How do I make my app go to a view when it detects that it enters the background? I have an authentication screen and I want that the user has to authenticate again when he comes back to the app. (Something like in 1password)
I tried to do something in appDelegate, but I just got a lot of errors.
let mapViewControllerObejct = self.storyboard?.instantiateViewControllerWithIdentifier("MainVC") as? MainVC
self.navigationController?.pushViewController(mapViewControllerObejct!, animated: false)
This is what I have tried to implement in applicationWillResignActive, but I got the error that appDelegate has no member called storyboard.
Thanks for the help
You can move to rootview controller and write this code in this function:
func applicationWillEnterForeground(application: UIApplication) {
if let navigationController = window?.rootViewController as?UINavigationController {
navigationController.popToRootViewControllerAnimated(false)
}
}
Related
now I am developing messenger
MessengerBox is tableViewController, when user tap the one of the cell, then chatRoomViewcontroller is presented.
if the app is not running and message arrived, then push notifications show. And user Tap the notification, App shows chatRoomViewcontroller directly.
Initially, I implemented this code by using window.rootViewController
But the problem happened. when I tap Back Button of chatRoomviewController, change is not happened because this view controller is rootview and its presentingViewController is empty!
so I fixed it like below
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
///some code for notification..
let mVC //this is MessengerBoxViewcontroller
let crVC //this is ChatRoomViewController
CRVC?.sender = "asdf"
do{
self.window?.rootViewController = mVC
self.window?.makeKeyAndVisible()
defer{
mVC?.presentChatRoomVC()
}
}
/// some code...
}
It works! But I'd like to know better way.
And Also I think I should study How window and viewcontrollers works.
please recommend me the better way, and reference documents.
Thank you.
You need to handle back button action programatically in ChatRoomViewControllerto solve your problem :
On back button Click :
Check for MessengerBoxViewcontroller is present in navigationController stack.
if MessengerBoxViewcontroller is in navigationController stack then pop to move back to MessengerBoxViewcontroller.
Else present MessengerBoxViewcontroller.
if let viewControllers = self.navigationController?.viewControllers {
for viewController in viewControllers {
if viewController.isKindOfClass(MessengerBoxViewcontroller) {
print("Your controller exist")
navigationController?.popViewController(animated: true)
}
}
}
else {
let vc = self.storyboard?.instantiateViewController(withIdentifier: "messengerBoxViewcontroller") as! MessengerBoxViewcontroller
self.present(vc, animated: true, completion: nil)
}
I am currently making a small login app using Firebase. I am currently having problems with my login page.
When my users already are logged in, when they open the app, I want to change the initial view controller, so that the user can go straight to the homepage.
So my question is, what line of code do I have to perform in order to do this?
override func viewDidLoad() {
super.viewDidLoad()
if FIRAuth.auth() ? .currentUser ? .uid == nil {
notLoggedIn()
}
}
func notLoggedIn() {
let storyBoard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "Startpage") as!ViewController
self.present(nextViewController, animated: true, completion: nil)
}
There's a couple of ways you can do this. If you really want to change the initial view controller, you would want to NOT set an initial view controller in your storyboard, then in your app delegate's application(_:didFinishLaunchingWithOptions:) implementation, you would create a new Window object and set whichever view controller on it you want to present as the rootViewController. Then, you would call makeKeyAndVisible on that window object. Note that if you do it this way, you'll have to separately handle the case when they log out if you want to display your login window again. In that case you would just do the same thing again: make a new window object with your new ViewController object as the rootViewController and present it.
Another option is to check if they are logged in in your initial view controller's viewDidLoad method and then present your login screen if they aren't. This is what I do in one of applications where the app needs some data, either by logging into an account or manually adding it, before it can do anything.
EDIT:
Here's what my viewDidLoad, etc. looks like (note that mine project is in Objective-C, so I'm just kinda guessing without actually testing it what the correct Swift syntax is. You might need to make some adjustments) You have to dispatch the present call to the main queue because in viewDidLoad you (probably) don't have everything in order yet to actually present a new view controller (I did this quite a long time ago, so I don't recall exactly why it has to be dispatched, but because of the fact that we're already in the process of presenting the current view controller, it makes sense that you wouldn't be able to present another one at the same time. Maybe someone else can weigh in on this, because I really don't remember anymore.):
override func viewDidLoad() {
super.viewDidLoad()
if (!userLoggedIn) {
showLoginScreen()
}
}
func showLoginScreen() {
let loginViewController = storyboard?.instantiateViewController(withIdentifier: "Startpage") as! ViewController
DispatchQueue.main.async {
present(loginViewController, animated: true, completion: nil)
}
}
You can use this line of codes.
Keep in mind that you should add storyboard reference with identifier
named respectively for your need - goToLogin - in my case.
Hope It'll be helpful for anyone.
override func viewDidLoad() {
super.viewDidLoad()
Auth.auth().addStateDidChangeListener { auth, user in
if let user = user {
// User is signed in.
print("user signed in")
//Add the rest of the code here because after passig the caluses
// viewdidload will call another funxtions to it can crash
} else {
// User not signed in
self.performSegue(withIdentifier: "goToLogin", sender: Any?.self)
}
}
}
I have 5 viewControllers(A,B,C,D,E), all these viewControllers are programmatically connected, and i could push and pop between them successfully.
Using:
navigationController?.pushViewController(loginVc, animated: true)
_ = navigationController?.popViewController(animated: true)
NOTE: ViewController A appears first as a default initial viewController.
Now, what i want is, when the user installs the App, only for the first time the viewController A must be shown as the initial viewController, rest of the times when the App is opened, the viewController D must be the initial viewController and from there i should be able to jump between previous viewControllers. How can i implement this. Im using Xcode 8.2, Swift 3.0
Thanks in advance.
In order to do that, you simply could add a boolean to your NSUserDefaults, using the following code:
let defaults = UserDefaults.standard
if (!defaults.bool(forKey: "firstTime")) { //will be false if does not exist yet
navigationController?.pushViewController(yourDesiredVC, animated: true) //push desired vc
defaults.set(true, forKey: "firstTime") //set the key so it never executes again
} else {
navigationController?.pushViewController(yourDesiredVC, animated: true) //push the other vc
}
Your question doesn't really say very much without some code, but one suggestion (given the current quality of the question) would be to use UserDefaults. Add your current version of the app to a key called e.g. LatestVersion. Compare it at launch with the apps current version, if they don't match, show ViewControllerA, if not show ViewControllerB.
Another way is just saving launchedForFirstTime. If its not set show ViewControllerA, however the above would take in account future versions of the app where you might want to show that view as well.
You can keep a value in UserDefaults to keep track of the returning users and check if it's there:
if let returning :Bool = UserDefaults.standard.bool(forKey: "initial_controller_shown") {
//returning user flow
} else {
//new user flow
}
A common place to check for this is in the applicationDidBecomeActive or didFinishLaunchingWithOptions
when first time your app launched then use a flag and store some value in it so that next time when your app run then you can check that whether user visit the app for the first time or not .. Now after that go to appDelegate and paste the following code in DidFinishLaunchingWithOption...
if yourFlag == true
{
let mainStoryboard: UIStoryboard = UIStoryboard(name: "MainStoreyBoard", bundle: nil)
let controller = mainStoryboard.instantiateViewController(withIdentifier: "StoreyBoardIdofYourViewController") as! UINavigationController
self.window?.rootViewController = controller
}
This will launch D viewcontroller .....
You can check it in your app delegate.m file whether the app installed first time ViewController A will appear as a initial view controller else view controller D. Check it in the following function:
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
//check the initial view controller here//
return true
}
Swift 3:
let launchBefore = UserDefaults.standard.bool(forKey: "launchBefore")
if launchBefore {
print("Not first launch.") } else {
print("First launch, setting UserDefault.")
UserDefaults.standard.set(true, forKey: "launchBefore") }
You are using one Navigation Controller so it will be hard to implement your behavior. It will be much easier for you to use separate View Controllers for View A and D and call them using:
present(vc, animated: true)
and dismiss calling:
dismiss(animated: true)
I want a way for the user to have a welcome screen / tutorial on the first launch of the app. If it isn't the first launch of the app, then it open as it usually would.
I already have the welcome screen tied to a button function if the app opens normally. I'm using BWWalkThroughViewController. Here's my code for the button function:
#IBAction func showWalkThroughButtonPressed() {
// Get view controllers and build the walkthrough
let stb = UIStoryboard(name: "MainStoryboard", bundle: nil)
let walkthrough = stb.instantiateViewControllerWithIdentifier("walk0") as! BWWalkthroughViewController
let page_one = stb.instantiateViewControllerWithIdentifier("walk1") as UIViewController
let page_two = stb.instantiateViewControllerWithIdentifier("walk2") as UIViewController
let page_three = stb.instantiateViewControllerWithIdentifier("walk3") as UIViewController
let page_four = stb.instantiateViewControllerWithIdentifier("walk4") as UIViewController
let page_five = stb.instantiateViewControllerWithIdentifier("walk5") as UIViewController
// Attach the pages to the master
walkthrough.delegate = self
walkthrough.addViewController(page_one)
walkthrough.addViewController(page_two)
walkthrough.addViewController(page_three)
walkthrough.addViewController(page_four)
walkthrough.addViewController(page_five)
self.presentViewController(walkthrough, animated: true, completion: nil)
}
func walkthroughCloseButtonPressed() {
self.dismissViewControllerAnimated(true, completion: nil)
}
That code is located in the MyTableViewController.swift file.
Here's what I can't figure out:
I want the view controllers to show on first launch. Once the user finishes the tutorial, they can press the Close button and it will close. I have the code to check if it's the app's first launch. It's located in the AppDelegate.swift file. Here's that code:
// First Launch Check
let notFirstLaunch = NSUserDefaults.standardUserDefaults().boolForKey("FirstLaunch")
if notFirstLaunch {
print("First launch, setting NSUserDefault")
NSUserDefaults.standardUserDefaults().setBool(true, forKey: "FirstLaunch")
}
else {
print("Not first launch.")
}
return true
So how do I get the welcome screen to launch on first launch? Do I have to create a function in AppDelegate to handle that, and if so what do I have to do to make the tutorial the initial view controller for just the first launch?
I believe what you need to do is already covered here: Programmatically set the initial view controller using Storyboards. If that doesn't work for you add more notes on why the implementation failed. A google search on "programatically change uiviewcontroller on launch ios" will yield other similar links.
I have created an app that uses storyboard and have successfully created a tableview and detail page which all works.
I would like it so that users swiping the localNotifications can be sent to the correct detail page within the app.
It appears that I can call functions from the ViewController but whenever they refer to themselves to update any details or perform a segue the app crashes.
The code i have in my ViewController is as follows:
func handleMessageNotification (messageID:String)
{
// this function should act as a conduit for the call from the delegate
println("notif messageID: \(messageID)");
self.performSegueWithIdentifier("showMessageDetail", sender: self);
self.messageView.reloadData();
}
and this is called from my appDelegate
func application(application: UIApplication, didReceiveLocalNotification notification: UILocalNotification) {
if (application.applicationState == UIApplicationState.Background || application.applicationState == UIApplicationState.Inactive)
{
var rootViewController = self.window!.rootViewController
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
var setViewController = mainStoryboard.instantiateViewControllerWithIdentifier("ViewController") as ViewController
rootViewController?.navigationController?.popToViewController(setViewController, animated: false)
setViewController.handleMessageNotification(messageID);
}
}
the println works correctly but performSegue fails (fatal error: unexpectedly found nil while unwrapping an Optional value) and the messageView.reload() fails (same error).
How do I get a notification to fire the app to the correct place upon opening?
This solution 'Get Instance Of ViewController From AppDelegate In Swift' uses much of the same but mine will not allow access to anything with the ViewController.
======= Update - Solution =======
For anyone else with this issue. Following on from what Gabuh had suggested below; the full solution for me was to do the following:
func application(application: UIApplication, didReceiveLocalNotification notification: UILocalNotification) {
if (application.applicationState == UIApplicationState.Background || application.applicationState == UIApplicationState.Inactive)
{
let navigationController = application.windows[0].rootViewController as UINavigationController;
navigationController.popToRootViewControllerAnimated(false); // I need to push back to root before performing segue
let rootViewController = navigationController.visibleViewController;
rootViewController.performSegueWithIdentifier("showMessageDetail", sender: self);
}
}
this also allows me to make calls on functions in the view such as in the original example e.g.
rootViewController.handleMessageNotificaion(messageID);
or
rootViewController.messageView.reloadData();
You are creating an instance of a new ViewController. And you are trying to call a function on that ViewController, that is trying to perform a segue, when the ViewController is not even displayed. I think that's not going to work...
If you want to perform a segue from your detail view, you have to access to the current instantiated view Controller and perform the segue from it.
If you want to know how to get the instance of the UIViewController that is being displayed, in this post there are several ways that show you how to do it:
Get the current view controller from the app delegate
In pseudo-code, in your appDelegate:
1- get current UIViewController instance (not new one)
2- perfom segue from that view controller (or present modally or whatever transition you want)
In Swift 3:
guard let rvc = self.window?.rootViewController as? VCName else { return }
rvc.methodInYourVC()
The above assumes
That you don't want to create a whole new instance of VCName, just want a reference to it
That you know the VC you want to reference is your root VC