I have a root UIViewController that has its NSManagedObjectContext var set by AppDelegate (iOS8 app coded using Swift).
The root controller(the master view of a splitview controller) has a button whose action presents another UIViewController with the following code segment:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("addGeometricEntityContent") as! UIViewController
vc.managedObjectContext = self.managedObjectContext
self.presentViewController(vc, animated: true, completion: nil)
I get a compiler error as follows:
'UIViewController' does not have a member named 'managedObjectContext' for the line of code:
vc.managedObjectContext = self.managedObjectContextas a test
I tried adding a simple testPrint() function to the presented UIView Controller as a test and got a similar complaint that vc instance does have a method testPrint()
Is the vc instance created by storyboard.instantiateViewControllerWithIdentifier somehow different from a fully instantiated object?
If I remove the line
vc.managedObjectContext = self.managedObjectContext
the code works as expected and presents the UIViewController instance.
The application delegate object is accessible from everywhere, so you could write in your view controller
let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedObjectContext = appDelegate.managedObjectContext
I was able to correct the problem by down casting the UIViewController type to my specific controller type as follows:
let vc = storyboard.instantiateViewControllerWithIdentifier("addGeometricEntityContent") as! AddGeometricEntityContentViewController
Related
In have a UITabBarController with several UIViewControllers. Inside one of the controllers, when a certain condition is met, I want to instantiate another UIViewController which is a child of the same UITabBarController.
I keep getting this error "Application tried to present modally an active controller", but I don't understand how is scheduleNavController already active. I looked up several answers on SO, but I still don't understand what is my mistake and how can I solve it?
The flow of the app is like this: WelcomeViewController,LoginViewController,UITabBarController and the children of the UITabBarController.
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let tabController = storyboard.instantiateViewController(withIdentifier: "CentralTabBarControllerID") as! UITabBarController
if let viewControllers = tabBarController?.viewControllers {
let scheduleNavController = viewControllers[1] as! UINavigationController
let scheduleVC = scheduleNavController.childViewControllers[0] as! Schedule
tabController.present(scheduleNavController, animated: true, completion: {
scheduleVC.segmentedControlIndexReceivedFromClaimDetail = self.segmentedControlIndex
})
}
Thanks to Andreas Oetjen suggestion to use the selectedIndex of the UITabBarController I have come up with another solution. However, I still don't know exactly how I should fix my code from the original question to make it work.
//select index of the UIViewController we want to switch to
// get the UINavigationController for the tab we want to switch to
// get UIViewController to which we want to pass data
self.tabBarController?.selectedIndex = 1
let scheduleNavController = tabBarController?.viewControllers?[1] as! UINavigationController
let scheduleVC = scheduleNavController.childViewControllers[0] as! Schedule
scheduleVC.segmentedControlIndexReceivedFromClaimDetail = self.segmentedControlIndex
//remove the the current UIViewController from which we switch to another controller above.
let claimDetailNav = tabBarController?.viewControllers?[0] as! UINavigationController
let claimDetailVC = claimDetailNav.childViewControllers[1] as! ClaimDetail
claimDetailVC.removeFromParentViewController()
I have some ViewControlls for settings, info etc.
Users can close the app settings ViewController open(I mean popover the ViewController).
When local notification is received I want the the app go to the root viewcontroller and dismiss any popovers.
EDIT
this answer is only good if the VC you are trying to go back to does not need any special initialization, since this method creates a new instance of it. keep that in mind.
Try this method, it will remove anything in your stack of View Controllers and make a specific View Controller presented on screen:
func dismissAllAndNavigate(){
let appDelegate = UIApplication.shared.delegate as! AppDelegate
let window = appDelegate.window
let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let rootController = mainStoryboard.instantiateViewController(withIdentifier: "some identifier") as! UIViewController
window?.rootViewController = rootController
}
Just make sure that the name of the storyboard is correct and the identifier of the view controller in that storyboard is defined.
I am really struggling with what should be a simple bit of code.
I have an ios app that has 4 tabs in the uitabcontroller, depending on the a setting in another tab I wanted to replace the controller the first tab goes to. I found that I couldnt simply replace this first tab (although i managed it somehow for a couple of builds then it stopped working after a clean).
So I went for the option of replacing the viewcontrollers that the tab controller references with the .setViewControllers method. I call this from my viewcontroller after the viewdidload method.
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc0 = storyboard.instantiateViewControllerWithIdentifier("collection")
let vc4 = storyboard.instantiateViewControllerWithIdentifier("profilenews1")
let vc1: UIViewController! = storyboard.instantiateViewControllerWithIdentifier("news") as UIViewController
let vc2: UIViewController! = storyboard.instantiateViewControllerWithIdentifier("create") as UIViewController
let vc3: UIViewController! = storyboard.instantiateViewControllerWithIdentifier("search") as UIViewController
let controllers = [vc0,vc4]
self.tabBarController?.setViewControllers(controllers, animated: true)
From the research I have done this should work, setViewControllers is documented and I have seen numerous objective c examples but I get EXEC_BAD_INSTRUCTION thrown.
I have checked that the tabcontroller is correct before I replace by doing
println("number of navs: \(self.tabBarController?.viewControllers?.count)")
And that prints the correct number of controllers.
Any ideas?
I am trying to add some unit tests to my project to test view controllers. However I seem to be having problems with seemingly simple things. I have created a sample project which I will refer to. https://github.com/pangers/ViewControllerTesting
The sample contains a UINavigationController as the initial view controller. The root view controller of the UINavigationController is FirstViewController. There is a button on FirstViewController that segues to SecondViewController. In SecondViewController there is an empty textfield.
The two tests I am trying to add are:
1) Check button title in FirstViewController is "Next Screen".
2) Check textfield in SecondViewController is empty, "".
I have heard reports of adding your swift files to both the main target and the test target is not good practice. But rather it is better to make whatever you want to access in your tests public and import the main target into the tests. So that is what I have done. (I have also set the "Defines Module" for the main target to YES as that is what I have read in a few articles aswell).
In FirstViewControllerTests I have instantiated the first view controller with the following:
var viewController: FirstViewController!
override func setUp() {
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle(forClass: self.dynamicType))
let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
viewController = navigationController.topViewController as FirstViewController
viewController.viewDidLoad()
}
And I have added the test:
func testCheckButtonHasTextNextScreen() {
XCTAssertEqual(viewController.button.currentTitle!, "Next Screen", "Button should say Next Screen")
}
Similarly, for SecondViewControllerTest, I have set it up using:
var secondViewController:SecondViewController!
override func setUp() {
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle(forClass: self.dynamicType))
let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
let firstviewController = navigationController.topViewController as FirstViewController
firstviewController.performSegueWithIdentifier("FirstToSecond", sender: nil)
secondViewController = navigationController.topViewController as SecondViewController
secondViewController.viewDidLoad()
}
And the test:
func testTextFieldIsBlank() {
XCTAssertEqual(secondViewController.textField.text, "", "Nothing in textfield")
}
They both fail and I am not too sure as to why. My suspicion is that the way I am instantiating the view controllers is not correct. Is the best way to instantiate the view controllers is to use the storyboard (just like it would if it were to run in real life)? Or is it acceptable to be instantiated via:
var viewController = FirstViewController()
What are you guys' experience with TDD and view controllers in swift?
I am using Swift with XCode 6.1.1.
Thanks in advance.
Solved
Ok after considering the answers from modocache and Mike Taverne, I've found my solution and I've learnt a few things which I will write down below.
1) I made anything class/method/variable that I want to test public. I do not need to add the swift files to the test target.
2) I only needed to set "Defines Module" for the "Main" target (as opposed to the "Test" target or the entire project)
3) When instantiating the storyboard, the bundle should be set to nil rather than NSBundle(forClass: self.dynamicType), otherwise tests will fail.
4) As modocache stated, it is good to give your view controller's a StoryboardID and instantiate them like so:
viewController = storyboard.instantiateViewControllerWithIdentifier("FirstViewController") as FirstViewController
However, instantiating the view controller like this ONLY instantiates the view controller alone, and not any navigation controllers that it may be embedded in. That means, attempting to do
XCTAssertFalse(viewController.navigationController!.navigationBarHidden, "Bar should show by default")
will result in a nil exception. I confirmed this with
XCTAssertNil(viewController.navigationController?, "navigation controller doesn't exist")
which resulted in a successful test.
Since I wanted to check the state of the navigation bar in FirstViewController, you must instantiate the view controller like so:
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let navigationController = storyboard.instantiateInitialViewController() as UINavigationController
viewController = navigationController.topViewController as FirstViewController
Now performing the test
XCTAssertFalse(viewController.navigationController!.navigationBarHidden, "nav bar should be showing by default")
results in a successful test.
5) let _ = viewController.view does indeed trigger viewDidLoad() which was confirmed by a test
6) let _ = viewController.view does not trigger viewWillAppear(), and I presume anything afterwards aswell. viewController.viewWillAppear(false/true) needs to be called manually to trigger it (Confirmed by a test).
Hopefully this will be of help to people. I will push the updated project to GitHub (link above) if anyone would like to play around with it.
Update #2
After all the above, I still could not figure out how to transition from the first view controller to the second view controller (so that I may test navigation bar properties in SecondViewControllerTests.swift). I tried
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
let firstVC = nc.topViewController as FirstViewController
firstVC.performSegueWithIdentifier("FirstToSecond", sender: nil)
secondVC = nc.topViewController as SecondViewController
which caused an error.
I also tried
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
let firstVC = nc.topViewController as FirstViewController
firstVC.toSecondVCButton.sendActionsForControlEvents(UIControlEvents.TouchUpInside)
secondVC = nc.topViewController as SecondViewController
which did not work.
I eventually tried
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let nc = storyboard.instantiateInitialViewController() as UINavigationController
vc = storyboard.instantiateViewControllerWithIdentifier("Second") as SecondViewController
nc.pushViewController(vc, animated: false)
let _ = vc.view
vc.viewWillAppear(false)
which worked perfectly with my tests (allowed me to access navigation bar properties)!
I agree with #MikeTaverne's answer: I prefer accessing -[UIViewController view] in order to trigger -[UIViewController viewDidLoad], rather than calling it directly. See if the test failures for FirstViewController go away once you use this instead:
viewController = navigationController.topViewController as FirstViewController
let _ = viewController.view
I'd also recommend giving both view controllers identifiers in your storyboard. This will allow you to instantiate them directly, without accessing them via UINavigationController:
var secondViewController: SecondViewController!
override func setUp() {
let storyboard = UIStoryboard(name: "Main", bundle: NSBundle(forClass: self.dynamicType))
secondViewController = storyboard.instantiateViewControllerWithIdentifier("SecondViewController")
as SecondViewController
let _ = secondViewController.view
}
Check out my talk on testing UIViewController at Brooklyn Swift for details: https://vimeo.com/115671189#t=37m50s (my presentation begins around the 37'50" mark).
I've begun unit testing view controllers recently, and it poses some unique challenges.
One challenge is getting the view to load. Looking at your set up for FirstViewController, you are trying to do this with viewController.viewDidLoad().
My suggestion is to replace that line with this:
let dummy = viewController.view
Accessing the .view property will force the view to load. This will trigger the .viewDidLoad in your ViewController, so don't call that method explicitly in your test.
This approach is considered hacky by some people, but it is simple and effective. (See Clean way to force view to load subviews early)
As an aside, I am finding the best way to test view controllers is to move as much code out of the view controllers as possible into other classes that are more easily tested.
If your view controller is defined in a storyboard, then you need to instantiate it that way for your outlets to be set up properly. Trying to initialize it like an ordinary class won't work.
I need to pass some parameters from the appDelegate to a viewController before loading it.
This is the code i'm trying to use (in the appDelegate.swift):
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let secondView = storyboard.instantiateViewControllerWithIdentifier("tab") as UITabBarController
secondView.variable = "xxxx"
self.window?.rootViewController = secondView;
but the compiler shows the following error:
UITabBarController does not have a member named 'variable'
Even thought, in the TabBarController class (TabBarController.swift) i have the following:
import UIKit
class TabBarController: UITabBarController {
var variable:String!
...etc
What's the error?
Please give a clear explanation as i'm a beginner in Swift.
Thank you very much!!
You have TabBarController, but you instantiate as UITabBarController.
Your second line should be
let secondView = storyboard.instantiateViewControllerWithIdentifier("tab") as TabBarController