In my swift code below the goal is to delete the first item in the core data boolean attribute. My code is not working below but its close to what I used to successfully fetch a boolean value. I don't really know what to add. There is a base class and a helper class.
class ViewController: UIViewController {
func deleteBool(imageNo:Int) {
// first check the array bounds
let info = helpBool.shareInstance.fetchBool()
if info.count > imageNo {
}
}
override func viewDidLoad() {
super.viewDidLoad()
deleteBool(imageNo: 1)}}
HELPER CLASS
class helpBool: UIViewController{
static let shareInstance = helpBool()
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
func deleteBool(_ boolean: Bool) {
let imageInstance = OnOff(context: context)
imageInstance.bool = boolean
do {
try context.delete()
print("text is saved")
} catch {
print(error.localizedDescription)
}
}
Related
In my swift code below the goal is to get the amount of core data attributes saved into core data. I am receiving the error message No exact matches in call to initializer at indexBox.text = String(info?). I don't know what to do next.
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let info = CoredataHandler.fetchObject()?.count
indexBox.text = String(info?)
}
}
class CoredataHandler : NSManagedObject {
class func fetchObject() -> [User]?
{
let context = getContext()
var user : [User]? = nil
do {
user = try context.fetch(User.fetchRequest())
return user
} catch {
return user
}
}
}
In my swift code below the goal would be to inverse whatever the boolean sign is. Right now the code just deletes the current boolean value which is at user1. So say user1 is true when it is inserted in into the function I would like to reverse to false instead of deleting it in core data how do I do that?
class ViewController: UIViewController {
override func viewDidLo
if CoredataHandler.deleteObject(user: user![1]) {
user = CoredataHandler.fetchObject()
print("after single")
for i in user! {
print(i.username!)
}
}
}
}
class CoredataHandler : NSManagedObject {
private class func getContext() -> NSManagedObjectContext {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
return appDelegate.persistentContainer.viewContext
}
class func fetchObject() -> [User]?
{
let context = getContext()
var user : [User]? = nil
do {
user = try context.fetch(User.fetchRequest())
return user
} catch {
return user
}
}
class func deleteObject(user: User) -> Bool
{
let context = getContext()
let delete = NSBatchDeleteRequest(fetchRequest: User.fetchRequest())
do {
try context.execute(delete)
return true
} catch {
return false
}
}
}
I'm trying to write some UnitTests for the first time. My pattern is MVP and I'm trying to test my Presenter. I've created mock class: class TeamViewMock: TeamViewPresenterProtocol { }. It contains all the methods from my real Presenter. Inside the each method I'm trying to set the new value for the property, so when the method called - property should get a new value.
Only one property gets new value out of 4 and I've no clue why the other ones didn't get it.
You may see it in the following code
import XCTest
#testable import NHL
class TeamViewPresenterTest: XCTestCase {
var presenter: TeamViewPresenter!
var viewMock: TeamViewMock!
func setupPresenter() {
viewMock = TeamViewMock()
presenter = TeamViewPresenter(with: viewMock)
}
func testGetData() {
setupPresenter()
presenter.getData(completion: {_ in })
XCTAssertTrue(viewMock.isStart) // This one works and returns true
XCTAssertTrue(viewMock.isStop) // Return error
XCTAssertTrue(viewMock.isEndRefreshing) // Return error
XCTAssertTrue(viewMock.isReload) // Return error
}
}
class TeamViewMock: TeamViewPresenterProtocol {
var isStart = false
var isStop = false
var isEndRefreshing = false
var isReload = false
func startAnimating() {
self.isStart = true // Testing stops here and doesn't go any further...
}
func stopAnimating() {
self.isStop = true
}
func endRefreshing() {
self.isEndRefreshing = true
}
func reloadView(_ teams: NHLDTO) {
self.isReload = true
}
}
class TeamViewPresenter {
// MARK: - Public Properties
private weak var view: TeamViewPresenterProtocol?
public let dataFetcherService = DataFetcherService()
// MARK: - Initializers
init(with view: TeamViewPresenterProtocol) {
self.view = view
}
// MARK: - Public Methods
public func getData(completion: #escaping (AppError) -> Void) {
view?.startAnimating() // Testing stops here and doesn't go any further, but still returns true for the property isStart and error for the rest
dataFetcherService.fetchTeamData { [weak self] result in
guard let self = self else { return }
switch result {
case .failure(let error):
completion(error)
print(error)
case .success(let teams):
guard let teams = teams else { return }
self.view?.reloadView(teams)
self.view?.stopAnimating()
self.view?.endRefreshing()
}
}
}
}
protocol TeamViewPresenterProtocol: AnyObject {
func startAnimating()
func stopAnimating()
func reloadView(_ teams: NHLDTO)
func endRefreshing()
}
This is the barcode scanning tutorial I used in my program, so that you have a lot more context when you read my code: Link
Here is what my program does so far: Essentially, when I scan an item's barcode with my phone, the UIAlert pops up with the barcode ID displayed and a button prompting the user to open the "Results" page. This is all fine and good, but how do I pass that same scanned barcode ID into a label on the Result's page? I have been stuck on this for 2 days now, even though it seems like such an easy task.
Any help is much appreciated <3
Here is my relevant code:
ProductCatalog.plist ->
Link to Image
Scanner_ViewController.swift (first View Controller) ->
import UIKit
import AVFoundation
class Scanner_ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate, ScannerDelegate
{
private var scanner: Scanner?
override func viewDidLoad()
{
super.viewDidLoad()
self.scanner = Scanner(withDelegate: self)
guard let scanner = self.scanner else
{
return
}
scanner.requestCaptureSessionStartRunning()
}
override func didReceiveMemoryWarning()
{
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// Mark - AVFoundation delegate methods
public func metadataOutput(_ output: AVCaptureMetadataOutput,
didOutput metadataObjects: [AVMetadataObject],
from connection: AVCaptureConnection)
{
guard let scanner = self.scanner else
{
return
}
scanner.metadataOutput(output,
didOutput: metadataObjects,
from: connection)
}
// Mark - Scanner delegate methods
func cameraView() -> UIView
{
return self.view
}
func delegateViewController() -> UIViewController
{
return self
}
func scanCompleted(withCode code: String)
{
print(code)
showAlert_Success(withTitle: (code))
}
private func showAlert_Success(withTitle title: String)
{
let alertController = UIAlertController(title: title, message: "Product has been successfully scanned", preferredStyle: .alert)
// programatically segue to the next view controller when the UIAlert pops up
alertController.addAction(UIAlertAction(title:"Get Results", style: .default, handler:{ action in self.performSegue(withIdentifier: "toAnalysisPage", sender: self) }))
present(alertController, animated: true)
}
}
Scanner.Swift (accompanies Scanner_ViewController.swift)->
import Foundation
import UIKit
import AVFoundation
protocol ScannerDelegate: class
{
func cameraView() -> UIView
func delegateViewController() -> UIViewController
func scanCompleted(withCode code: String)
}
class Scanner: NSObject
{
public weak var delegate: ScannerDelegate?
private var captureSession : AVCaptureSession?
init(withDelegate delegate: ScannerDelegate)
{
self.delegate = delegate
super.init()
self.scannerSetup()
}
private func scannerSetup()
{
guard let captureSession = self.createCaptureSession()
else
{
return
}
self.captureSession = captureSession
guard let delegate = self.delegate
else
{
return
}
let cameraView = delegate.cameraView()
let previewLayer = self.createPreviewLayer(withCaptureSession: captureSession,
view: cameraView)
cameraView.layer.addSublayer(previewLayer)
}
private func createCaptureSession() -> AVCaptureSession?
{
do
{
let captureSession = AVCaptureSession()
guard let captureDevice = AVCaptureDevice.default(for: .video) else
{
return nil
}
let deviceInput = try AVCaptureDeviceInput(device: captureDevice)
let metaDataOutput = AVCaptureMetadataOutput()
// add device input
if captureSession.canAddInput(deviceInput) && captureSession.canAddOutput(metaDataOutput)
{
captureSession.addInput(deviceInput)
captureSession.addOutput(metaDataOutput)
guard let delegate = self.delegate,
let viewController = delegate.delegateViewController() as? AVCaptureMetadataOutputObjectsDelegate else
{
return nil
}
metaDataOutput.setMetadataObjectsDelegate(viewController,
queue: DispatchQueue.main)
metaDataOutput.metadataObjectTypes = self.metaObjectTypes()
return captureSession
}
}
catch
{
// handle error
}
return nil
}
private func createPreviewLayer(withCaptureSession captureSession: AVCaptureSession,
view: UIView) -> AVCaptureVideoPreviewLayer
{
let previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
previewLayer.frame = view.layer.bounds
previewLayer.videoGravity = .resizeAspectFill
return previewLayer
}
private func metaObjectTypes() -> [AVMetadataObject.ObjectType]
{
return [.qr,
.code128,
.code39,
.code39Mod43,
.code93,
.ean13,
.ean8,
.interleaved2of5,
.itf14,
.pdf417,
.upce
]
}
public func metadataOutput(_ output: AVCaptureMetadataOutput,
didOutput metadataObjects: [AVMetadataObject],
from connection: AVCaptureConnection)
{
self.requestCaptureSessionStopRunning()
guard let metadataObject = metadataObjects.first,
let readableObject = metadataObject as? AVMetadataMachineReadableCodeObject,
let scannedValue = readableObject.stringValue,
let delegate = self.delegate
else
{
return
}
delegate.scanCompleted(withCode: scannedValue)
}
public func requestCaptureSessionStartRunning()
{
self.toggleCaptureSessionRunningState()
}
public func requestCaptureSessionStopRunning()
{
self.toggleCaptureSessionRunningState()
}
private func toggleCaptureSessionRunningState()
{
guard let captureSession = self.captureSession
else
{
return
}
if !captureSession.isRunning
{
captureSession.startRunning()
}
else
{
captureSession.stopRunning()
}
}
}
Analysis_ViewController.swift (second view controller) ->
Right now, the forKey: has been hard-coded to item ID 8710908501708 because I have no idea how to actually pass camera-scanned ID's into the second View Controller :/
import UIKit
class Analysis_ViewController: UIViewController
{
#IBOutlet weak var productTitle: UILabel!
func getData()
{
let path = Bundle.main.path(forResource:"ProductCatalog", ofType: "plist")
let dict:NSDictionary = NSDictionary(contentsOfFile: path!)!
if (dict.object(forKey: "8710908501708" as Any) != nil)
{
if let levelDict:[String : Any] = dict.object(forKey: "8710908501708" as Any) as? [String : Any]
{
// use a for loop to iterate through all the keys and values in side the "Levels" dictionary
for (key, value) in levelDict
{
// if we find a key named whatever we care about, we can print out the value
if (key == "name")
{
productTitle.text = (value as! String)
}
}
}
}
}
// listing the better options that are safer in comparison to the scanned product image
override func viewDidLoad()
{
super.viewDidLoad()
getData()
}
}
Do you have a variable to hold the scanned ID in your view controllers? If not, you can add var itemID: String? to both Scanner_ViewController and Analysis_ViewController.
Then in your func where you get the scanned code, you can set it to the variable.
func scanCompleted(withCode code: String) {
print(code)
itemID = code // Saves the scanned code to your var
showAlert_Success(withTitle: (code))
}
For passing data to another view controller via segue, you might want to look into this UIViewController method for segues: documentation here. This answer also might help.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toAnalysisPage" {
if let viewController = segue.destination as? Analysis_ViewController {
viewController.itemID = itemID
}
}
}
I have such code a little modified from code of Eric Armstrong
Adding a closure as target to a UIButton
But there is the problem with both codes. Those from Eric does remove all target-actions on
func removeTarget(for controlEvent: UIControl.Event = .touchUpInside)
And modified code on the other hand do not remove target-actions at all. Of course it is caused by if condition, but it also means that there are no targets stored properly in Storable property.
extension UIControl: ExtensionPropertyStorable {
class Property: PropertyProvider {
static var property = NSMutableDictionary()
static func makeProperty() -> NSMutableDictionary? {
return NSMutableDictionary()
}
}
func addTarget(for controlEvent: UIControl.Event = .touchUpInside, target: #escaping (_ sender: Any) ->()) {
let key = String(describing: controlEvent)
let target = Target(target: target)
addTarget(target, action: target.action, for: controlEvent)
property[key] = target
}
func removeTarget(for controlEvent: UIControl.Event = .touchUpInside) {
let key = String(describing: controlEvent)
if let target = property[key] as? Target {
removeTarget(target, action: target.action, for: controlEvent)
property[key] = nil
}
}
}
// Wrapper class for the selector
class Target {
private let t: (_ sender: Any) -> ()
init(target t: #escaping (_ sender: Any) -> ()) { self.t = t }
#objc private func s(_ sender: Any) { t(sender) }
public var action: Selector {
return #selector(s(_:))
}
}
// Protocols with associatedtypes so we can hide the objc_ code
protocol PropertyProvider {
associatedtype PropertyType: Any
static var property: PropertyType { get set }
static func makeProperty() -> PropertyType?
}
extension PropertyProvider {
static func makeProperty() -> PropertyType? {
return nil
}
}
protocol ExtensionPropertyStorable: class {
associatedtype Property: PropertyProvider
}
// Extension to make the property default and available
extension ExtensionPropertyStorable {
typealias Storable = Property.PropertyType
var property: Storable {
get {
let key = String(describing: type(of: Storable.self))
guard let obj = objc_getAssociatedObject(self, key) as? Storable else {
if let property = Property.makeProperty() {
objc_setAssociatedObject(self, key, property, .OBJC_ASSOCIATION_RETAIN)
}
return objc_getAssociatedObject(self, key) as? Storable ?? Property.property
}
return obj
}
set {
let key = String(describing: type(of: Storable.self))
return objc_setAssociatedObject(self, key, newValue, .OBJC_ASSOCIATION_RETAIN) }
}
}
My aim is to precisely register target-actions with closures and remove them without removing all other target-actions added to given UITextField via #selector. Now I can have removed ALL or NONE of target-actions while using this approach for closure-style target actions.
UPDATE
Based on Eric Armstrong answer i have implemented my version.
But what I have experienced in version proposed by Eric was that when adding target actions to TextField on TableView list while cells appear and then removing this target actions from Text Fields while cells diseappear the previous code seems to remove all target actions on removeTarget(for:) exection. So when in other place in code like UITableViewCell I have added additional target action on totaly different target (UITableViewCell object, not this custom Target() objects) while cells was disappearing and then again appearing on screen and removeTarget(for) was executed then this other (external as I call them target actions) also was removed and never called again.
I consider that some problem was usage of [String: Target] dictionary which is value type and it was used in case of property getter in objc_getAssociatedObject where there was
objc_getAssociatedObject(self, key) as? Storable ?? Property.property
So as I understand it then there wasn't objc object for given key and Storable was nil and nil-coalescing operator was called and static value type Property.property return aka [String : Dictionary]
So it was returned by copy and Target object was stored in this copied object which wasn't permanently stored and accessed in removeTarget(for:) always as nil. So nil was passed to UIControl.removetTarget() and all target actions was always cleared!.
I have tried simple replacing [String: Target] Swift dictionary with NSMutableDictionary which is a reference type so I assume it can be stored. But this simple replacement for static variable and just returning it via nil-coalesing operator caused as I assume that there as only one such storage for Target objects and then while scrolling Table View each removeForTarget() has somehow remove all target actions from all UITextFields not only from current.
I also consider usage of String(describing: type(of: Storable.self)) as being wrong as it will be always the same for given Storable type.
Ok, I think I finally solved this issue
The main problem was usage of AssociatedKey! it needs to be done like below
https://stackoverflow.com/a/48731142/4415642
So I ended up with such code:
import UIKit
/**
* Swift 4.2 for UIControl and UIGestureRecognizer,
* and and remove targets through swift extension
* stored property paradigm.
* https://stackoverflow.com/a/52796515/4415642
**/
extension UIControl: ExtensionPropertyStorable {
class Property: PropertyProvider {
static var property = NSMutableDictionary()
static func makeProperty() -> NSMutableDictionary? {
return NSMutableDictionary()
}
}
func addTarget(for controlEvent: UIControl.Event = .touchUpInside, target: #escaping (_ sender: Any) ->()) {
let key = String(describing: controlEvent)
let target = Target(target: target)
addTarget(target, action: target.action, for: controlEvent)
property[key] = target
print("ADDED \(ObjectIdentifier(target)), \(target.action)")
}
func removeTarget(for controlEvent: UIControl.Event = .touchUpInside) {
let key = String(describing: controlEvent)
if let target = property[key] as? Target {
print("REMOVE \(ObjectIdentifier(target)), \(target.action)")
removeTarget(target, action: target.action, for: controlEvent)
property[key] = nil
}
}
}
extension UIGestureRecognizer: ExtensionPropertyStorable {
class Property: PropertyProvider {
static var property: Target?
}
func addTarget(target: #escaping (Any) -> ()) {
let target = Target(target: target)
addTarget(target, action: target.action)
property = target
}
func removeTarget() {
let target = property
removeTarget(target, action: target?.action)
property = nil
}
}
// Wrapper class for the selector
class Target {
private let t: (_ sender: Any) -> ()
init(target t: #escaping (_ sender: Any) -> ()) { self.t = t }
#objc private func s(_ sender: Any) { t(sender) }
public var action: Selector {
return #selector(s(_:))
}
deinit {
print("Deinit target: \(ObjectIdentifier(self))")
}
}
// Protocols with associatedtypes so we can hide the objc_ code
protocol PropertyProvider {
associatedtype PropertyType: Any
static var property: PropertyType { get set }
static func makeProperty() -> PropertyType?
}
extension PropertyProvider {
static func makeProperty() -> PropertyType? {
return nil
}
}
protocol ExtensionPropertyStorable: class {
associatedtype Property: PropertyProvider
}
// Extension to make the property default and available
extension ExtensionPropertyStorable {
typealias Storable = Property.PropertyType
var property: Storable {
get {
guard let obj = objc_getAssociatedObject(self, &AssociatedKeys.property) as? Storable else {
if let property = Property.makeProperty() {
objc_setAssociatedObject(self, &AssociatedKeys.property, property, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
}
return objc_getAssociatedObject(self, &AssociatedKeys.property) as? Storable ?? Property.property
}
return obj
}
set {
return objc_setAssociatedObject(self, &AssociatedKeys.property, newValue, .OBJC_ASSOCIATION_RETAIN_NONATOMIC) }
}
}
private struct AssociatedKeys {
static var property = "AssociatedKeys.property"
}