i'm trying to make a action in other storyboard but i'm getting this error
2019-12-24 07:44:32.861248-0800 test[1588:142069] [LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x600003631e50 UIView:0x7fc09d715410.width == - 16 (active)>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x600003631e50 UIView:0x7fc09d715410.width == - 16 (active)>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in
<UIKitCore/UIView.h> may also be helpful.
i'm new in ios development, i know that other request are posted in stack overflow but i'm don't understand how to revolve my problem.
i create un Alert.storyboard with nothing
AlertViewController.swift with :
import UIKit
class AlertViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func viewDidAppear(_ animated: Bool) {
a()
}
func a() {
let alert = UIAlertController(title: "Something", message: nil, preferredStyle: .actionSheet)
let opt1 = UIAlertAction( title: "Action 1", style: .default) { (action) in
print("dskhgohg")
self.dismiss(animated: true)
}
alert.addAction(opt1)
present( alert, animated: true, completion: nil )
}
}
AlertService.swift
import UIKit
class AlertService {
func alert() -> AlertViewController {
let storyboard = UIStoryboard(name: "Alert", bundle: .main)
let alertVC = storyboard.instantiateViewController(identifier: "AlertVC") as! AlertViewController
return alertVC
}
}
and i added a button in Main.storyboard with action in viewController
let alertService = AlertService()
#IBAction func btn() {
let alertVC = alertService.alert()
present(alertVC, animated: true)
print("dsgjodig")
}
maybe i shoud not action sheet in viewDidAppear
All action sheets do that. It’s an Apple bug. It has no effect on your app’s functionality. Ignore it and move on.
Related
So my goal for now is to successfully keep users logged in and show a certain viewController depending if they're logged in or not. I've read a lot of the Stack questions that showed up first on Google searches about this same topic and they said use addStateDidChangeListener() and that's exactly what I did.
I didn't know how to approach this, so I watched a Youtube video and copied the exact code the guy had, his project did what I wanted mine to do, so I gave it a shot. Unfortunately when I run the simulator, sign in, exit the simulator and simulate again, nothing changes. I will add my code and it's location.
This is the code in my AppDelegate.swift in the didFinishLaunchingWithOptions method
let storyboard = UIStoryboard.init(name: "Main", bundle: Bundle.main)
let auth = Auth.auth()
auth.addStateDidChangeListener { (_, user) in
switch user {
case nil:
guard self.activeViewController! is StudentSegmentedTableViewController else { return }
let nonLoggedInViewController = storyboard.instantiateViewController(withIdentifier: Constants.StoryboardIDs.GothereMainMenuStoryboardID) as! GothereMainMenuViewController
self.navigationController.setViewControllers([nonLoggedInViewController], animated: false)
self.navigationController.popToViewController(nonLoggedInViewController, animated: true)
self.activeViewController = nonLoggedInViewController
default:
guard self.activeViewController! is GothereMainMenuViewController else { return }
let alreadyLoggedInViewController = storyboard.instantiateViewController(withIdentifier: Constants.StoryboardIDs.StudentEventDashboardStoryboardID) as! StudentSegmentedTableViewController
self.navigationController.setViewControllers([alreadyLoggedInViewController], animated: false)
self.navigationController.popToViewController(alreadyLoggedInViewController, animated: true)
self.activeViewController = alreadyLoggedInViewController
}
}
let nonLoggedInViewController = storyboard.instantiateViewController(withIdentifier: Constants.StoryboardIDs.GothereMainMenuStoryboardID) as! GothereMainMenuViewController
let alreadyLoggedInViewController = storyboard.instantiateViewController(withIdentifier: Constants.StoryboardIDs.StudentEventDashboardStoryboardID) as! StudentSegmentedTableViewController
activeViewController = nonLoggedInViewController
switch Auth.auth().currentUser != nil {
case true:
activeViewController = alreadyLoggedInViewController
default:
break
}
navigationController = UINavigationController.init(rootViewController: activeViewController)
self.window?.rootViewController = navigationController
self.window?.makeKeyAndVisible()
I tried just this alone at first, and it didn't work so then I implemented a state listener in reasonable spots in my app.
First I added one that enables right after successful log in/signup and the segue is performed .
func enableAuth() {
authListener = Auth.auth().addStateDidChangeListener { (_, user) in
print("State Listener activated")
}
}
This is what I call in the viewDidLoad() of the segued viewController right after login/signup. To remove it, I simply call it when the logout button is pressed..
func disableAuthState() {
Auth.auth().removeStateDidChangeListener(self.authListener!)
print("State Listener Deactivated")
}
func studentLogoutSelected() {
var text = UITextField()
let alert = UIAlertController(title: "Logout", message: "Are you sure you want to logout?", preferredStyle: .alert)
let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
self.dismiss(animated: true, completion: nil)
}
let logoutAction = UIAlertAction(title: "Logout", style: .default) { (logoutAction) in
let firebaseAuth = Auth.auth()
do {
try firebaseAuth.signOut()
self.disableAuthState()
self.performSegue(withIdentifier: Constants.Segues.studentLogout, sender: self)
} catch let signOutError as NSError {
print("There was an error signing the user out. \(signOutError)")
}
}
alert.addAction(cancelAction)
alert.addAction(logoutAction)
present(alert, animated: true, completion: nil)
}
After all these functions and implementations, the shown blocks of code still don't do what I expected them to do. If anybody can point out issues or suggestions, that would be great, thanks.
First of all are you add FirebaseApp.configure() on your didFinishLaunchingWithOptions function in appdelegate? Then, Can you try call enableAuth in viewWillAppear()
Basically I am currently adding functionX to everywhere i present an UIAlertController as seen below:
let alert = UIAlertController(title: "", message: "", preferredStyle: .alert)
let okAction = UIAlertAction(title: "ok", style: .default)
alert.addAction(okAction)
functionX(actionSheet: alert, controller: self)
self.present(alert, animated: true, completion: nil)
// or it can be
// tableviewController.present(alert, animated: true, completion: nil)
Instead of calling functionX every time, I want to override a present method and call functionX there. I attempted the following:
extension UIViewController {
override func present(_ viewControllerToPresent: UIViewController, animated flag: Bool, completion: (() -> Void)? = nil) {
if (viewControllerToPresent is UIAlertController) {
functionX(actionSheet: viewControllerToPresent, controller: /* what should this be? */ )
}
super.present() //error here
}
}
Is this an appropriate approach? Can you help me fill the missing parameters?
i.e.:
What should be the controller? What would self or tableviewController from the first code stub be in the overriding present function?
How should I call the present method in the overriding present function?
According to the Swift guide,
Extensions can add new functionality to a type, but they cannot override existing functionality.
So you shouldn't really be overriding an existing method in a UIViewController in an extension.
What you could do is, to add your own present, called functionXAndPresent:
extension UIViewController {
func functionXAndPresent(_ viewControllerToPresent: UIViewController, animated flag: Bool, completion: (() -> Void)? = nil) {
if (viewControllerToPresent is UIAlertController) {
// to answer your second question, you should use "self" here
functionX(actionSheet: viewControllerToPresent, controller: self)
}
present(viewControllerToPresent, animated: flag, completion: completion)
}
}
You can't do this by overriding because as you have found out, you can't really refer to the "non-overridden" method at the end. super.present doesn't work because you are in an extension, not a subclass.
You can simply create a common method showAlert(with:and:) in a UIViewController extension and call functionX when the alert is presented, i.e.
extension UIViewController {
func showAlert(with title: String?, message: String?) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
let okAction = UIAlertAction(title: "OK", style: .default)
alert.addAction(okAction)
self.present(alert, animated: true, completion: {
self.functionX(actionSheet: alert, controller: self)
})
}
func functionX(actionSheet: UIAlertController, controller: UIViewController) {
//your code here...
}
}
Usage:
Call the showAlert(with:and:) method from whatever controller you want to, be it a UIViewController or a UITableViewController or any other, i.e
self.showAlert(with: "Alery..!!!", message: "This is a sample alert.")
Overrides of NSObject's derivatives in Swift's static extensions is only for Objective-C compatibility. You cannot override in extensions of pure Swift declarations. Think of it in such manner that if the class itself adds an override, and then a static extension adds an override. Which implementation should the linker link? And which implementation does super call refer to? In Objective-C this behavior is undefined, in Swift the extension override is ignored all together.
What you could do instead is move the overriding function from the extension directly to the class.
I have a tableview definition in which I am attempting to invoke an UIAlertController popup. I installed a button in the prototype tableView cell, when the button is touched, an IBAction handles the event. The problem is that the compiler won't let me.
present(alertController, animated: true, completion: nil)
Generates compiler error: "Use of unresolved identifier 'present'
Here is the code:
class allListsCell: UITableViewCell {
#IBOutlet var cellLable: UIView!
#IBOutlet var cellSelected: UILabel!
var colorIndex = Int()
#IBAction func cellMarkButton(_ sender: UIButton, forEvent event: UIEvent) {
if colors[self.colorIndex].selected == false {
colors[self.colorIndex].selected = true
cellSelected.text = "•"
let alertController = UIAlertController(title: "???", message: "alertA", preferredStyle: .alert)
let OKAction = UIAlertAction(title: "dismiss", style: .default) { (action:UIAlertAction!) in
print("Sand: you have pressed the Dismiss button");
}
alertController.addAction(OKAction)
present(alertController, animated: true, completion: nil) // ERROR
} else {
colors[self.colorIndex].selected = false
cellSelected.text = ""
}
}
If I comment that one line, the app runs correctly for each cell...
You can't call present AlertController inside a tableView cell , it needs a subclass of UIViewController or other equivalent one , you should use a delegate or some sort of notification to handle that , see my answer here for the same problem AlertControllerCallInsideCell
Edit : Form Docs , it's an instance method inside UIViewController . so it can't be called inside any other class of other type (UITableViewCell) in your case
It is not possible to call the "present" method from a TableViewCell, I recommend having a function in the main controller to show your UIAlertController.
Using this code you can instantiate the parent driver and execute any available function:
extension UIView {
var parentViewController: UIViewController? {
var parentResponder: UIResponder? = self
while parentResponder != nil {
parentResponder = parentResponder!.next
if let viewController = parentResponder as? UIViewController {
return viewController
}
}
return nil
}
}
//UITableViewCell
if let controller = self.parentViewController as? YourController
{
controller.showAlert()
}
Here is an example of its use with a CollectionViewCell:
https://github.com/AngelH2/CollectionViewCell-Comunication/tree/master/CollectionCellAction
I have a UIViewController which loads up some json data from the server. If the server is down or the user has data turned off I throw up an alert telling the user such. This is done using a UIAlertController. This works great. So I put this into an extension since it is used by all UIViewControllers which need data. Now the UIAlertController has an action set as well
Alert code
extension UIViewController {
func connectionLost(){
var message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: {
action in
//call function in the viewcontroller that raised this alert to reload the data
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
When the user taps the retry button I want to call a function in the uiviewcontroller that raised the alert.
I tried creating a delegate in the extension but struggled with getting it wired up like you do in a class. What sort of approaches are there to call a function from an extension in the viewcontroller that raised the alert?
You should create a BaseViewController and use Inheritance. It could be useful for other implementations too.
class BaseViewController: UIViewController {
func onRetryClick() {
// override to customize or write here the common behaviour
}
}
class FirstViewController: BaseViewController {
override func onRetryClick() {
// do something specific for FirstViewController
}
}
class SecondViewController: BaseViewController {
override func onRetryClick() {
// do something specific for SecondViewController
}
}
class ThirdViewController: BaseViewController {
// if you don't override this method, super class (BaseViewController) implementation will be executed
}
extension BaseViewController {
func connectionLost(){
var message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: { action in
self.onRetryClick()
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
Hope this makes sense.
class MyVC: UIViewController {
func retry() {
}
func checkConnection() {
connectionLost { (retry) -> (Void) in
if retry {
self.retry()
}
}
}
}
extension UIViewController {
func connectionLost(completion: #escaping (_ retry: Bool) -> (Void)) {
let message = "Your device has lost connection to the server. Check that you have a valid internet connection and then retry."
let alertController = UIAlertController( title: "Connection Lost",
message: message,
preferredStyle: .alert)
let retryAction = UIAlertAction(title:"Retry", style: .default, handler: {
action in
completion(true)//may be 'false', you decide
})
alertController.addAction(retryAction)
self.present(alertController, animated: true, completion: nil)
}
}
I have a setting where I used UIAlertController to show progress of a task till the task has some status to return.
The code looks like this
class AlertVCDemo: UIViewController {
let alertVC = UIAlertController(title: "Search",
message: "Searching....", preferredStyle:
UIAlertControllerStyle.Alert)
override func viewDidLoad() {
super.viewDidLoad()
alertVC.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { action in
switch action.style{
case .Default:
print("default")
case .Cancel:
print("cancel")
case .Destructive:
print("destructive")
}
}))
}
func showAlertVC() {
dispatch_async(dispatch_get_main_queue(), {
self.presentViewController(self.alertVC, animated: true, completion: nil)
})
}
#IBAction func searchButtonClicked(sender: AnyObject) {
showAlertVC()
// Now do the real search that will take a while,
// depending on the result change the message of the alert VC
}
}
Somehow I see that the alert view controller is not shown in the main thread. The search logic completes eventually. I am using iOS 9.3. I did thorough research before asking this question and none of the solutions suggested on similar threads helped. Not sure why dispatch_async doesn't present the alert VC when search is still happening.
Even if I have the dispatch_async not in a method, things don't change.
#IBAction func searchButtonClicked(sender: AnyObject) {
showAlertVC()
// Now do the real search that will take a while,
// depending on the result change the message of the alert VC
}
is called in the main thread. So i guess your "search code" is blocking the UI thread.
Try something like this
#IBAction func searchButtonClicked(sender: AnyObject) {
showAlertVC()
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)) {
// put your search code here
}
}
Check for UIViewController's presentedViewController property. It should be nil. If it is not nil, presentViewController method wont work.