I'am new to ios. I have several view controllers and I want back button to get user to level up controller. Example.
But if user comes from gameOver view, back button sent him back to gameOver and I don't want such behavior (I want user to be sent at second level (games level) controller as shown). On android I could set the pop behavior for the navigation actions with mouse very easily.
What is the correct way to do the same in ios? Or I have to create the custom back button and do everything manually?
Using Swift this can be achieved using below code:
func popToViewController(_ specificViewController: Swift.AnyClass) {
let viewControllers = self.navigationController!.viewControllers
for eachViewController in viewControllers {
if eachViewController.isKind(of: specificViewController) {
self.navigationController!.popToViewController(eachViewController, animated: true)
break;
}
}
}
Usage:
self.popToViewController(gameLevelViewController.self)
Related
I am very much new to swift and ios so i need my doubts to be cleared for the below concept
I have created a view with a button having background image of back arrow and on button action i am going back to the previous controller which is the Login, is it safe to do it this way instead of using NavigationController??
#IBAction func onBackPressed(sender: AnyObject) {
let aaa : Login =
self.storyboard?.instantiateViewControllerWithIdentifier("Login")
as! Login
self.presentViewController(aaa, animated: true, completion: nil)
}
Thanks
Navigation controller is best when you want to push to next View Controller.
(i.e) Navigation Controller ->View Controller ->View Controller[for Push].
So my suggestion is if you want to come back to previous view controller use Navigation Controller
When you want to present a new View Controller that time no need.
I'm creating a simple game with a pause button. I want to show another view controller with the pause screen without resetting the game view controller when i return. Every thing i have tried, has resulted in the game view controller being reset, when i press the resume button and return to the game.
Does anybody know how i can do this without resetting the game?
It's a sprite kit and swift iOS app in xcode.
You can show a pop-up based view. You can create .xib and design your pause view as you wish. Then you can resume the game without resetting anything.
Sample code:
// Set Pause Page
var pauseView = PauseView.loadFromNib() // need an extension
#IBAction func Pause(sender: UIButton) {
pauseView.btnResume.addTarget(self, action: #selector(resume(_:)), forControlEvents: .TouchUpInside)
// set place on view
view.addSubview(pauseView)
}
func resume(sender:UIButton) {
pauseView.removeFromSuperview()
}
I created a demo for you:
Full demo available on Github: Get Source Code
Create a variable in your original view controller:
var shouldReset = true
Then, when you perform a segue back, add this in your prepareForSegue:
let vc = destination as! //Your view controller
vc.shouldReset = false
In your viewDidLoad (or wherever you reset your data):
if shouldReset == true {
//Reset
}
I have an app that doesn't have to show any tab when the user isn't logged in. I'm facing many issues with this functionality. First of all, I had embed the views, after the login screen, into a tab bar controller and everything was showing ok, except when I had implemented the login feature. As it's an async call, I had to wait until the credentials were validated. I wasn't able to do this in the shouldPerformSegue method or any other method provided by apple because you can't block the main thread until the async stuff is done, so the segue has to be done programaticaly in an IbAction:
#IBAction func doLogin(sender: AnyObject) {
userIsLogged = false
let apiCall = webApi()
apiCall.callCheckIsUserLogged(nil, password : self.passwordField.text, email: self.mailField.text){ (ok) in
if ok {
if(userIsLogged == true){
dispatch_async(dispatch_get_main_queue()) {
self.performSegueWithIdentifier("loginUser", sender: self)
}
}else {
NSOperationQueue.mainQueue().addOperationWithBlock{
print("User not logged in")
self.alert.message = "Please enter valid credentials"
self.displayAlert()
}
}
}
}
}
But this has driven me to another issue: after the programatic segue, my tab bar controller was disappearing, and after read a while it looks like the only way to avoid this is to embed your tab bar controller into a navigation controller. So I did it, but now, I got many new issues. First of all I got two navigation controllers, the one who is at the very beginning of the project and this new one I have embed into the tab bar controller. A picture will illustrate this better than my words:
Now I have two navigation controllers, and I don't know how to hide the top one. Already tried:
self.navigationController?.navigationItem.hidesBackButton = true
But is hiding the arrow and I need to hide the other one navigation controller. But the best thing indeed would be to see the best approach for this kind of cases, when you want to add a tabBar controller embed into a navigation controller in the middle of the project.
Thanks all
I guess you can take another approach. Make login storyline and your app storyline distinct.
Have a storyboard for your login procedure, and another storyboard for your home (or whatever you like) and manage them in AppDelegate.
This is how i did it:
if /* user must log in */ {
self.window?.rootViewController = loginStoryboard?.instantiateInitialViewController()
self.window?.makeKeyAndVisible()
}
else {
self.window?.rootViewController = homeStoryboard?instantiateInitialViewController()
self.window?.makeKeyAndVisible()
}
Put this code in a method (for example called manageRootViewController()) and call it at app launch, or after your login. (You can also add custom animations if you like)
I'm working in an app that logs in an user if there isn't another user already logged in at launch time. This way the first view to appear should be the Login View. But in the case there is a logged user already, the first view appearing should be the main menu. Im handling this with the viewWillAppear function and it's working, but I don't know if this is the correct approach or how it should be handle in this situations.
Here is my code. My first view is MainMenuVC in which I control if there is a logged user or not, then I choose if stay in main menu view or push my login view.
class MainMenuVC: UIViewController {
override func viewWillAppear(animated: Bool) {
if (UserMgr.users.count == 0){
var vc1:LoginVC = self.storyboard?.instantiateViewControllerWithIdentifier("LoginView") as LoginVC
self.navigationController?.pushViewController(vc1, animated: false)
}
else
{
//I do nothing so this view is loaded
}
}
I don't know if i should use another ViewController and implement the function loadView() to decide what view load, but the problem is make that view work with the story board and my navigation controller.
Any suggestions?
Basically you will have two different view controllers, one for the login screen (VCLogin) and one for the main menu (VCMainMenu). Now, in your AppDelegate there are methods which are called, when the app launches respectively when it appears. So, place the code checking whether a user is logged in there and make the appropriate view controller the root view controller, e.g.
let navigationController = window.rootViewController as UINavigationController
navigationController.rootViewController =
userIsLoggedIn ? mainMenuViewController : loginViewController
I have a settings screen, in that I have a table cell. By clicking on that I take to another screen where user can choose an option and I want it back in the previous view controller when back button is pressed.
I can put a custom bar button item, but I want to return to the parent view controller using the back button in the navigation bar rather than with a custom button on the view.
I don't seem to be able to override the navigation back button to point it down to my unwind segue action and since the back button doesn't appear on the storyboard, I cant drag the green Exit button to it
Is it possible to unwind a push segue with the back button?
Here's my solution, based on Objective-C code from Blankarsch to this StackOverflow question: How to trap the back button event
Put this code inside the View Controller you want to trap the Back button call from:
override func didMoveToParentViewController(parent: UIViewController?) {
if (!(parent?.isEqual(self.parentViewController) ?? false)) {
println("Back Button Pressed!")
}
}
Inside of the if block, handle whatever you need to pass back. You'll also need to have a reference back to calling view controller as at this point most likely both parent and self.parentViewController are nil, so you can't navigate the View Controller tree.
Also, you might be able to get away with simply checking parent for nil as I haven't found a case where pressing the back button didn't result in parent being nil. So something like this is a bit more concise:
override func didMoveToParentViewController(parent: UIViewController?) {
if (parent == nil) {
println("Back Button Pressed!")
}
}
But I can't guarantee that will work every time.
Do the following in the view controller that has the back button
Swift 3
override func didMove(toParentViewController parent: UIViewController?) {
if !(parent?.isEqual(self.parent) ?? false) {
print("Parent view loaded")
}
super.didMove(toParentViewController: parent)
}
I tried the same and it seems that you cannot catch the standard back button's action so the solution will be to use a custom button and bind it to a segue which leads back to the previous page.
You could use some sort of delegation as you did or use a custom back button and an unwind segue.
Better even, you could handle passing data between your view controllers using a mediator:
http://cocoapatterns.com/passing-data-between-view-controllers/