I’ve been working on an app that I use NSLocalized Strings but when I run the app it’s showing me the key for the localized string and not the string itself.
Example:
Create a Class initializer.
class TestClass {
let name: String
init(myName: String) {
name = myName
}
}
Initialize my Test.
class TestString {
var list = [TestClass]()
init() {
list.append(TestClass(myName: NSLocalizedString("Don", comment: "Test 1")))
list.append(TestClass(myName: NSLocalizedString("Amanda", comment: "Test 2")))
}
}
And my View Controller:
class ViewController: UIViewController {
#IBOutlet weak var label: UILabel!
var allNames = TestString()
var count = 0
#IBAction func button(_ sender: UIButton) {
label.text = allNames.list[count].name
count += 1
}
}
The String file is:
"Don" = "Donald Belliveau";
"Amanda" = "Amanda Ferguson";
When I run the app, I should see my label display Donald Belliveau once I click the button but I'm seeing Don. This was working just last week (Swift 4.0) but now doesn't seem to be. Any help would be greatly appreciated.
You could try & debug the string value by using the following code:
NSLocalizedString("Don", tableName: "Localized", bundle: Bundle.main, comment: "")
Make sure:
tableName should be exactly the same as the string file name
bundle should the exactly your project bundle name.
Related
I'm very new to programming.
I am trying to update an object in my Realm database but I get always an error.
I have tried to find the issue but I can't find anyone with a similar issue.
What I'm trying to do is:
I have a Game-Score-App.
It should display the names on Tab1 and on the Tab2 I want to give the user the ability, to change the names of the players. As soon as the ViewDidDisappear I want to write the changes to Realm.
I already figured out how to update the names in the database. And it works properly the first time.
But as soon as I go a second time on the Tab2 and go back to Tab1 again, I get the message "Primary key can't be changed after an object is inserted."
Any Ideas?
class Games: Object {
#objc dynamic var game_id = UUID().uuidString
#objc dynamic var gameName: String = ""
var playerNames = List<String>()
override class func primaryKey() -> String? {
return "game_id"
}
}
class FirstPageVC: UIViewController {
#IBOutlet var playerNameLabels: [UILabel]!
#IBOutlet weak var gameNameLabel: UILabel!
let realm = try! Realm()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
let games = realm.objects(Games.self)
gameNameLabel.text = games[0].gameName
for i in 0...playerNameLabels.count - 1 {
playerNameLabels[i].text = games[0].playerNames[i]
}
}
}
class SecondPageVC: UIViewController {
#IBOutlet var playerNameTextbox: [UITextField]!
#IBOutlet weak var gameNameTextbox: UITextField!
#IBOutlet weak var numberOfIndex: UITextField!
let realm = try! Realm()
var playerNames: [String] = []
var gameName: String = ""
var game = Games()
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
if realm.objects(Games.self).count != 0 {
let games = realm.objects(Games.self)
gameNameTextbox.text = games[0].gameName
for i in 0...playerNameTextbox.count - 1 {
playerNameTextbox[i].text = games[0].playerNames[i]
}
}
}
#IBAction func addButton(_ sender: UIButton) {
gameName = gameNameTextbox.text!
for i in 0...playerNameTextbox.count - 1 {
playerNames.append(playerNameTextbox[i].text!)
}
let items = realm.objects(Games.self)
let number = Int(numberOfIndex.text!)
game.game_id = items[number!].game_id
game.gameName = gameName
game.playerNames.append(objectsIn: playerNames)
try! realm.write {
realm.add(game, update: .modified)
}
}
}
The problem is your Realm object structure. Anything that could possibly ever be changed should not be used as a primary key.
Also note from the Realm Documentation
Once an object with a primary key is added to a Realm, the primary key
cannot be changed.
To expand on that, it's often best practice to disassociate an objects key (e.g. primary key) from the rest of the properties of an object.
Here's how to do that
class Games: Object{
#objc dynamic var game_id = UUID().uuidString
#objc dynamic var gameName: String = ""
var playerNames = List<String>()
override class func primaryKey() -> String? {
return "game_id"
}
}
UUID().uuidString will generate a unique string for every object that's created and will look something like this string
CDEA69EA-AC84-4465-ABE3-DDA29D31B925
Once the object is created, you can use it to load that specific object or update it's properties.
See Objects with Primary Keys
Here's how to change the game name
let item = realm.object(ofType: Game.self, forPrimaryKey: "CDEA69EA-AC84-4465-ABE3-DDA29D31B925")!
try! realm.write {
game.gameName = "Pwn You!"
}
Try this solution:
Replace the code in viewDidDisappear after the end of for loop with the following code:
if let gameInRealm = realm.objects(Game.self).first{
try! realm.write {
gameInRealm.gameName = gameName
gameInRealm.playerNames = playerNames
}
}else{
game.gameName = gameName
game.playerNames.append(objectsIn: playerNames)
realm.add(game)
}
Explanation (if needed):
The code changes the existing Game properties in case a Game object exists. Otherwise, it creates a new one with the new properties.
Therefore, the else statement should get executed the first time you leave SecondPageVC, and then the if statement will get triggered every other time you leave SecondPageVC.
I am trying to store the value of the textfield String to Firebase but the debugger says "unable to read data (String)." Here is my code.
#IBAction func btnSelect(_ sender: Any) {
var Description: String = TextField.text ?? ""
}
Try declaring Description first outside of viewDidLoad(), then initialize it inside the function btnSelect()
I created an example without using the storyBoard and it is working
let TextField : UITextField = {
let txt = UITextField()
txt.text = "Hello World"
return txt
}()
var Description: String?
override func viewDidLoad() {
btnSelect()
}
func btnSelect() {
Description = TextField.text
print(Description)
}
If this does not work for you, it must be something to do with either how you are initializing TextField or something with your storyBoard.
Using the MVC approach for iOS app development, I would like to observe changes to the model by posting to the NotificationCenter. For my example, the Person.swift model is:
class Person {
static let nameDidChange = Notification.Name("nameDidChange")
var name: String {
didSet {
NotificationCenter.default.post(name: Person.nameDidChange, object: self)
}
}
var age: Int
var gender: String
init(name: String, age: Int, gender: String) {
self.name = name
self.age = age
self.gender = gender
}
}
The view controller that observes the model is shown below:
class ViewController: UIViewController {
let person = Person(name: "Homer", age: 44, gender: "male")
#IBOutlet weak var nameLabel: UILabel!
#IBOutlet weak var ageLabel: UILabel!
#IBOutlet weak var genderLabel: UILabel!
#IBOutlet weak var nameField: UITextField!
#IBOutlet weak var ageField: UITextField!
#IBOutlet weak var genderField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
nameLabel.text = person.name
ageLabel.text = String(person.age)
genderLabel.text = person.gender
NotificationCenter.default.addObserver(self,
selector: #selector(self.updateLabels),
name: Person.nameDidChange, object: nil)
}
#IBAction func updatePerson(_ sender: Any) {
guard let name = nameField.text, let age = ageField.text, let gender = genderField.text else { return }
guard let ageNumber = Int(age) else { return }
person.name = name
person.age = ageNumber
person.gender = gender
}
#objc func updateLabels() {
nameLabel.text = person.name
ageLabel.text = String(person.age)
genderLabel.text = person.gender
}
}
The example app works as follows:
Enter a name, age, and gender in the text fields
Press the updatePerson button to update the model from the text field values
When the model is updated, the notification observer calls the updateLabels function to update the user interface.
This approach requires the person.name to be set last otherwise the updatePerson button must be pressed twice to update the entire user interface. And since I'm only observing one property, the notification does not represent the entire class. Is there a better way to observe changes of models (a class or struct) in Swift?
Note - I am not interested in using RxSwift for this example.
This is more of a dumping comment than a fulfilling answer. But long story short KVO is the feature you should be using, not NotificationCenter. The binding process becomes significantly more simple in Swift4
As for what KVO is: See here and here. For some examples which are MVVM focused you can see here and here. And don't let the MVVM sway you away. It's just MVC with bindings which you are trying to do the exact same thing + moving the presentation logic to a different layer.
A simple KVO example in Swift 4 would look like this:
#objcMembers class Foo: NSObject {
dynamic var string: String
override init() {
string = "hotdog"
super.init()
}
}
let foo = Foo()
// Here it is, kvo in 2 lines of code!
let observation = foo.observe(\.string) { (foo, change) in
print("new foo.string: \(foo.string)")
}
foo.string = "not hotdog"
// new foo.string: not hotdog
You can also create your own Observable type like below:
class Observable<ObservedType>{
private var _value: ObservedType?
init(value: ObservedType) {
_value = value
}
var valueChanged : ((ObservedType?) -> ())?
public var value: ObservedType? {
get{
return _value // The trick is that the public value is reading from the private value...
}
set{
_value = newValue
valueChanged?(_value)
}
}
func bindingChanged(to newValue : ObservedType){
_value = newValue
print("value is now \(newValue)")
}
}
Then to create an observable property you'd do:
class User {
// var name : String <-- you normally do this, but not when you're creating as such
var name : Observable<String>
init (name: Observable<String>){
self.name = name
}
}
The class above (Observable) is copied and pasted from Swift Designs patterns book
To simply visualize the picture, you should be aware of the fact that you are observing only the name change. So it doesn't make sense to update all of the other properties of Person. You are observing name change and it's being updated accordingly, let alone others.
So it's not an ideal assumption that age and gender might have been changed in the process of changing name. Being said that, you should consider observing all of the properties one by one and bind actions differently and modify only the UI component that is mapped to that specific property.
Something like this:
override func viewDidLoad() {
...
NotificationCenter.default.addObserver(self,
selector: #selector(self.updateName),
name: Person.nameDidChange, object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(self.updateAge),
name: Person.ageDidChange, object: nil)
NotificationCenter.default.addObserver(self,
selector: #selector(self.updateGender),
name: Person.genderDidChange, object: nil)
...
}
#objc func updateName() {
nameLabel.text = person.name
}
#objc func updateAge() {
ageLabel.text = String(person.age)
}
#objc func updateGender() {
genderLabel.text = person.gender
}
I'm trying (unsuccessfully) to build a TreeController-controlled NSOutlineView. I've gone through a bunch of tutorials, but they all pre-load the data before starting anything, and this won't work for me.
I have a simple class for a device:
import Cocoa
class Device: NSObject {
let name : String
var children = [Service]()
var serviceNo = 1
var count = 0
init(name: String){
self.name = name
}
func addService(serviceName: String){
let serv = "\(serviceName) # \(serviceNo)"
children.append(Service(name: serv))
serviceNo += 1
count = children.count
}
func isLeaf() -> Bool {
return children.count < 1
}
}
I also have an even more simple class for the 'Service':
import Cocoa
class Service: NSObject {
let name: String
init(name: String){
self.name = name
}
}
Finally, I have the ViewController:
class ViewController: NSViewController {
var stepper = 0
dynamic var devices = [Device]()
override func viewDidLoad() {
super.viewDidLoad()
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func addDeviceAction(_ sender: Any) {
let str = "New Device #\(stepper)"
devices.append(Device(name: str))
stepper += 1
print("Added Device: \(devices[devices.count-1].name)")
}
#IBAction func addService(_ sender: Any) {
for i in 0..<devices.count {
devices[i].addService(serviceName: "New Service")
}
}
}
Obviously I have 2 buttons, one that adds a 'device' and one that adds a 'service' to each device.
What I can't make happen is any of this data show up in the NSOutlineView. I've set the TreeController's Object Controller Property to Mode: Class and Class: Device, and without setting the Children, Count, or Leaf properties I get (predictably):
2017-01-04 17:20:19.337129 OutlineTest[12550:1536405] Warning: [object class: Device] childrenKeyPath cannot be nil. To eliminate this log message, set the childrenKeyPath attribute in Interface Builder
If I then set the Children property to 'children' things go very bad:
2017-01-04 17:23:11.150627 OutlineTest[12695:1548039] [General] [ addObserver:forKeyPath:options:context:] is not supported. Key path: children
All I'm trying to do is set up the NSOutlineView to take input from the NSTreeController so that when a new 'Device' is added to the devices[] array, it shows up in the Outline View.
If anyone could point me in the right direction here I'd be most grateful.
Much gratitude to Warren for the hugely helpful work. I've got it (mostly) working. A couple of things that I also needed to do, in addition to Warren's suggestions:
Set the datastore for the Tree Controller
Bind the OutlineView to the TreeController
Bind the Column to the TreeController
Bind the TableView Cell to the Table Cell View (yes, really)
Once all that was done, I had to play around with the actual datastore a bit:
var name = "Bluetooth Devices Root"
var deviceStore = [Device]()
#IBOutlet var treeController: NSTreeController!
#IBOutlet weak var outlineView: NSOutlineView!
override func viewDidLoad() {
super.viewDidLoad()
deviceStore.append(Device(name: "Bluetooth Devices"))
self.treeController.content = self
}
override var representedObject: Any? {
didSet {
// Update the view, if already loaded.
}
}
#IBAction func addDeviceAction(_ sender: Any) {
if(deviceStore[0].name == "Bluetooth Devices"){
deviceStore.remove(at: 0)
}
Turns out the Root cannot be child-less at the beginning, at least as far as I can tell. Once I add a child, I can delete the place-holder value and the tree seems to work (mostly) as I want. One other thing is that I have to reload the data and redisplay the outline whenever the data changes:
outlineView.reloadData()
outlineView.setNeedsDisplay()
Without that, nothing. I still don't have the data updating correctly (see comments below Warren's answer) but I'm almost there.
To state the obvious, a NSTreeController manages a tree of objects all of which need to answer the following three questions/requests.
Are you a leaf i.e do you have no children? = leafKeyPath
If you are not a leaf, how many children do you have ? = countKeyPath
Give me your children! = childrenKeyPath
Its simple to set these up in IB or programatically. A fairly standard set of properties is respectively.
isLeaf
childCount
children
But its totally arbitrary and can be any set of properties that answer those questions.
I normally set up a protocol named something like TreeNode and make all my objects conform to it.
#objc protocol TreeNode:class {
var isLeaf:Bool { get }
var childCount:Int { get }
var children:[TreeNode] { get }
}
For your Device object you answer 2 out 3 question with isLeaf and children but don't answer the childCount question.
Your Device's children are Service objects and they answer none of that which is some of the reason why you are getting the exceptions.
So to fix up your code a possible solution is ...
The Service object
class Service: NSObject, TreeNode {
let name: String
init(name: String){
self.name = name
}
var isLeaf:Bool {
return true
}
var childCount:Int {
return 0
}
var children:[TreeNode] {
return []
}
}
The Device object
class Device: NSObject, TreeNode {
let name : String
var serviceStore = [Service]()
init(name: String){
self.name = name
}
var isLeaf:Bool {
return serviceStore.isEmpty
}
var childCount:Int {
return serviceStore.count
}
var children:[TreeNode] {
return serviceStore
}
}
And a horrible thing to do from a MVC perspective but convenient for this answer. The root object.
class ViewController: NSViewController, TreeNode {
var deviceStore = [Device]()
var name = "Henry" //whatever you want to name your root
var isLeaf:Bool {
return deviceStore.isEmpty
}
var childCount:Int {
return deviceStore.count
}
var children:[TreeNode] {
return deviceStore
}
}
So all you need to do is set the content of your treeController. Lets assume you have an IBOutlet to it in your ViewController.
class ViewController: NSViewController, TreeNode {
#IBOutlet var treeController:NSTreeController!
#IBOutlet var outlineView:NSOutlineView!
override func viewDidLoad() {
super.viewDidLoad()
treeController.content = self
}
Now each time you append a Device or add a Service just call reloadItem on the outlineView (that you also need an outlet to)
#IBAction func addDeviceAction(_ sender: Any) {
let str = "New Device #\(stepper)"
devices.append(Device(name: str))
stepper += 1
print("Added Device: \(devices[devices.count-1].name)")
outlineView.reloadItem(self, reloadChildren: true)
}
Thats the basics and should get you started but the docs for NSOutlineView & NSTreeController have a lot more info.
EDIT
In addition to the stuff above you need to bind your outline view to your tree controller.
First ensure your Outline View is in view mode.
Next bind the table column to arrangedObjects on the tree controller.
Last bind the text cell to the relevant key path. In your case it's name. objectValue is the reference to your object in the cell.
I would like to call a function which is coded on another class.
So far I have made a struct on the file structs.swift for my data:
struct defValues {
let defCityName: String
let loadImages: Bool
init(defCity: String, loadImgs: Bool){
self.defCityName = defCity
self.loadImages = loadImgs
}
}
I have made the file Defaults.swift containing:
import Foundation
class DefaultsSet {
let cityKey: String = "default_city"
let loadKey: String = "load_imgs"
func read() -> defValues {
let defaults = NSUserDefaults.standardUserDefaults()
if let name = defaults.stringForKey(cityKey){
print(name)
let valuesToReturn = defValues(defCity: name, loadImgs: true)
return valuesToReturn
}
else {
let valuesToReturn = defValues(defCity: "No default city set", loadImgs: true)
return valuesToReturn
}
}
func write(city: String, load: Bool){
let def = NSUserDefaults.standardUserDefaults()
def.setObject(city, forKey: cityKey)
def.setBool(load, forKey: loadKey)
}
}
in which I have the two functions read, write to read and write data with NSUsersDefault respectively.
On my main ViewController I can read data with:
let loadeddata: defValues = DefaultsSet().read()
if loadeddata.defCityName == "No default city set" {
defaultCity = "London"
}
else {
defaultCity = loadeddata.defCityName
defaultLoad = loadeddata.loadImages
}
But when I try to write data it gives me error. I use this code:
#IBOutlet var settingsTable: UITableView!
#IBOutlet var defaultCityName: UITextField!
#IBOutlet var loadImgs: UISwitch!
var switchState: Bool = true
#IBAction func switchChanged(sender: UISwitch) {
if sender.on{
switchState = true
print(switchState)
}else {
switchState = false
print(switchState)
}
}
#IBAction func saveSettings(sender: UIButton) {
DefaultsSet.write(defaultCityName.text, switchState)
}
You need an instance of the DefaultsSet class
In the view controller add this line on the class level
var setOfDefaults = DefaultsSet()
Then read
let loadeddata = setOfDefaults.read()
and write
setOfDefaults.write(defaultCityName.text, switchState)
The variable name setOfDefaults is on purpose to see the difference.
Or make the functions class functions and the variables static variables and call the functions on the class (without parentheses)
From the code you posted, it seems you either need to make the write method a class method (just prefix it with class) or you need to call it on an instance of DefaultsSet: DefaultsSet().write(defaultCityName.text, switchState).
Another issue I found is that you also need to unwrapp the value of the textField. Your write method takes as parameters a String and a Bool, but the value of defaultCityName.text is an optional, so String?. This results in a compiler error.
You can try something like this:
#IBAction func saveSettings(sender: UIButton) {
guard let text = defaultCityName.text else {
// the text is empty - nothing to save
return
}
DefaultsSet.write(text, switchState)
}
This code should now compile and let you call your method.
Let me know if it helped you solve the problem