I have Tap Bar Controller with 2 paths. One is settingController Other one is loginController and contactListController.
When i run the program the entry pint is set tocontactListControllerand if login is false apps shownloginController`. After login value is set on true and loginController is dismiss. On bottom i have Tab Bar Controller: ContactList | Settings
When i go to settings i have a LOGOUT button, i would like to do when i tap this how to set value login on false ? i have no segue between ContactList and SettingController
This is my ContactListController
class ContactsTableViewController: UITableViewController, SettingsControllerDelegate {
let settingsController: SettingsController = UIStoryboard(name: "Main", bundle: nil).instantiateViewControllerWithIdentifier("settingsController") as! SettingsController
override func viewDidLoad() {
super.viewDidLoad()
settingsController.delegate = self
}
func didLogoutSuccessfully() {
loggedIn = false
}
}
This is settings controller
protocol SettingsControllerDelegate {
func didLogoutSuccessfully()
}
class SettingsController: UITableViewController {
var delegate: SettingsControllerDelegate?
fun tapButton() {
self.delegate?.didLogoutSuccessfully() // Set login as false
}
if i added
override func viewDidLoad() {
super.viewDidLoad(
settingsController.delegate = self
presentViewController(settingsController, animated: true, completion: nil)
}
my controller setting is appear first. How can i change this value in other way?
UPDATE
in contact list i have
var loggedIn: Bool = false {
didSet {
if loggedIn == true {
self.configureView()
}
}
}
override func viewDidAppear(animated: Bool) {
if loggedIn == false {
performSegueWithIdentifier("showLogin", sender: nil)
}
//tableView.reloadData()
}
Consider either 1: using notifications (to which all interested controllers are registered as observers) to react to session state changes, 2: moving your session state to something "higher up the chain" (like in or "hanging off of" your app delegate), or 3: making a singleton session controller.
1 can be used with 2 and 3 and either 2 or 3 make accessing the current state from anywhere in your app easier. I'd go with a mix of 1 and 3 myself.
This approach in general relieves you from having to walk and inspect the controller hierarchy to find and set the same thig on all other controllers (which is icky because it's so tightly coupled; changing the hierarchy and/or reusing VCs elsewhere would probably break things).
You can pass data between the tabs using UITabViewControllers.viewControllers method which returns array of the view controllers in the tab
//in SettingsVC
func viewWillDisapear(){
//assuming its in the second index of tabBar
let contactVC = self.tabBarController.viewControllers[1] as ContactsTableViewController
contactVC.delegate = self
contactVC.loggedIn = true //or false as you wish
super.viewWillDisapear()
}
Related
Is there any equivalent in Swift to RACObserve(self, presentingViewController)?
Or any other why to imitate this behaviour?
My issue is that I want to be notified whenever a view controller is "hidden" by another view controller. In objc what I'd do is to check if self.presentingViewController is nil.
Note that in this scenario there's no knowledge of which view controller is presented, so it's impossible to notify from within its viewDidAppear/viewDidDisappear.
As I understand your question: you need to to know which view controller is presented now and you need notification inviewDidAppear/viewDidDisappear.
So we can get this in several way.
The simple way is:
Get information of which is the top ViewController right now.
2.Call this method in your viewDidAppear/viewDidDisappear
Like this :
Get Which is The Top ViewController
func getTopViewController() -> UIViewController? {
if var topVC = UIApplication.shared.keyWindow?.rootViewController {
while let presentedViewController = topVC.presentedViewController {
topVC = presentedViewController
return topVC
}
return topVC
}
return nil
}
Call in viewDidAppear:
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
if let top = getTopViewController() {
print("topView Controller name \(top.title)")
top.view.backgroundColor = .red
}
}
Hope it will help you !
I have a home UIViewController that contains a UITableView. On this view controller I display all games for the current user by reading the data from firebase in ViewWillAppear. From this view controller a user can press a button to start a new game and this button takes them to the next view controller to select settings, this then updates the data in firebase and adds a new child. Once they navigate back to the home view controller is there anyway to just update the data with the new child added instead of loading all the games for the table view again as I am currently doing?
This is my current code:
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if let currentUserID = Auth.auth().currentUser?.uid {
let gamesRef = Database.database().reference().child("games").child(currentUserID)
self.games = []
gamesRef.observeSingleEvent(of: .value, with: { snapshot in
for child in snapshot.children {
let game = child as! DataSnapshot
self.games.append(game)
self.tableView.reloadData()
}
})
}
}
I think you can use observeSingleEvent and .childAdded
You can do the loading of all the data in viewDidLoad and of single child in viewWillAppear since viewDidLoad will be called once initially
Since both methods will be called initially, so we can have a bool flag so we can control which code runs initially and which does not , since viewWillAppear is called after viewDidLoad so we change the value of this flag in viewWillAppear method and then control the execution of code inside viewWillAppear using this flag
class SomeVC: UIViewController {
var flag = false
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if flag {
//do your work here
}else {
flag = true
}
}
}
Edited:
Another solution can be that you dont do anything in viewDidLoad and do the work only in viewWillAppear since in this particular scenario data in both calls are related (fetching the data from Firebase)
class SomeVC: UIViewController {
var flag = false
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if flag {
//fetch only one child
}else {
//fetch all the data initially
flag = true
}
}
}
I am watching the video series
Swift Talk #5
Connecting View Controllers
url: https://talk.objc.io/episodes/S01E05-connecting-view-controllers
In this video series they remove all the prepareForSegue and use an App class to handle the connection between different view controllers.
I want to replicate this, but specifically only in my current view model; but what I don't get is how to connect view controllers through a view model (or even if you're meant to)
In their code, at github: https://github.com/objcio/S01E05-connecting-view-controllers/blob/master/Example/AppDelegate.swift
They use do this within their view controller
var didSelect: (Episode) -> () = { _ in }
This runs;
func showEpisode(episode: Episode) {
let detailVC = storyboard.instantiateViewControllerWithIdentifier("Detail") as! DetailViewController
detailVC.episode = episode
navigationController.pushViewController(detailVC, animated: true)
}
In the same way, I want to use my ViewController to use my ViewModel for a menu button press (relying on tag).
My code follows;
struct MainMenuViewModel {
enum MainMenuTag: Int {
case newGameTag = 0
}
func menuButtonPressed(tag: Int) {
guard let tagSelected = MainMenuTag.init(rawValue: tag) else {
return
}
switch tagSelected {
case .newGameTag:
print ("Pressed new game btn")
break
}
}
func menuBtnDidPress(tag: Int) {
print ("You pressed: \(tag)")
// Do a switch here
// Go to the next view controller? Should the view model even know about navigation controllers, pushing, etc?
}
}
class MainMenuViewController: UIViewController {
#IBOutlet var mainMenuBtnOutletCollection: [UIButton]!
var didSelect: (Int) -> () = { _ in }
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func mainMenuBtnPressed(_ sender: UIButton) {
let tag = (sender).tag
self.didSelect(tag)
}
}
What I don't understand is how do I connect the command
self.didSelect(tag)
to the function
func menuButtonPressed(tag: Int)
within my ViewModel
As I understand it, according to the swift talk video is that the idea is that the view controller are "plain" and that the view model handles all the major stuff, like menu button presses and then moving to different view controllers as necessary.
How do I connect the didSelect item to my viewModel function?
Thank you.
You should set didSelect property for your controller like here:
func showEpisode(episode: Episode) {
let detailVC = storyboard.instantiateViewControllerWithIdentifier("Detail") as! DetailViewController
detailVC.episode = episode
detailVC.didSelect = { episode in
// do whatever you need
// for example dismiss detailVC
self.navigationController.popViewController(animated: true)
// or call the model methods
self.model.menuButtonPressed(episode)
}
navigationController.pushViewController(detailVC, animated: true)
}
I am working on an iOS application that is built around a Tab View Controller. I have created a "Contacts" tab, where a user can find and select a contact from a list. When the user selects the contact, it takes the contact's name and passes it to a different tab. That function is being done like so:
func passName(name: String) {
let navTab = self.tabBarController!.viewControllers![2] as! UINavigationController
let homeTab = navTab.viewControllers[0] as! MainController
homeTab.passedName = name
tabBarController?.selectedIndex = 2
}
Everything works as it should so far (name is loaded into text field). My issue is that the value seems to keep coming back every time I change tabs and then go back to my Home tab. For example, if I select "John" from my contacts, it will take me to the Home Tab and put John's name in a textfield. Let's say I delete the last two letters of the name, so now it is "Jo". If I load a different tab and come back, the name field has been reset to "John". It's as if the value gets re-passed every time I open the Home Tab. Also, every time I load the Home Tab after passing a name, my console prints: "Name Passed: John", so it shows that this is being processed every single time the tab appears. Here is my code for processing the name:
var passedName: String!
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
//Checks if name was passed to controller
if let validName = passedName {
print("Name passed: \(validName)")
nameTextField.text = validName
}
}
Am I passing the data incorrectly? I was thinking it might be because I have the above code being called in the viewWillAppear method, but that doesn't make sense, as essentially the data is only being passed one time from the Contacts tab. Thanks!
The problem is that you're not actually passing the value back to the original view. Apple's recommendation for passing information between classes is to use the delegate pattern. This allows the modal view to call the delegate class's function, which changes the name local to the original view because that function is declared in the original view's viewController. You can read more about the pattern in this tutorial, but I've also included a brief example relevant to your use case below.
mainViewController:
class namesTableViewController: UITableViewController, editNameDetailsViewControllerDelegate {
var name : String
#IBAction func editButtonPressed(_ sender: UIBarButtonItem) {
performSegue(withIdentifier: "editPerson", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "editPerson" { //Modal segue
let navController = segue.destination as! UINavigationController
let controller = navController.topViewController as! editNameViewController
controller.delegate = self
if let person = sender as? Person {
print("Sending person to edit")
controller.personToEdit = person
}
} else {
super.prepare(for: segue, sender: sender)
}
}
//Protocol function
func changeName(n: String, controller: UIViewController) {
name = n
dismiss(animated: true, completion: nil)
}
}
editNameViewController:
class editNameViewController: UIViewController {
#IBOutlet weak var personNameTextField: UITextField!
var personToEdit : Person?
weak var delegate : PersonTableViewController?
override func viewDidLoad() {
super.viewDidLoad()
if personToEdit != nil {
personNameTextField.text = personToEdit?.name
}
}
// Button Actions
#IBAction func saveButtonPressed(_ sender: UIBarButtonItem) {
delegate?.personDetailsView(n: personNameTextField.text, controller: self)
}
}
Finally, the protocol class :
protocol editNameDetailsViewControllerDelegate : class {
func personDetailsView(n: String, controller: UIViewController)
}
Hope this helps.
The problem is "passedName" variable doesn't changed its value every time you edit it in your UITextField. Keep in mind that every time you change tabs, the UIViewController will call viewWillAppear and viewDidAppear. So your UITextField will always show passedName value once you select other tab and return.
I suggest that every time you edit the textfield you should update passedName value.
Sorry for my bad english.
Is it possible to switch to another view controller only by turning the device to left/right?
I would try it with:
//LandscapeTabView
override func viewWillLayoutSubviews() {
if UIDevice.current.orientation == UIDeviceOrientation.landscapeLeft || UIDevice.current.orientation == UIDeviceOrientation.landscapeRight {
}
else {
}
But don't know what to fill in that function?
Thanks for helping a rookie!
First: you can subscribe to system notification about device rotating like this
NotificationCenter.default.addObserver(self, selector: #selector(self.orientationChanged), name: NSNotification.Name.UIDeviceOrientationDidChange, object: nil)
Then make function
func orientationChanged() {}
For correct state determining I recommend using this method
UIApplication.shared.statusBarOrientation == .portrait
If its true - portrait, false - landscape
So, depended on state, for example, you can push some vc on landscape and pop it when device is turned back.
For pushing you can easily create an instance of your ViewController like that
let vc = self.storyboard?.instantiateViewControllerWithIdentifier("here_is_vc_id") as! YourViewController
And for pop:
_ = navigationController.pushViewController(vc, animated: true)
Notice: VC you're instantiating must be store at one (and main) storyboard. Also you need to set up an is (where the string "here_is_vc_id" goes) in Identity Inspector in "Storyboard ID" field.
Here you go :)
Try my little effort-
func rotated()
{
if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
{
print("landscapeMode")
let nextView = self.storyboard?.instantiateViewControllerWithIdentifier("HomeWorkViewController") as! HomeWorkViewController
self.navigationController?.pushViewController(nextView, animated: true)
}
if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
{
print("PortraitMode")
//As you like
}
}
The approaches suggested are valid but the recommended way to react to this kind of changes is using UIContentContainer protocol (iOS8+).
Then you can add a child view controller to your controller and control how it should animate. You can use this as a reference: Implementing a Container View Controller.
override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
super.viewWillTransitionToSize(size, withTransitionCoordinator: coordinator)
let isPortrait = size == UIScreen.mainScreen().fixedCoordinateSpace.bounds.size
// Add a child view controller if landscape, remove it if portrait...
}