I have two views. The first one has a UITextView and a button. The second has a UILabel. When I click on the button I would like the text label of the second views to be filled with what was in the textfield of the first view.
I did the following:
#IBAction func tapButton() {
let vc = storyboard?.instantiateViewController(identifier: "second") as! SViewController
vc.l.text = t.text
vc.modalPresentationStyle = .fullScreen
present(vc, animated: true)
}
l is the UILabel and t is the UITextField. When I run this code it's telling me I am trying to unwrapped l whereas l is nil.
But why l is nil? I mean if I instantiate my second view then it should create the UILabel l and thus l is not nil?
This happens because your second view controller's view hierarchy hasn't loaded yet, that's why you're getting nil. Simple solution is to keep a string variable in the second view controller and set it in the button tap action. And then in viewDidLoad of the second view controller set the label text.
Related
My app has a TabBarController. Each tabBarItem relates to a ViewController embedded in a NavigationController.
When in first tabBarItem and selecting another tabBarItem I want to do some stuff before moving to the selected ViewController. Therefore I created a class for my tabBarController and made it UITabBarControllerDelegate.
What I want to do is present an alert with two buttons; button A cancels the move to the selected viewController and button B lets the move happen.
My problem is that when button B is pressed, I want to popToRootViewController. I gave the navigationController a storyboardID and tried to instantiate it like shown below.
func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
if let alert = self.storyboard?.instantiateViewController(withIdentifier: "ActiveSessionWarningAlert") as? ActiveSessionWarningAlert {
alert.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
alert.modalTransitionStyle = UIModalTransitionStyle.flipHorizontal
let alertWasDismissed: (Bool) -> Void = { userWantsToMoveToSelectedViewController in
if userWantsToMoveToSelectedViewController {
if let navContr = self.storyboard?.instantiateViewController(withIdentifier: "firstNavContr") as? UINavigationController {
navContr.popToRootViewController(animated: true)
}
tabBarController.selectedViewController = viewController
}
}
alert.alertWasDismissed = alertWasDismissed
self.present(alert, animated: true, completion: nil)
}
return false
}
Everything works as expected, but the popToRootViewController doesn't seem to occur; when selecting the first tabBarItem again the same viewController that was 'active' when we left the item is still showing.
I checked so that the viewController I want to pop is actually in the navigation stack and that the navContr != nil.
What am I missing?
You don't say so, but I'm assuming that the alertWasDismissed closure you pass to your alert view controller gets invoked when the user dismisses the alert.
The problem with your closure is this bit:
if let navContr = self.storyboard?.instantiateViewController(withIdentifier: "firstNavContr") as? UINavigationController
Any time you call instantiateViewController(withIdentifier:), you are creating a brand new, never before seen instance of a view controller (a navigation controller in this case.) That navigation controller has nothing to do with the one that belongs to the current tab that you are trying to dismiss. It doesn't have anything in it's navigation stack other than the root view controller that is defined in the storyboard.
What you need to do is find the navigation controller of the current tab in your tab bar controller's tabBarController(_:shouldSelect:) method, and pass that navigation controller to your alertWasDismissed closure.
At the time the tabBarController(_:shouldSelect:) method is called, the tab bar controller's selectedViewController should contain the current view controller. Replace the line above with:
if let navContr = tabBarController.selectedViewController? as? UINavigationController {}
That should work.
I have two uiviewcontrollers for filter purpose, from the first controller using the button i could present the second view controller, from the second view controller i have a tableview and select their rows and passing those row values to the first view controller. It passes the values good, but i again click the same button of the first controller, like wise previous it opens the second controller but the rows i already selected seem unselected.
sample code: for clicking the First controller button for opening the view controller
#objc func empFilterButton(_ sender: Any){
let controller = EmployeeFilterViewController()
self.navigationController?.pushViewController(controller, animated: true)
}
sample code: for selecting the rows and pass those values to first view controller
#objc func applyFilter(_ sender: Any){
let empViewCtrl = EmployeeViewController()
empViewCtrl.deptIdString = deptIdString
empViewCtrl.dateIdString = dateIdString
empViewCtrl.shiftIdString = shiftIdString
empViewCtrl.locationIdString = locationIdString
self.navigationController?.pushViewController(empViewCtrl, animated: true)
}
I've got a ViewControllerOne. ViewControllerOne is connected via Ctrl-Drag (in storyboard) to a menu-button mBtn (which means I don't know how it is implemented programmatically).
Clicking on this mBtn, a ViewOne appears (present modal). This ViewOne is bound to ViewControllerOne. ViewOne has a button btnOne.
Clicking on btnOne I want ViewOne to be dismissed and ViewTwo to be shown. ViewTwo belongs to ViewControllerTwo and to WindowControllerTwo.
The WindowControllerTwo-ViewControllerTwo-binding is the standard case as created on a new project.
I have the following code in the IBAction for button btnOne in ViewControllerOne:
#IBAction func onbtnOnePressed(sender: AnyObject){
let m_WindowControllerTwo = NSStoryboard(name: NSStoryboard.Name(rawValue: "Main"), bundle: nil).instantiateController(withIdentifier: NSStoryboard.SceneIdentifier("WindowControllerTwo")) as! NSWindowController // I have no custom class for the window controller as I don't really know what I can use it for ...
let m_ViewTwo = WindowControllerTwo.contentViewController as! ViewControllerTwo // my custom class for ViewTwo
m_ViewTwo.attributeIWantToPassToThisView = self.x // an attribute I want to pass from view a to view b
m_WindowControllerTwo.contentViewController = m_ViewTwo // passing the attribute from a to b
m_WindowControllerTwo.showWindow(self) // this does not work
self.dismiss(nil) // see NOTE
}
This code actually does not work. On debugging it step by step, I'm seeing the window/view flickering but not appearing...
NOTE: I could connect the button btnOne with a ctrl-drag to ViewControllerTwo. This works. But then the current ViewOne does not get dismissed!
Question: What am I doing wrong here? In iOS swift this also works. I don't quite get the WindowController stuff, so I'll need your advice on this.
Instead of this: m_WindowControllerTwo.showWindow(self)
use:
let application = NSApplication.shared()
application.runModal(for: wordCountWindow) //this will present WindowControllerTwo modally.
then to close your present controller add this line: PresentWindowControllerName.close()
Sorry for the newbie question but i am really stuck.
I have a UIViewController and 4 tableviews in an app. When i click on a button on the UIViewcontroller it segues to a UITableviewController called "Beach". When the user clicks on a cell of the table, it segues back to the UIViewController and displays the selected cells title as the buttons title. The problem that i am having is when i click on a nother button to a tableview and then clicks on the cell, the previous buttons title sets back to the previous title.
i have a prepare for segue function in the tables view controllers and this returns the selected table title (named : Titleoftable) to the main VC which, the strings.
the way i am currently doing it is to make a NSUserDefault below but the problem still remains the same - The value changes top "" every time i click on another table V---
let path = tableView.indexPathForSelectedRow
let cell = tableView.cellForRowAtIndexPath(path!)
let persistenceStoreKey = "MyStringKey"
let stringToStore = "\((cell?.textLabel?.text!)!)"
// Store data
NSUserDefaults.standardUserDefaults().setObject(stringToStore, forKey: persistenceStoreKey)
NSUserDefaults.standardUserDefaults().synchronize()
// Get data
let myStringt = NSUserDefaults.standardUserDefaults().stringForKey(persistenceStoreKey)
destination.textOfBeach = (myStringt)!
destination.isBeachSelected = true
}
I have been stuck on this problem for ages now! PLEASE HELP!!
PS- I am using swift-2 and Xcode7
Make sure that you are not pushing a new ViewController after you click on the tableview's cell. It gives me the impression that it might be the case since you are seeing only the title of the last cell you pressed.. Make sure you actually pop the tableview's controller instead of pushing a new one.
If you want to keep using NSUserDefaults, you could just call
navigationController?.popViewController(animated: true)
in your cellSelection function, and read the defaults value in the viewWillAppear of the main ViewController.
override func viewWillAppear(_ animated: Bool) {
let userDefault = NSUserDefaults.standard()
if let beachSelection = userDefault.string(forKey: "BeachControllerSelection") {
textOfBeach = beachSelection
isBeachSelected = true
}
//same for the rest of the other table view's selections
}
I have a bit of an odd problem. Note that everything is done programmatically, so please no storyboard suggestions. Here's the setup:
I have a Master-Detail view layout, where the Detail view is a map. The Master-view's table is filled with cells that represent annotation points on the map. When you tap on a cell, it focuses on that annotation on the map and opens a custom annotation view using a popover. Likewise, when you tap the annotation itself, the same popover opens. So far, so good.
Now, inside the popover and inside each cell there is an a button which, when pressed, should open a new view that fills the whole screen. The view would have information specific to its corresponding annotation.
Here is how I am trying to do it:
Class that has the map (MyDetailViewController)
public func openNewViewController(){
self.presentViewController(NewViewController(), animated: true, completion: nil)
}
Function call for cell button and popover button
func btnPressed(sender: AnyObject){
var dvc = MyDetailViewController()
dvc.openNewViewController()
}
When either button gets tapped, I get the same error:
Warning: Attempt to present NewViewController on DetailViewController whose view is not in the window hierarchy!
So, what does it mean that DetailViewController is not in the window hierarchy..? It must be since I see it, no?
Any idea how to fix this issue? Thanks in advance!
Your function openNewViewController() is doing nothing!
See the code
self.presentViewController(openNewViewController()) , animated : true , completion: nil)
is pointing to itself.
Instead try this :
public func openNewViewController(){
var newController = UIViewController() // or any other view you wish to instantiate
self.presentViewController(newController, animated: true, completion: nil)
}