I am swift beginner and I am struggling with my first application. Sorry if my question is too basic, but I get an error message in my code here:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
let secVC: NavigationViewController = segue.destinationViewController as! NavigationViewController // here is the error
secVC.receiveImeNaSladkarnica = Label1.text!
secVC.KordaA = Shirina.text!
secVC.KordaB = Duljina.text!
secVC.PodImeNaObekt = Label2.text!
I have created 2 different buttons: Navi Me and More Info buttons.
The first one (Navi Me) is connected with another view controller which is called NavigationViewContorller, there I send all of the data I need by using prepare for segue. Everything was working perfect, but now I have created another button which is called (MoreInfo).It is connected with 3rd viewcontroller called MoreInfoViewController. I think I have connected everything fine, but still when I click on the MoreInfo button the app stops working and I get the following error: Thread 1: signal SIGBART in the marked line. I cannot understand why is it breaking when this segue is for another view controller, nt for the MoreInfoViewController. Would you please advice me what to do or provide me with an example how to fix it
I have tried that:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
switch segue.identifier {
//error here-> case "VC1" :
let secVC: NavigationViewController = segue.destinationViewController as! NavigationViewController
secVC.receiveImeNaSladkarnica = Label1.text!
secVC.KordaA = Shirina.text!
secVC.KordaB = Duljina.text!
secVC.PodImeNaObekt = Label2.text!
//error here -> case "VC2" :
let secVC2: MoreInfoViewController = segue.destinationViewController as! MoreInfoViewController
secVC2.receiveImeNaSladkarnica = Label1.text!
secVC2.KordaA = Shirina.text!
secVC2.KordaB = Duljina.text!
secVC2.PodImeNaObekt = Label2.text!
default:
break
It still doesn't work
Each segue is supposed to have an unique string identifier.
For multiple view controllers use a switch statement
switch segue.identifier {
case "vc1" :
// prepare to go to vc1
case "vc2" :
// prepare to go to vc2
default : break
}
Once again my yesterday comment:
Since you are a beginner in Swift please learn first to consider the naming convention that variable names start with a lowercase letter.
Related
I've been looking through a Coordinator tutorial and it brought up a problem with code I've written in the past.
Namely, when reusing a view controller I've used a property to be able to display different elements depending on which view controller the user arrived from. This is described in the above tutorial as a hack.
For example I segue to labelviewcontroller using
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "label" {
let vc = segue.destination as! LabelViewController
vc.originalVC = self
}
}
and then on labelViewController have a property
var originalVC: ViewController?
which I then change the items in viewDidLoad() through
override func viewDidLoad() {
super.viewDidLoad()
if originalVC != nil {
label.text = "came direct"
imageView.isHidden = true
}
else {
label.text = "button"
imageView.isHidden = false
}
}
I've a working example project here: https://github.com/stevencurtis/ReusibilityIssues
Now, I know the answer might be use the Coordinator tutorial, but is there any other method that I can use to simple reuse a viewController for two different circumstances, rather than using a property or is there anyway to clean this up to be acceptable practice?
You can do that without passing originalVC just by checking parent type if you are pushing it inside a navigation controller like this :
if let p = parent {
if p.isKind(of: OriginalViewController.self){
//it pushed in navigation controller stack after OriginalViewController
}
}
but is there any other method that I can use to simple reuse a viewController for two different circumstances
If the "two different circumstances" you describe are very different (by this I mean "require very different lines of code to be run"), then you should create two different view controller classes, because otherwise you would be violating the Single Responsibility Principle.
If your "two different circumstances" are different, but also quite related, then you can just have all the information that the VC needs to know as properties. You certainly don't need a whole ViewController.
For example, if your LabelViewController will show a "foo" button only if it is presented by ViewControllerFoo.
You can add a showFooButton property in LabelViewController:
var showFooButton = false
override func viewDidLoad() {
fooButton.isHidden = !showFooButton
}
And then in ViewControllerFoo.prepareForSegue:
if segue.identifier == "label" {
let vc = segue.destination as! LabelViewController
vc.showFooButton = true
}
I wouldn't call this a hack. This is the recommenced way described in this post and they didn't call it a hack.
My app is split into 2 storyboards: a character selection one and a main application one. When the user selects a character the app segues's to the main application, and all the views of that storyboard should now relate to the character the user selected.
I'm trying to find out the best way to share a String that will have the selected character's information between all the main application storyboard's views. Right now I'm using UserDefaults to just set a global variable:
func loadMainApp(sender: UITapGestureRecognizer) {
let currentCharcter = allCharacters[(sender.view?.tag)!]
let defaults: UserDefaults = UserDefaults.standard
defaults.setValue(currentCharacter, forKey: "CurrentCharacter")
performSegue(withIdentifier: "MainAppSegue", sender: self)
}
From there all the view controllers in the Main App storyboard can fetch the string from UserDefaults.
Is this the best way of doing such a thing or is there a better way?
The better way is to pass the character to the viewController you are segueing to, and the easiest way to do that is with prepare(for segue. If you change your performSegue call to pass the sender on by saying performSegue(withIdentifier: "MainAppSegue", sender: sender) you will be able to access that in prepare(for like this:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
//Safely check to make sure this is the correct segue by unwrapping the sender and checking the segue identifier
if let tapGesture = sender as? UITapGestureRecognizer, let tapGestureView = sender.view, let mainViewController = segue.destination as? MainViewController, segue.identifier == "MainAppSegue" {
//Get a reference to the character that was selected
let currentCharacter = allCharacters[tapGestureView.tag]
//Pass the character to the new viewController
mainViewController.character = currentCharacter
}
}
I made a couple assumptions about the name of the viewController you are performing the segue to, and assumed it has a variable called character where you can send your character. Your new viewController now has a reference to the character.
If I understand you well. Personally I am using Singeltons for achieving Global variable between Views rather than UserDefaults
class SomeClass{
static let sharedInstance = SomeClass()
var someString = "This String is same from any class"
}
Usage inside of some function :
SomeClass.sharedInstance.someString = "Changing Global String"
I am creating an application in which there are 6 view controller in storyboard. The thing is that data is shared between the default view controller and the first one ( say A and B) which i added. i am using the prepareforseque method for passing data. the problem started when i added two more view controller. lets say C and D i created two new swift files and changed the two view controller class name. i created a textbox and button in C and label in D. when i pressed the button, the value of the text field is not passing into the D view controller although i used the same methods and code which i used for A and B. do i have to do anything else when i want to pass data between two newly added view controller.
first viewcontroller in which when a button is pressed value 1 needed to be passed:
class PlaySelectMenu: UIViewController {
var value = Int()
#IBAction func twotofive(sender: AnyObject) {
value = 1
}
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let nextView : PlayGameView = segue.destinationViewController as! PlayGameView
nextView.x = value
}
}
the second view controller which receive the value and print it
import Foundation
import UIKit
class PlayGameView: UIViewController{
var x = Int()
override func viewDidLoad() {
super.viewDidLoad()
print(x)
}
}
here i have added both the view controller from the object library and not working with the default one which is present in storyboard by default. i dont know why these two viewcontroller are not working. please help.
Regards Dev
One solution would be to write the data out to NSUserDefaults and then read it back from NSUserDefaults in the other view controller. Probably not the proper or correct way to share data between two view controllers, but it's been a reliable work around for me.
Other than that, you'd need to share your code so that we can see what's occurring.
Can you post also the code in your controllers C & D. And also if you have copy/paste the code inside your first two controllers into the two others, are you sure that in your prepareForSegue method you have changed the name of the destination segue ?
Assuming you have created the segue in Storyboard:
All you need is to do is put all of needed updates in prepareForSegue because twotofive is called after prepareForSegue.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
value = 1
let nextView : PlayGameView = segue.destinationViewController as! PlayGameView
nextView.x = value
}
Since you have connected your segue from button click to view controller, when you press button segue is automatically called. Instead of connecting segue from button to VC, connect VC to VC. Then in button click method at the last add below line:
#IBAction func twotofive(sender: AnyObject) {
value = 1
self.performSegueWithIdentifier("<Name of the segue identifier>", sender: self)
}
This will call your prepareForSegue. If you are calling more then one VC using segue from a VC then you can use segue.identifier to check which VC was called as below
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if segue.identifier == "CVC" {
}
I have several tableview. I am trying to make a simple application and after adding more view when I get the third tableView this error "Thread 1 Signal SIGABRT" and the app wont open in iOS Simulator. The error points to this line of code:
let VC :DetailCityTableViewController = segue.destinationViewController as! DetailCityTableViewController
and display error :
Could not cast value of type 'UITableViewController' (0x102af47f8) to 'balen.DetailCityTableViewController' (0x1013d7560).
(lldb)
Full Code :
tableview2 pass to tableView3
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let path : NSIndexPath = self.tableView.indexPathForSelectedRow!
if segue.identifier == "DetailCitySegue" {
let VC :DetailCityTableViewController = segue.destinationViewController as! DetailCityTableViewController
VC.urlDetailCity = urlDetail!// pass url city
VC.cityIdSelectet = cityId[path.row] //pas CountryID selected
print(cityId[path.row])
}
}
I am , I think the problem is segue .What do you think?
No, the problem is '
Could not cast value of type 'UITableViewController' (0x102af47f8) to
'balen.DetailCityTableViewController''
You didn't change the class type of the view controller to DetailCityTableViewController in interface builder or the segue has a different destination than you think.
Currently I have the application loading up the data in a tableview presented to the user that I want them to select the object they wish to view further details about. From their I want to be able to read out the data in the object to the user in various forms either labels or a tableview dependent on the data.
I have been reading around and trying to understand this stuff but it is all still new to me! I had another guy on here help me out with saving the data and passing the data around to store but reading it out is a seemingly different thing. Any examples in swift language would lead me down the right path I know that I need to use the didselectrow method and call a segue and also that I need a prepare for segue but I am not quite sure how it should look.
I have read multiple posts and some do actually attempt to pass objects but not in the manner in which I am trying to..Are you able to pass whole objects after they have been have been selected in a tableview to another view controller to present all data related to that object or are you only able to pass information from that object to the next viewcontroller? I have examples of prepareforsegue and perform segue before not sure what else I am missing but I am currently not able to pass any information between the tableview and the viewcontroller.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if (segue.identifier == "decktoRecord") {
var detailVC: StatWidgetViewController = segue.destinationViewController as! StatWidgetViewController
detailVC.deckRecord = decktoPass
}
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let indexPath = tableView.indexPathForSelectedRow()
let selectedCell = tableView.cellForRowAtIndexPath(indexPath!) as UITableViewCell?
self.performSegueWithIdentifier("decktoRecord", sender: indexPath);
}
decktoPass is just a variable that contains the type of data entity that is the primary entity of the object.
A little confused by what you're asking but from what I understand, once the user clicks on a cell you want to segue to another view controller where they can edit the the details?
To add an exception breakpoint, open up your left panel with all your files/viewcontrollers, at the very top of it should be a small panel with a few icons, the first one is a folder, click on the second last one (the one that looks like a tag)
click on the plus in the bottom right and click add exception breakpoint, this should let you know where the problem in your code is occurring
Okay to edit the details in another View controller start by preparing the segue from the original view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showTaskDetail" {
let detailVC: TaskDetailViewController = segue.destinationViewController as! TaskDetailViewController
let indexPath = self.tableView.indexPathForSelectedRow()
let thisTask = fetchedResultsController.objectAtIndexPath(indexPath!) as! TaskModel
detailVC.detailTaskModel = thisTask
detailVC.delegate = self
}
else if segue.identifier == "showTaskAdd" {
let addTaskVC:AddTaskViewController = segue.destinationViewController as! AddTaskViewController
addTaskVC.delegate = self
}
}
okay so like the code is showing above, I have a segue called showTaskDetail which shows the details of whatever it is, in my case its a simple task. You said you want to edit this information in another view controller when a user clicks on the row, well you need to be able to get this information in the other view controller.
So create a variable in the other viewcontroller that will hold these values, for me i called it detailTaskModel
var detailTaskModel: TaskModel!
Incase you're confused about what TaskModel is, I'm using CoreData to store my data, and TaskModel is a NSMangedObject class.
let detailVC: TaskDetailViewController = segue.destinationViewController as! TaskDetailViewController
this line you're just specifying what your other view controller is, replace TaskDetailViewController with your swift class.
let detailVC: TaskDetailViewController = segue.destinationViewController as! TaskDetailViewController
this line fetches the data from the row selected
Now you should be able to pass your information into the other view controller and edit it using the detailTaskModel, do you need help with that as well?