How to change Labels and Table View from another Class? - swift

Question

I made an application, this application have a couple of functions. It has Table View, Labels, Buttons etc. I made a Picker View in a class called SettingsViewController that is useful for choosing language. I made it and it's working good but I don't know how to change text of Table View and Labels of other classes. I'm not to experienced in calling classes.
This is my class SettingsViewController:
import Foundation
import UIKit
class SettingsViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var languages = ["English", "German", "French"]
var selectedLanguage = 0
#IBOutlet var languageLabel: UILabel!
#IBOutlet var topPartView: UIView!
#IBOutlet weak var languagePicker: UIPickerView!
#IBOutlet var SubmitLanguageButton: UIButton!
#IBAction func pickLanguageButton(sender: AnyObject) {
//Show Picker
topPartView.hidden = false
languagePicker.hidden = false
SubmitLanguageButton.hidden = false
}
#IBAction func submitLanguageButton(sender: AnyObject) {
//Hidde Picker
topPartView.hidden = true
languagePicker.hidden = true
SubmitLanguageButton.hidden = true
if (selectedLanguage == 0) {
languageLabel.text = "English"
}
else if (selectedLanguage == 1) {
languageLabel.text = "German"
}
else if (selectedLanguage == 2) {
languageLabel.text = "French"
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
topPartView.hidden = true
languagePicker.hidden = true
SubmitLanguageButton.hidden = true
languagePicker.delegate = self
languagePicker.dataSource = self
}
func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return languages[row]
}
func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return languages.count
}
// returns the number of 'columns' to display.
public func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
selectedLanguage = row
}
}
Another random ViewController with Table View and Label:
import UIKit
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
let foodList:[String] = ["Apple", "Bread", "Phineapple", "Water", "Other"]
#IBOutlet weak var myTableView: UITableView!
#IBOutlet var foodTitleLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
foodTitleLabel.text = "Food"
myTableView.reloadData()
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
var returnValue = 0
return returnValue
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let myCell = tableView.dequeueReusableCellWithIdentifier("myCells", forIndexPath: indexPath)
myCell.textLabel!.text = foodList[indexPath.row]
myCell.textLabel!.numberOfLines = 0
return myCell
}
}
So how I'm gonna change Labels and Table View from another class, because every text have to be on language that is chose in SettingsViewController ?
For ex: When user choose English, the text in all ViewControllers have to be in English.
When user choose French, the text in all ViewControllers have to be in French.
If this question was not clear, please inform me, I wil try to show more info. Thanks for your contribution.

Answer 1

We can accomplish this in a cleaner way with less code like :
enum names{
case English, German, French
func food() -> String {
switch self {
case English: return "food"
case German: return "Lebensmittel"
case French: return "Aliments"
}
}
func foodList() -> [] {
switch self {
case English: return ["Apple", "Bread", "Pineapple", "Water", "Other"]
case German: return [ "Apfel", "Brot", "Pineapple", "Wasser","Andere"]
case French: return ["Pomme", "Pain", "Ananas", "Eau", "Autre"]
}
}
}
import UIKit
var lang = names.English
class SettingsViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
foodTitleLabel.text = lang.food()
foodList = lang.foodList()

Answer 2

So you could address by different approachs the problem, but for my point of view the easiest one is to implement a protocol that handles events in a viewcontroller and has an impact in another one for examlple
protocol ChangeLanguagesProtocol
{
func returnNewLanguages(newlanguages:[String])
}
then you you will need to implement the protocol and its method in your viewcontroller like
class SettingsViewController: UIViewController,
UIPickerViewDelegate, UIPickerViewDataSource , ChangeLanguagesProtocol {
var languages = ["English", "German", "French"]
func returnNewLanguages(newlanguages:[String]){
self.languages = newlanguages
}
Then in you second ViewController class you need to have a var of the type of your protocol and trigger its method when your need it
//variable
var delegate:ChangeLanguagesProtocol!
//for example when clicking a button
#IBAction func SampleButtonPress(sender:UIButton){
let newlanguages:[String] = ["Spanish", "Chinesse", "German", "French", "Other"]
delegate.returnNewLanguages(newlanguages)
}
last step we need to assign the delegate variable when we are going to push to the desired viewcontroller, in the case where viewcontrollers are not next to each other you can use singleton or a shared instance to maintain your delegate property until you need it, but it will look something like
// this should be in your first ViewController
#IBAction func gotoNextViewController(sender:UIButton){
let _localization = Localization(nibName: "Localization", bundle:nil)
_localization .delegate = self
self.navigationController?.pushViewController(_localization , animated: true)
}

Answer 3

You are trying to internationalize your app. Apple has some built in stuff for this that you should check out: https://developer.apple.com/internationalization/
If that doesn't suit your needs, to answer your question, your views should set their text when they either load (viewDidLoad) or right before they appear (viewWillAppear) as a result of the user's language choice, which could possibly be stored in NSUserDefaults. Your settings class shouldn't have to force any change in other views, your other views should set their own text to the right language before they are displayed.
struct Localization {
static func stringsForScreen(screenName:String, forLanguage language:String) -> [String:String] {
//parse a file that has the strings for the given screen in the given language, and return it
}
}
class HomeViewController:UIViewController {
#IBOutlet var titleLabel:UILabel?
#IBOutlet var bodyLabel:UILabel?
override func viewDidLoad() { //or possibly viewDidAppear, depends on your needs
super.viewDidLoad()
let language = NSUserDefaults.standardUserDefaults().stringForKey("currentLanguage") ?? "English"
let textDict = Localization.stringsForScreen("HomeViewController" forLanguage:language)
titleLabel.text = textDict["titleLabelText"] ?? ""
bodyLabel.text = textDict["bodyLabelText"] ?? ""
}
}
class PickLanguageViewController:UIViewController, UIPickerViewDelegate {
var languages = ["English","French","Spanish"]
//Whatever method the picker uses
func pickerView(pickerView:UIPickerView didSelectRow row:Int inComponent component:Int) {
NSUserDefaults.standardUserDefaults().setObject(languages[row] forKey:"currentLanguage")
}
}
skeleton example of how this might be structured.

Answer 4

I found solution. First of All the variable selectedLanguage I declared it out of the class SettingsViewController.
import UIKit
var selectedLanguage = 0 //<<< Here
class SettingsViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var languages = ["English", "German", "French"]
After that I did this in method viewDidLoad to every ViewController (I will show just one ViewController).
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
if (selectedLanguage == 0) { //English
foodTitleLabel.text = "Food"
foodList = ["Apple", "Bread", "Pineapple", "Water", "Other"]
}
else if (selectedLanguage == 1) { //German
foodTitleLabel.text = "Lebensmittel"
foodList = [ "Apfel", "Brot", "Pineapple", "Wasser","Andere"]
}
if (selectedLanguage == 2) { //French
foodTitleLabel.text = "Aliments"
foodList = ["Pomme", "Pain", "Ananas", "Eau", "Autre"]
}
I hope this will be helpful for other users, because It worked perfectly for me.