Firebase restoring initial values in textfields after changing text value - ios

I am practicing iOS (Swift) with Firebase. the first viewcontroller retrieves all the records from firebase db and populate the tableView from an array. when the user selects an item from that tableview a new viewcontroller pops up segueing the object from the listView viewcontroller to the detail viewcontroller. data is populated to the fields successfully!
however when i try to update any of the textfield, the moment i switch to another textfield the initial value is restored in the edited textfield.
I have tried to removeAllObservers... but nothing worked. i even removed "import Firebase" and all associated objects and still it restores the initial value.
am i missing any concept here?
this is the code from the ListViewController:
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated);
self.activityIndicator.startAnimating();
self.observeIngrdUpdates = ref.observeEventType(.Value, withBlock: { (snapshot) in
self.ingredients.removeAll();
for child in snapshot.children {
var nutrition:String = "";
var type:Int = 0;
var desc:String = "";
var img:String = "";
var name:String = "";
var price:Double = 0.0;
if let _name = child.value["IngredientName"] as? String {
name = _name;
}
if let _nutrition = child.value["NutritionFacts"] as? String {
nutrition = _nutrition;
}
if let _type = child.value["IngredientType"] as? Int {
type = _type;
}
if let _desc = child.value["UnitDescription"] as? String {
desc = _desc;
}
if let _img = child.value["IngredientImage"] as? String {
img = _img;
}
if let _price = child.value["IngredientPrice"] as? Double {
price = _price;
}
let ingredient = Ingredient(name: name, type: type, image: img, unitDesc: desc, nutritionFacts: nutrition, price: price);
ingredient.key = child.key;
self.ingredients.append(ingredient);
}
self.tableView.reloadData();
})
}
and the PrepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let destinationVC = segue.destinationViewController as! EditIngredientVC;
if segue.identifier?.compare(SEGUE_EDIT_INGREDIENTS) == .OrderedSame {
destinationVC.ingredient = ingredients[tableView.indexPathForSelectedRow!.row];
destinationVC.controllerTitle = "Edit";
} else if segue.identifier?.compare(SEGUE_ADD_INGREDIENT) == .OrderedSame {
destinationVC.controllerTitle = "New";
}
}
this is the code for populating the fields in DetailViewController:
override func viewDidLayoutSubviews() {
lblControllerTitle.text = controllerTitle;
if controllerTitle?.localizedCaseInsensitiveCompare("NEW") == .OrderedSame {
self.segVegFru.selectedSegmentIndex = 0;
} else {
if ingredient != nil {
self.txtIngredientName.text = ingredient!.name;
self.txtUnitDesc.text = ingredient!.unitDesc;
self.segVegFru.selectedSegmentIndex = ingredient!.typeInt;
self.txtNutritionFacts.text = ingredient!.nutritionFacts;
self.txtPrice.text = "\(ingredient!.price)";
}
}
}
Thank you all for your help.

It's probably because you are putting your textField populating code, in viewDidLayoutSubviews() method.
This method will be triggered every time the layout of a views changes in viewcontroller.
Move it to viewDidLoad() and it should be fine.
The reason that it's being reverted to the previous value is because. You are populating the textField.text from the "ingredient" object. The ingredient will have the same value retained that you passed from previous view controller. Until you mutate it at some point.
And by the way Firebase is very cool I like it too :)

Related

Problem with deleting an entity from other ViewController in CoreData

people. Im learning how to work with CoreData and i have a question.
I have a "WordArrayEntity" which have oneToMany relationship with "WordEntity" and Nulify deletion rule.
So at first when my app start im fetching info from my CoreData to special array
var wordEntities:[[WordEntity]] = []
After it my tableView recieves an attribute that it needs.
As i understand i can delete entities by this method
context.delete(wordEntity)
everything works fine when i do this on my tableView.
But, when i move to editor ViewController and try to add new Entity or delete previous nothing happens.
This is my code to move to next view controller
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
if let controller = self.storyboard?.instantiateViewController(withIdentifier: "ShowWordVC") as? ShowWordVC {
controller.word = SingleTonForEntities.shared.wordEntities[indexPath.section][indexPath.row]
controller.wordIndex = indexPath.row
self.present(controller, animated: true)
}
}
This is my method to delet word, which perfectly works at tableView
func deleteWordFromVocabulary(word: WordEntity,indexPath: Int) {
var wordStartsFromLetter = false
if let firstCharacter:Character = word.englishWord?.first {
var index = 0
for array in wordEntities {
if SingleTon.shared.sectionName[index].lowercased() == firstCharacter.lowercased() {
var newArray = array
context.delete(word)
newArray.remove(at: indexPath)
wordEntities[index] = newArray
wordStartsFromLetter = true
}
index += 1
}
}
if wordStartsFromLetter == false {
var newArray = wordEntities[26]
context.delete(word)
newArray.remove(at: indexPath)
wordEntities[26] = newArray
}
saveContext()
}
When i try to save word after editing or a new one i have the following code
#IBAction func saveButtonIsPressed(_ sender: UIButton) {
keyboardDissapears()
guard let englishWord = self.englishWordTextField.text,
!englishWord.isEmpty,
let wordImage = addedImageView.image,
let belarusianWord = self.belarusianWordTextField.text,
!belarusianWord.isEmpty,
let englishDefinition = self.englishDefinitionTextView.text,
!englishDefinition.isEmpty,
let belarusianDefinition = self.belarusianDefinitionTextView.text,
!belarusianDefinition.isEmpty else {
createAndShowAlert()
return
}
if editModeIsActivated == true {
if let wordToDelete = word, let wordIndex = wordIndex {
SingleTonForEntities.shared.deleteWordFromVocabulary(word: wordToDelete, indexPath: wordIndex)
}
}
word!.englishDefinition = englishDefinition
word!.belarusianDefinition = belarusianDefinition
word!.englishWord = englishWord
word!.belarusianWord = belarusianWord
let data = wordImage.pngData()
word!.wordImage = data
SingleTonForEntities.shared.addNewWordToVocabulary(word: self.word)
self.createAndShowDoneProgressAlert()
}
at first im checking if my fields are empty. If they aren't empty and we are in edit mode i delete the "WordEntity" from our context and then from our array.
And then i try to save a new word and add it to context with this method
func addNewWordToVocabulary(word: WordEntity!) {
var wordStartsFromLetter = false
word.englishWord = word.englishWord!.trimmingCharacters(in: .whitespacesAndNewlines)
if let firstCharacter:Character = word.englishWord?.first {
var index = 0
for array in wordEntities {
if SingleTon.shared.sectionName[index].lowercased() == firstCharacter.lowercased() {
var newArray = array
newArray.append(word)
for element in wordEntitesArray {
if element.arrayName == SingleTon.shared.sectionName[index].lowercased() {
element.addToWordEntities(word)
}
}
wordEntities[index] = newArray
wordStartsFromLetter = true
}
index += 1
}
}
if wordStartsFromLetter == false {
var newArray = wordEntities[26]
newArray.append(word)
wordEntities[26] = newArray
}
saveContext()
}
And there is a question. What am i doing wrong?
When i try to add new word to vocabulary - my app crashes.
But when im in edit mode and after it adding a new word to vocabulary - it just returns an empty tableViewCell.
I am new to CoreData and working with for about a week, but i would be glad to here what am i doing wrong and what i should do in such situations.
P.S. Everything worked well with UserDefaults

How to send multiple variables through segue

How can I send multiple variables through a segue in Swift? The QBBust gets sent over fine and prints on the view controller, but the QBName doesn't get sent over for some reason. Can anyone spot why?
if let send = sender as? Double{
destination.QBBust = send
}
if let sent = sender as? String{
destination.QBName = sent
}
}
}
private var _QBName:String!
var QBName: String{
get{
return _QBName
} set {
_QBName = newValue
}
}
private var _QBBust:Double!
var QBBust: Double {
get {
return _QBBust
} set{
_QBBust = newValue
}
}
override func viewDidLoad() {
super.viewDidLoad()
let bust = String(Int(_QBBust))
QBBustLabel.text = "\(bust)%"
QBNameLabel.text = _QBName
}
This next part is in the button function that triggers the segue
performSegue(withIdentifier: "QBResultVC", sender: QBBust)
performSegue(withIdentifier: "QBResultVC", sender: QBName)
As in Tiago's answer, you can create a new struct or class which has QBName and QBBust properties. In addition, you can also use tuple in Swift.
This is an example:
in Destination ViewController
declare var QBInfo:(name: String, bust: Double)?
and in the button function that triggers the segue
let QBInfo = (name: QBName, bust: QBBust)
performSegue(withIdentifier: "QBResultVC", sender: QBBust)
then in prepareForSegue:sender:method
destination.QBInfo = QBInfo
This question is duplicate, but you can create a Struct or new Class, and storage your data how properties and send the 'transport' object in segue.
For detail, look this answser:
Swift sending Multiple Objects to View Controller

UserDefault not being saved when going back to viewcontroller 1 and then back to viewcontroller 2

Okay so I have two view controllers. One view controller loads up all the cells that is on my Plist and the second view controller opens up the cell and shows you the description. For example:
View Controller 1:
Dog
Cat
Mouse
Click on Dog cell it will take you to View Controller 2:
Dog goes Woof.
view controller 1 is written:
ovverride func prepare(for segue: UIStoryBoardSegue, sender: Any?) {
if segue.identifier == "showDetail" {
let animals: Animals
if isFiltering() {
animals = filteredData[indexPath.row]
}
else {
animals = originalData[indexPath.row]
}
let controller = (segue.destination as! UINavigationController).topViewController as! SecondViewController
controller.detailedAnimals = animals
controller.navigationItem.leftBarButtonItem = splitViewController?.displayModeButtonItem
contrller.navigationItem.leftItemsSupplementBackButton = true
}
}
}
this is what i wrote in viewcontroller 2 updated
var isFavorite : Bool = false
#IBAction func addToFav(_ sender:UIButton) {
isFavorite = !isFavorite
UpdateButtonAppearance()
saveData()
}
private func UpdateButtonAppearance(){
if isFavorite{
let image = UIImage(named: "addFav")
favButton.setImage(image, for: . normal)
savedData()
}
else {
let image = UIImage(named: "addFavFilled")
favButton.setImage(image, for: . normal)
savedData()
}
}
ovveride func viewDidLoad(){
UpdateButtonAppearance()
saveData()
}
//updated code
func getFilePath () -> String {
var path: [AnyObject] = NSSearchPathForDirectoriesInDomains(FileManager.SearchPathDirectory.documentDirectory, FileManager.SearchPathDomainMask.userDomainMask, true) as [AnyObject]
let documentsDirectory: String = path[0] as! String
let filepath = documentsDirectory.appending("Animals.plist")
return filepath
}
func saveData(){
let myDict : NSMutableDictionary = NSMutableDictionary()
myDict["fav"] = NSNumber(booleanLiteral: isFavorite)
myDict.write(toFile: self.getFilePath(), atomically: true)
}
func getBool(){
if FileManager.default.fileExists(atPath: self.getFilePath()) {
var myDict = NSDictionary(contentsOfFile: self.getFilePath()) as!
[String:AnyObject]
let myBool: Bool = myDict["fav"]!.boolValue
isFavorite = myBool
}
I saw a tutorial on how to change the bool in the Plist and wrote it this way. The code compiles but I don't think it is changing the bool value. So on my Animals Plist i have a Item 0 type dictionary, first key is called Animal, type is string, value is "dog" and second key is Description, type is string, value is "dog goes woof" and third key is called fav, type is Bool and value is No for now but I am trying to change this value to Yes but it is not working. Also thank you so much for your comment it was easy to follow and easy to understand.
The star is not filled when you go back to the 2nd view controller because you set the images in the #IBAction func addToFav(_ sender:UIButton) method. That is when you tap the button.
You should have that part of the code in another method that you also call in didLoad().
2nd View Controller should be something like this:
var isFavorite = UserDefaults.standard.bool(forKey: "isFavorite")
func didLoad() {
super.didLoad()
updateButtonAppearance()
}
private updateButtonAppearance() {
if isFavorite {
let image = UIImage(named: "addFavFilled")
button.setImage(image, for: . normal)
}
else {
let image = UIImage(named: "addFav")
button.setImage(image, for: . normal)
}
}
#IBAction func addToFav(_ sender:UIButton) {
isFavorite = !isFavorite
UserDefaults.standard.set(isFavorite, forKey: "isFavorite")
updateButtonAppearance()
}
Also the code could be improved to not save the variable in UserDefaults in addToFav method, but whenever isFavourite is changed. Maybe you will later want to change the state of isFavourite in another method which will require code duplication.
Also note that you save a value for all pets in UserDefaults under isFavourite. That means if you favor one pet, all other pets will be favored and vice versa. Consider replacing the bool value in user defaults with a dictionary that has keys for each pet and booleans as values.

Error upon core data change processing

I am working on a coin collection app, and I have recently started integrating core data into my app. I have a core data database which stores custom CoinCategory objects and each CoinCategory object has an array of Coin objects. This way, my app stores everything in terms of categories.
When I integrated the core data, I can add my first category without any errors and delete it without any problems, but when I add in a second coin category, I experience the following error:
2017-06-26 09:55:37.218 CoinCollection[18889:12839563] -[CoinCollection.CoinCategory compare:]: unrecognized selector sent to instance 0x608000236cc0
2017-06-26 09:55:37.219215-0400 CoinCollection[18889:12839563] [error] error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[CoinCollection.CoinCategory compare:]: unrecognized selector sent to instance 0x608000236cc0 with userInfo (null)
CoreData: error: Serious application error. Exception was caught during Core Data change processing. This is usually a bug within an observer of NSManagedObjectContextObjectsDidChangeNotification. -[CoinCollection.CoinCategory compare:]: unrecognized selector sent to instance 0x608000236cc0 with userInfo (null)
Could anyone please advise me on how to fix this? Thank you very much!
I am attaching my code below for my viewcontroller and the app delegate that is running the core data.
AppDelegate.swift
// We customize the app, system-wide
import UIKit
import CoreData
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {
var window: UIWindow?
// MARK: - Core Data stack
lazy var persistentContainer: NSPersistentContainer = {
let container = NSPersistentContainer(name: "CoinCollection")
container.loadPersistentStores(completionHandler: { (storeDescription,
error) in
if let error = error as NSError? {
fatalError("Unresolved error \(error), \(error.userInfo)")
}
})
return container
}()
// MARK: - Core Data Saving support
func saveContext ()
{
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)")
}
}
}
}
And then for my view controller. Notice that I get a Coin object from a sub-viewcontroller that invokes this method, and that we decide whether the Coin object fits into the existing categories. If not, then we add the new Coin.
// Controls the table view controller showing the general coins (one per each category)
import UIKit
import CoreData
class CoinTableViewController: UITableViewController, NSFetchedResultsControllerDelegate {
//this is an array of all the coins in the collection
//each row of this two-dimensional array represents a new category
var coinsByCategory: [CoinCategoryMO] = []
var fetchResultController: NSFetchedResultsController<CoinCategoryMO>!
//other attributes....
////////////////////////////////////////////////////////////////////////
override func viewDidLoad()
{
super.viewDidLoad()
//////////////////////////////////////////////////////////////////////////////////
//we now fetch the data
let fetchRequest : NSFetchRequest<CoinCategoryMO> = CoinCategoryMO.fetchRequest()
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
{
let context = appDelegate.persistentContainer.viewContext
let sortDescriptor = NSSortDescriptor(key: "coinCategory", ascending: true)
fetchRequest.sortDescriptors = [sortDescriptor]
fetchResultController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
fetchResultController.delegate = self
do
{
try fetchResultController.performFetch()
if let fetchedObjects = fetchResultController.fetchedObjects
{
self.coinsByCategory = fetchedObjects
}
}
catch
{
print(error)
}
}
//configure even more....
}
// MARK: - Table view data soure
func deleteCoinCategory(rowPath: IndexPath)
{
if 0 <= rowPath.row && rowPath.row < self.coinsByCategory.count
{
//we have just tested that the rowPath index is valid
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
{
let context = appDelegate.persistentContainer.viewContext
let coinCategoryToDelete = self.fetchResultController.object(at: rowPath)
context.delete(coinCategoryToDelete)
appDelegate.saveContext()
}
}
}
func deleteCoin(c: Coin, indexOfSelectedCategory: IndexPath) -> Bool
{
//we have a coin that we want to delete from this viewcontroller
//and the data contained in it.
//
//the parameter indexOfSelectedCategory refers to the IndexPath of the
//row in the TableView contained in THIS viewcontroller whose category
//of coins we are modifying in this method
//
//Return value: a boolean that indicates whether a single coin has
//been deleted - meaning that the user should return to the parentviewcontroller
if 0 < indexOfSelectedCategory.row && indexOfSelectedCategory.row < self.coinsByCategory.count && self.coinsByCategory[indexOfSelectedCategory.row].coinCategory?.hasCoin(c: c) == true
{
//the index is valid as it refers to a category in the coinsByCategory array
//and the examined category has the coin in question
if self.coinsByCategory[indexOfSelectedCategory.row].coinCategory?.count == 1
{
//the coin "c" that we are going to delete is the only coin in the entire category
self.deleteCoinCategory(rowPath: indexOfSelectedCategory)
return true
}
else
{
//more than one coin in the category
self.coinsByCategory[indexOfSelectedCategory.row].coinCategory?.removeCoin(c: c)
//we save the changes in the database...
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
{
appDelegate.saveContext()
}
return false
}
}
return false
}
func addCoin(coinToAdd: Coin)
{
//we check over each category to see if the coin can be added
for category in self.coinsByCategory
{
if category.coinCategory?.coinFitsCategory(aCoin: coinToAdd) == true
{
//we can add the coin to the category
category.coinCategory?.addCoin(newCoin: coinToAdd)
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
{
//we save changes to the database
appDelegate.saveContext()
//we are DONE with this function
return
}
}
}
//since the coinToAdd does not fall in the existing categories, we create a new one
if let appDelegate = (UIApplication.shared.delegate as? AppDelegate)
{
let newCategory = CoinCategoryMO(context: appDelegate.persistentContainer.viewContext)
newCategory.coinCategory = CoinCategory(coins: [coinToAdd], categoryType: CoinCategory.CategoryTypes.COUNTRY_VALUE_AND_CURRENCY)
print("Saving data to context ...")
appDelegate.saveContext()
}
}
//delegate methods control the core data database
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
{
tableView.beginUpdates()
}
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?)
{
switch type
{
case .insert :
if let newIndexPath = newIndexPath
{
tableView.insertRows(at: [newIndexPath], with: .fade)
}
case .delete:
if let indexPath = indexPath
{
tableView.deleteRows(at: [indexPath], with: .fade)
}
case .update:
if let indexPath = indexPath
{
tableView.reloadRows(at: [indexPath], with: .fade)
}
default:
tableView.reloadData()
}
if let fetchedObjects = controller.fetchedObjects
{
self.coinsByCategory = fetchedObjects as! [CoinCategoryMO]
}
}
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>)
{
tableView.endUpdates()
}
I am looking forward to hearing your thoughts and thanks in advance for the help!
EDIT:
My code for the CoinCategory class:
// This class is supposed to represent a category of coin objects in CoreData
import Foundation
import CoreData
public class CoinCategory: NSObject, NSCoding
{
//These are the various types of categories that a user can create out of their coin collection
enum CategoryTypes : NSString
{
case COUNTRY_VALUE_AND_CURRENCY = //...
case COUNTRY = //...
case YEAR = //...
case CURRENCY = //...
case NO_CATEGORY = //...
}
//this struct is used to encode data in Key-Value pairs per the NSCoding protocol
struct Keys
{
static let Current_Category_Type = "current_category_type"
static let Coins_In_Category = "coins_in_category"
}
//this is the collection of the coins in the category
var coinsInCategory: [Coin] = [] //initially we have no coins in the collection
var currentCategoryType : CategoryTypes.RawValue = ""
public var count : NSNumber
{
get
{
//..number of coins in category
}
}
public var array : [Coin]
{
get
{
//read-only copy of the Coins array..
}
}
public required init?(coder aDecoder: NSCoder)
{
//we decode this object's information
if let categoryTypeObject = aDecoder.decodeObject(forKey: Keys.Current_Category_Type) as? CategoryTypes.RawValue
{
self.currentCategoryType = categoryTypeObject
}
if let coinsInCategoryArrayObject = aDecoder.decodeObject(forKey: Keys.Coins_In_Category) as? [Coin]
{
self.coinsInCategory = coinsInCategoryArrayObject
}
}
public func encode(with aCoder: NSCoder)
{
//we encode this object's information
aCoder.encode(currentCategoryType, forKey: Keys.Current_Category_Type)
aCoder.encode(self.coinsInCategory, forKey: Keys.Coins_In_Category)
}
override init()
{
super.init()
self.currentCategoryType = CategoryTypes.COUNTRY_VALUE_AND_CURRENCY.rawValue
self.coinsInCategory = []
}
convenience init(coins: [Coin], categoryType: CategoryTypes.RawValue)
{
self.init()
self.coinsInCategory = coins
if isACategoryType(categoryType: categoryType) == true
{
self.currentCategoryType = categoryType
}
else
{
self.currentCategoryType = CategoryTypes.NO_CATEGORY.rawValue
}
}
func isACategoryType(categoryType: NSString) -> Bool
{
switch categoryType
{
case CategoryTypes.COUNTRY_VALUE_AND_CURRENCY.rawValue:
return true
case CategoryTypes.COUNTRY.rawValue:
return true
case CategoryTypes.YEAR.rawValue:
return true
case CategoryTypes.CURRENCY.rawValue:
return true
default:
return false
}
}
func addCoin(newCoin: Coin)
{
//we are adding a new Coin object to this category
//if it falls into the category's type
if self.coinFitsCategory(aCoin: newCoin) == true
{
self.coinsInCategory.append(newCoin)
}
}
func coinFitsCategory(aCoin: Coin) -> Bool
{
//this function tests if aCoin fits into the category type
//but that all varies depending on which category the coin is
if self.coinsInCategory.count == 0
{
//this category is currently empty, so any addition goes!
return true
}
//otherwise, this category is not empty... so we are now going to
//examine the situation more critically
let testCoin = self.coinsInCategory[0]
switch self.currentCategoryType
{
case CategoryTypes.COUNTRY_VALUE_AND_CURRENCY.rawValue:
return (testCoin.getCountry().lowercased == aCoin.getCountry().lowercased) && (testCoin.getValue() == aCoin.getValue()) && (testCoin.getDenomination().lowercased == aCoin.getDenomination().lowercased)
case CategoryTypes.COUNTRY.rawValue:
return testCoin.getCountry().lowercased == aCoin.getCountry().lowercased
case CategoryTypes.CURRENCY.rawValue:
return testCoin.getDenomination().lowercased == aCoin.getDenomination().lowercased
case CategoryTypes.YEAR.rawValue:
return testCoin.getYear() == aCoin.getYear()
default:
return false
}
}
func getIndexOfCoinInCollection(coin: Coin) -> Int
{
//we are going to return -1 if the coin does not exist in the collection
//and are going to return the index otherwise if yes
for i in 0..<self.coinsInCategory.count
{
if coinsInCategory[i] == coin
{
return i
}
}
//have not found anything
return -1
}
func removeCoin(at: Int)
{
//we remove the coin at the index if it is in a valid range of the coinInCategory array
if isValidArrayIndex(index: at)
{
self.coinsInCategory.remove(at: at)
}
}
func getCoin(at: Int) -> Coin?
{
//we return nil if there is an issue in accessing the coin
if isValidArrayIndex(index: at)
{
return self.coinsInCategory[at]
}
else
{
return nil
}
}
func assignCoin(at: Int,c: Coin)
{
if isValidArrayIndex(index: at)
{
self.coinsInCategory[at].assign(right: c)
}
}
func deleteAllCoins()
{
//we delete all the coin in this category
self.coinsInCategory.removeAll()
}
func removeCoin(c: Coin)
{
//we delete a coin from the category
for i in 0..<self.coinsInCategory.count
{
if self.coinsInCategory[i] == c
{
//the coin at index "i" is equal to the coin "c" that we want to delete from the category
self.coinsInCategory.remove(at: i)
return
}
}
}
func hasCoin(c: Coin) -> Bool
{
return getIndexOfCoinInCollection(coin: c) != -1
}
func swapValuesWithAnotherCategory(other: CoinCategory)
{
swap(&self.currentCategoryType, &other.currentCategoryType)
swap(&self.coinsInCategory,&other.coinsInCategory)
}
func swapCoins(indexOne: Int, indexTwo: Int)
{
if isValidArrayIndex(index: indexOne) && isValidArrayIndex(index: indexTwo)
{
swap(&self.coinsInCategory[indexOne],&self.coinsInCategory[indexTwo])
}
}
private func isValidArrayIndex(index: Int) -> Bool
{
return (0 <= index && index < coinsInCategory.count)
}
}
And then the coin category class:
// This provides the class definition of Class Coin for the project
import UIKit
import CoreData
enum TimePeriods: String
{
//this enumeration represents the different time periods that a
//coin was minted in, for the sake of this programn
case BCE = "BCE"
case CE = "CE"
}
public class Coin : NSObject, NSCoding
{
//this struct represents all the keys used in encoding and decoding this object
struct Keys
{
static let Country = "country"
static let Mint = "mint"
static let Year = "year"
static let Currency = "currency"
static let Value = "value"
static let Grade = "grade"
static let Comments = "comments"
static let NumInstances = "numberInstances"
static let Description = "description"
static let Obverse = "obverse"
static let Reverse = "reverse"
}
//this represents a coin in the table view
static let GRADING_LOWER_LIMIT: NSNumber = 1
static let GRADING_UPPER_LIMIT: NSNumber = 70
//this represents the default strings returned if a field does not have the needed information
static let DEFAULT_DESCRIPTIVE_NAME: NSString = "(Description?)"
static let DEFAULT_COMMENTS: NSString = "(Comments?)"
static let DEFAULT_DENOMINATION: NSString = "(Denomination?)"
static let DEFAULT_MINT: NSString = "(Mint?)"
static let DEFAULT_COUNTRY: NSString = "(Country?)"
static let DEFAULT_YEAR: NSString = "(Year?)"
static let DEFAULT_GRADE: NSString = "(Grade?)"
static let DEFAULT_VALUE_AND_DENOMINATION: NSString = "(Value?) (Currency?)"
static let OBVERSE_IMAGE_STRING : NSString = "Obverse"
static let REVERSE_IMAGE_STRING : NSString = "Reverse"
static private let BULLET = "➣ " //represents the kind of bullet to be used to build a complete summary of the coin
//declare members with setters and getters
private var country: NSString = "" //what country/empire/etc. used in?
private var mint: NSString = "" //where minted? EX: US Mint, St. Petersburg
private var year: NSNumber? = nil //what year minted? per gregorian calendar
//the year can be negative to represent the BCE period
//positive to represent the CE periods
private var typeCurrency: NSString = "" //what is the unit of value? EX: Cents, dollars, centavos, etc
private var theValue: NSNumber = 0 //how many? EX: how many dollars, cents, centavos, etc.?
//additional information about the coin
private var grade: NSNumber? //on the american grading scale for coins. 1-70
private var comments: NSString = "" //extra comments stored by the user for himself
private var numberOfInstances: NSNumber = 0 //number of coins exactly like this. EX: 1,2,3,4...etc? For each instance, it must be >= 1.
//This describes the type of the coin
//EX: Walking Liberty Quarter, Barber Quarter, Standing Liberty Quarter... etc
private var descriptiveName: NSString = ""
private var obverseImage: UIImage? = nil
private var reverseImage: UIImage? = nil
public var valueAndDenomination: NSString
{
get
{
//need to check four cases
//case 1: we have the right values for value and denomination
//case 2: we do not have a value but do have denomination
//case 3: we have a value but do not have denomination
//case 4: we do not have both
//
//the reason why we consider 0 to be an empty value is because a coin that was worth
//nothing would not have been minted in the first place!!!
if (self.theValue != 0 && self.typeCurrency != "")
{
//have value and denomination
return "\(self.theValue) \(self.typeCurrency)" as NSString //like "20 Cents"
}
else if (self.theValue == 0 && self.typeCurrency != "" )
{
//do not have value, but have denomination
return "(Value?) \(self.typeCurrency)" as NSString
}
else if (self.theValue != 0 && self.typeCurrency == "")
{
//we have value, but do not have denomination
return "\(self.theValue) (Currency?)" as NSString
}
else
{
//we do not have both
return Coin.DEFAULT_VALUE_AND_DENOMINATION as NSString
}
}
}
public required init?(coder aDecoder: NSCoder)
{
//we decode this object's information
if let countryObject = aDecoder.decodeObject(forKey: Keys.Country) as? NSString
{
self.country = countryObject
}
if let mintObject = aDecoder.decodeObject(forKey: Keys.Country) as? NSString
{
self.mint = mintObject
}
if let yearObject = aDecoder.decodeObject(forKey: Keys.Year) as? NSNumber
{
self.year = yearObject
}
if let currencyObject = aDecoder.decodeObject(forKey: Keys.Currency) as? NSString
{
self.typeCurrency = currencyObject
}
if let valueObject = aDecoder.decodeObject(forKey: Keys.Value) as? NSNumber
{
self.theValue = valueObject
}
if let gradeObject = aDecoder.decodeObject(forKey: Keys.Grade) as? NSNumber
{
self.grade = gradeObject
}
if let commentObject = aDecoder.decodeObject(forKey: Keys.Comments) as? NSString
{
self.comments = commentObject
}
if let numInstancesObject = aDecoder.decodeObject(forKey: Keys.NumInstances) as? NSNumber
{
self.numberOfInstances = numInstancesObject
}
if let descriptiveNameObject = aDecoder.decodeObject(forKey: Keys.Description) as? NSString
{
self.descriptiveName = descriptiveNameObject
}
if let obverseImageObject = aDecoder.decodeObject(forKey: Keys.Obverse) as? UIImage
{
self.obverseImage = obverseImageObject
}
if let reverseImageObject = aDecoder.decodeObject(forKey: Keys.Reverse) as? UIImage
{
self.reverseImage = reverseImageObject
}
}
override init()
{
//default initializer
super.init()
self.country = ""
self.mint = ""
self.year = nil
self.typeCurrency = ""
self.theValue = 0
self.comments = ""
self.numberOfInstances = 1
self.descriptiveName = ""
self.obverseImage = nil
self.reverseImage = nil
}
init(country: NSString,year: Int?,typeCurrency: NSString, theValue: NSNumber,mint: NSString,grade: Int?,numInstances: NSNumber = 1,description: NSString, comments: NSString)
{
super.init()
self.country = country
self.mint = mint
self.year = year! as NSNumber
self.typeCurrency = typeCurrency
self.theValue = theValue
self.comments = comments
self.numberOfInstances = numInstances
self.descriptiveName = description
self.obverseImage = nil
self.reverseImage = nil
}
init(country: NSString,year: NSNumber?,typeCurrency: NSString, theValue: NSNumber,mint: NSString,grade: NSNumber?,numInstances: NSNumber = 1,description: NSString, comments: NSString,obverseImage: UIImage, reverseImage: UIImage)
{
super.init()
self.country = country
self.mint = mint
self.year = year
self.typeCurrency = typeCurrency
self.theValue = theValue
self.comments = comments
self.numberOfInstances = numInstances
self.descriptiveName = description
}
public func encode(with aCoder: NSCoder)
{
//we encode the coin's information
aCoder.encode(self.country, forKey: Keys.Country)
aCoder.encode(self.mint, forKey: Keys.Mint)
aCoder.encode(self.year, forKey: Keys.Year)
aCoder.encode(self.typeCurrency, forKey: Keys.Currency)
aCoder.encode(self.theValue, forKey: Keys.Value)
aCoder.encode(self.grade, forKey: Keys.Grade)
aCoder.encode(self.comments, forKey: Keys.Comments)
aCoder.encode(self.numberOfInstances, forKey: Keys.NumInstances)
aCoder.encode(self.descriptiveName, forKey: Keys.Description)
aCoder.encode(self.obverseImage, forKey: Keys.Obverse)
aCoder.encode(self.reverseImage, forKey: Keys.Reverse)
}
//setter and getter functions for class members...
func getCompleteSummary() -> NSString
{
//returns a bulleted list that represents the coin
//and it describes every single detail...
}
func getIncompleteSummary() -> String
{
//returns a bulleted list string that represents the coin
//and it describes every single detail...
}
/////////////////////////////////////////////////////////////////////////////////
func ofSameType(rhs: Coin) -> Bool
{
return (self.getCountry().lowercased == rhs.getCountry().lowercased) && (self.getValue() == rhs.getValue()) && (self.getDenomination().lowercased == rhs.getDenomination().lowercased)
}
public static func==(lhs: Coin, rhs: Coin) -> Bool
{
//we compare two coin objects for equality in ALL Categories
return lhs.country.lowercased == rhs.country.lowercased &&
lhs.theValue == rhs.theValue &&
lhs.typeCurrency.lowercased == rhs.typeCurrency.lowercased &&
lhs.mint.lowercased == rhs.mint.lowercased &&
lhs.year == rhs.year &&
lhs.grade == rhs.grade &&
lhs.comments == rhs.comments &&
lhs.numberOfInstances == rhs.numberOfInstances &&
lhs.descriptiveName == rhs.descriptiveName &&
lhs.obverseImage == rhs.obverseImage &&
lhs.reverseImage == rhs.reverseImage
}
func assign(right: Coin)
{
//we implement this instead of overloading the assignment "=" operator
//as it is not possible to overload the "=" operator
//we assign the right-hand-coin's field values
//to the left-hand coin's side
self.country = right.country
self.theValue = right.theValue
self.typeCurrency = right.typeCurrency
self.mint = right.mint
self.year = right.year
self.grade = right.grade
self.comments = right.comments
self.numberOfInstances = right.numberOfInstances
self.descriptiveName = right.descriptiveName
self.obverseImage = right.obverseImage
self.reverseImage = right.reverseImage
}
}
It looks like the problem is that your CoinCategory class does not implement the compare: method:
[CoinCollection.CoinCategory compare:]: unrecognized selector sent to instance 0x608000236cc0
My guess is that the FRC is trying to compare the coinCategory attribute of the second CoinCategoryMO to the coinCategory attribute of the first CoinCategoryMO in order to get them in the correct order (since your FRC is sorted using the coinCategory attribute).
So the direct answer is that you need to implement a compare: method for your CoinCategory class. But I think this is just an indicator that you need to change your approach. Rather than having an Entity with attributes that are custom objects (or collections thereof), you should probably aim to have multiple Entities (eg. a CoinMO entity, a CoinCategoryMO entity, a CoinCategoryTypeMO entity, etc) with to-many relationships between them. If you show the code for your custom objects (Coin and CoinCategory) it will be easier to advise how best to model them in CoreData.

Casting as String to Int fails

I have been having some issues with my prepareForSegue call. Whenever I try to segue to the next view controller. It gets an error and crashes at the point where I am passing the tripLikes to the next view controller.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "toDetailScene") {
//Hooking up places-holder values
let viewController = segue.destinationViewController as! DetailViewController
let cell = sender as! CustomPFTableViewCell
viewController.tripName = cell.nameTextLabel.text!
viewController.tripAuthor = cell.authorTextLabel.text!
viewController.tripLikes = Int(cell.numLikes.text!)!
viewController.tripDescrip = cell.descriptionHolder
}
}
Each of the values that we are passing to are values in the destination view controller.
You're doing a lot of force-unwrapping with Int(cell.numLikes.text!)!. If any of those values are nil, your program will crash.
Why not try something safer, such as an if-let flow:
if let text = cell.numLikes.text {
if let textInt = Int(text) {
viewController.tripLikes = textInt
} else { // Int cannot be constructed from input
viewController.tripLikes = 0
}
} else { // cell.numLikes.text was nil
viewController.tripLikes = 0
}

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