: filePath)
if var array = readArray {
print("loaded array - appending..." )
// PROBLEM IS HERE
var damnArray:NSMutableArray = array
damnArray.append(item)
} else {
//
}
}
Because you are using NSMutableArray, you need to use addObject
damnArray.addObject(item)
append is used with swift array like this way
var arr = [Int]()
arr.append(5)
For more detail about swift array check this apple documentation or this tutorial.
Your had declared dammArray as NSMutableArray. So there is no method append is available. Append is available in swift array object.
var damnArray:NSMutableArray
damnArray.addObject(item)
or
var damnArray = [NSDictionary]()
damnArray.append(item)
As per your answer and syntax this worked for me thanks, in my code which is:
#IBAction func btnSend(_ sender: UIButton)
{
//data.append(tfData.text!)
data.add(tfData.text!)
tblViewList.reloadData()
tfData.resignFirstResponder()
}
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()
}
Hi I retrived value from JSON and stored in NSMutableArray. I have tried this like Singleton. I have used empty swift file for this. Datas successfully retrieved and stored in NSMutableArray which is already declared in mainViewController. Then, if I use that NSMutableArray value in mainViewController, it shows empty array.
My coding is below. Kindly guide me.
Empty Swift File
public class json_file{
var prod_Obj = product_mainVC()
class var shared: json_file
{
struct Static
{
static let instance: json_file = json_file()
}
return Static.instance
}
func dataFromJSON()
{
let url = NSURL(string: "http://........--...4900a20659")!
var data : NSData = NSData(contentsOfURL: url, options: NSDataReadingOptions.DataReadingMapped, error: nil)!
var dict: NSDictionary! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
let dataArray = dict["data"] as [[String:AnyObject]] // The array of dictionaries
for object in dataArray {
let category_name = object["category_name"] as String
prod_Obj.ct_name_arr.addObject(category_name)
let category_child = object["category_child"] as [[String:AnyObject]]
for child in category_child {
let sub_category_name = child["sub_category_name"] as String
prod_Obj.sub_ct_name_arr.addObject(sub_category_name)
}
}
println(prod_Obj.ct_name_arr) //Here value is Getting
println(prod_Obj.sub_ct_name_arr) //Here value is Getting
}
}
viewDidLoad
{
json_file.shared.dataFromJSON()
println(ct_name_arr) //Prints Empty Array [Intially Declared as NSMutableArray]
println(sub_ct_name_arr) //Prints Empty Array [Intially Declared as NSMutableArray]
}
I was trying understand the problem, but I can't see the product_mainVC. Because this I remake your class with little modifications.
class JsonFile
{
private(set) var categoryNames:[String];
private(set) var subCategoryNames:[String];
class let shared:JsonFile = JsonFile();
private init()
{
self.categoryNames = [];
self.subCategoryNames = [];
}
func dataFromJson()
{
let url = NSURL(string: "http://........--...4900a20659")!
if let data : NSData = NSData(contentsOfURL: url, options: NSDataReadingOptions.DataReadingMapped, error: nil)
{
if let dict: NSDictionary! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as? NSDictionary
{
if let dataArray = dict["data"] as? [[String:AnyObject]] // The array of dictionaries
{
for object in dataArray {
let category_id = object["category_id"] as Int
let category_name = object["category_name"] as String
categoryNames.append(category_name);
let category_child = object["category_child"] as [[String:AnyObject]]
for child in category_child {
let sub_category_id = child["sub_category_id"] as Int
let sub_category_name = child["sub_category_name"] as String
subCategoryNames.append(sub_category_name);
}
}
}
}
}
println(categoryNames);
println(subCategoryNames);
}
}
I did
Modify your way to do Singleton to a safe and more simple mode, create the arrays categoryNames and subCategoryNames internal in class because this is better to manipulate, and protect your fetch data to safe from possibles crash.
Implementation
JsonFile.shared.dataFromJson();
println("count categoryNames");
println(JsonFile.shared.categoryNames.count);
println("count subCategoryNames");
println(JsonFile.shared.subCategoryNames.count);
You need think about
This code is sync, and because this if you have a big data or request slow, the main thread from your application will freeze waiting return and it is bad for your user. Think if is necessary be sync.
let category_id = object["category_id"] as Int is never used. Why do you stay with this in code?
I'm trying to get the resolution of the camera of a device using swift.
I'm using CMVideoFormatDescriptionGetDimensions which requires a CMVideoFormatDescription, but AVCaptureDevice.formatDescription returns a CMFormatDescription. I've tried a multitude of ways to cast CMFormatDescription to CMVideoFormatDescription and can't seem to get it working.
Below is a sample of the code that I'm using:
for format in device.formats as [AVCaptureDeviceFormat] {
let videoDimensions = CMVideoFormatDescriptionGetDimensions(format.formatDescription)
}
This doesn't seem possible in Swift at the moment. One solution then would be to write a helper function in objective-c, such as:
CMVideoDimensions CMFormatDescriptionGetDimensions(CMFormatDescriptionRef formatDescription)
{
if (CMFormatDescriptionGetMediaType(formatDescription) == kCMMediaType_Video)
return CMVideoFormatDescriptionGetDimensions(formatDescription);
else
return (CMVideoDimensions) {
.width = 0,
.height = 0
};
}
Include the header with the function prototype in the Swift bridging header so that it will be accessible as a global function from your Swift code.
I was able to get the resolution using the swift method below:
let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo) as AVCaptureDevice
let formatDesc = captureDevice.activeFormat.formatDescription
let dimensions = CMVideoFormatDescriptionGetDimensions(formatDesc)
Here's a solution in pure Swift, really only usable for logging purposes and such. Paste the following function in your class or somewhere else:
func widthAndHeightFromTrack(track: AVAssetTrack) -> CGSize {
let str = track.formatDescriptions.description
let regex = try! NSRegularExpression(pattern: "[0-9]{2,4} x [0-9]{2,4}", options: [])
if let result = regex.firstMatchInString(str, options: [], range: NSMakeRange(0, str.characters.count)) {
let dimensionString = (str as NSString).substringWithRange(result.range)
let dimensionArray = dimensionString.componentsSeparatedByString(" x ")
let width = Int(dimensionArray[0])
let height = Int(dimensionArray[1])
return CGSize(width: width!, height: height!)
}
return CGSizeZero
}
Example usage:
let allTracks: AVAsset = someAVAsset.tracksWithMediaType(AVMediaTypeVideo)
let videoTrack = allTracks[0]
let videoTrackDimensions = widthAndHeightFromTrack(videoTrack)
// You now have a CGSize, print it
print("Dimensions: \(videoTrackDimensions)")
Of course, the above solution will completely break whenever Apple changes something in the string representation of the CMFormatDescription. But it's useful for logging the dimensions.
Maybe, question is too old, but the Swift issue is still not fixed.
public extension AVURLAsset {
var audioFormatDescription: CMAudioFormatDescription? {
if let track = self.tracks(withMediaType: .audio).first,
let untypedDescription = track.formatDescriptions.first {
// hacks, warnings, disablings of swiftlint below are wrork-around of
// Swift bug: it fails converting 'Any as CMFormatDescription'
let forceTyped: CMFormatDescription?
//swiftlint:disable force_cast
= untypedDescription as! CMAudioFormatDescription
//swiftlint:enable force_cast
if let description = forceTyped {
return description
} else {
return nil
}
} else {
return nil
}
}
}