Perform a segue programmatically - swift

Hi I'm trying to perform a segue programmatically without the Storyboard. Currently I have this as my code:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "popOutNoteExpanded" {
let vc = segue.destination as! ExpandedCellViewController
let cell = sender as! AnnotatedPhotoCell
sourceCell = cell
vc.picture = cell.imageView.image
print("button pressed")
}
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "popOutNoteExpanded", sender: indexPath)
}
When I click on the collection view cell it's saying that:
has no segue with identifier 'popOutNoteExpanded'.
Not sure how to perform my custom animated transition.

To trigger a segue programmatically, you have to follow steps:
1. Set it up in Storyboard by dragging your desired segue between two view controllers and set its identifier (for example, in your case is "popOutNoteExpanded") in Attributes Inspector section.
2. Call it programmatically
performSegue(withIdentifier: "popOutNoteExpanded", sender: cell)
Please check if you set its identifier correctly or not.
Besides, in your above code, you put an incorrect sender.
In your prepare() method, you use the sender as a UITableViewCell, but you call performSegue() with sender as a IndexPath.
You need a cell by calling:
let cell = tableView.cellForRow(at: indexPath)
And then you can perform a segue:
performSegue(withIdentifier: "popOutNoteExpanded", sender: cell)

Segues are components of storyboard. If you don't have a storyboard, you can't perform segues. But you can use present view controller like this:
let vc = ViewController() //your view controller
self.present(vc, animated: true, completion: nil)

Additional to the correct answer, please be aware that if you are in a navigation stack (say, you are in a Settings page and want to segue to an MyAccountVC) you should use:
let vc = MyAccountVC()
self.navigationController?.pushViewController(vc, animated: true)
If the navigated VC appears with a transparent background during the transition, just set the backgoundColor of it to .white.

In my case I was presenting a TableViewController, without a segue defined, and found it was necessary to instantiate from the storyboard otherwise tableViewCells couldn't be dequeued in cellForRowAt.
let vc = (storyboard.instantiateViewController(withIdentifier: "YourTableViewController") as? YourTableViewController)!
self.navigationController!.pushViewController( vc, animated: true)

Related

How can I categorize my TODOs?

I have two ViewControllers in the first I created a tableView where I can insert just a text into a cell.
In the SecondViewController I also have a tableView with the same function, bu HOW can I make it that when I click a cell in the first tableView, I can get into a separate SecondTableView (Array).
So I'm this far, but I think the categorize function must be in the didSelectRowAt, when I click a Row.
FirstViewController:
todos: This is a String Array (I want this as the Category)
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "hhh"{
//let destination = segue.destination as? UINavigationController
let vc = segue.destination as? SecondViewController
}
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let vc = storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController
//label name
vc?.name = todos[indexPath.row]
self.present(vc!, animated: true, completion: nil)
tableView.deselectRow(at: indexPath, animated: true)
self.performSegue(withIdentifier: "hhh", sender: indexPath)
let indexpath = todos[indexPath.row]
print("indexpath:\(indexpath)")
print("row: \(indexPath.row)")
}
}
In the SecondViewController I have a SecondArray=[String]() these are actually the Todos.
On both ViewControllers I can insert a cell with text but don't know how to pass the data back:=?
In the comments I suggested using a UISplitViewController, as this works well with any kind of master/detail type of app. (In fact, it's an Xcode project type.)
But in case you require using a UINavigationController, here's what I to to "toggle" between two views this way:
FirstViewController:
#IBAction func showFrameVC() {
updateMaskImage()
self.performSegue(withIdentifier: "ShowSecondView", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "ShowSecondView" {
if let vc = segue.destination as? FrameViewController {
vc.someValue = someValue
vc.firstVC = self
}
}
}
Basically, pass the instance of the first view controller along with any data you need to pass.
SecondViewController:
var someValue:String!
weak var subjectVC:FirstViewController!
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if isMovingFromParentViewController {
firstVC.someValue = someValue
}
}
Here you let the navigation controller do it's thing, which is pop the second view controller off the stack after passing back the data it changed. Since you are maintaining a weak value of the first view controller, you free up that memory when the second controller is released.
In your code, you are presenting your SecondViewController in 2 ways in same function.
self.present(vc!, animated: true, completion: nil)
and
self.performSegue(withIdentifier: "hhh", sender: indexPath)
intention of both lines are same, But 2 way of implementation.
if my thinking is right you don't have to perform segue (second line of code mentioned above and also No prepare for segue method).

UIViewController's prepare for segue method is not being called

I am trying to pass data from a tableview cell into a tab view controller to be used by the tab view controller's corresponding views. However the overriden func prepare method below is not being called and the program goes to the tab view controller bypassing this method totally.
Storyboard showing the views
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let selectedCarIndex = self.savedCarsTableVC.indexPathForSelectedRow?.row
let destVC = segue.destination as! TabBarController
destVC.selectedCar = savedCars[selectedCarIndex!]
}
I am expecting the selectedCar object to return data from the array however it's nil.
I would try setting the selectedCarIndex in tableView didSelectRow method. Also, make sure you want to be navigating to TabBarController and not some ViewController embedded in the TabBar.
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: IndexPath) {
self.performSegue(withIdentifier: "youridentifier", sender: indexPath)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let selectedCarIndex = sender as! IndexPath
let destVC = segue.destination as! TabBarController //Are you sure this is the correct ViewController to be casting to?
destVC.selectedCar = savedCars[selectedCarIndex.row]
}

Why is my data not passing to my second view controller from a table view?

I'm trying to pass the value to a second view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "headToDetail" {
let indexPath = self.tableView.indexPathForSelectedRow!.row
print("SELECTED INDEX \(indexPath)")
let destVC = segue.destinationViewController as! SecondViewController
print("Segue TEst \(self.toPass)")
destVC.vieSegue = self.toPass
}
I've remove the didSelectRowAtIndexPath and just going to use the Segue but when I tap on a row cell I get:
fatal error: unexpectedly found nil while unwrapping an Optional value
This is a major update to the original code.
the problem is, that you are creating a new ViewController at line
var destination = SecondViewController()
but then the controller simply deallocates because nothing is pointing to it (there is no reference to it and it falls out of scope). You haven't pushed into it, nor you performed any segue.
How to fix it? Basically there are two options.
Storyboard
If you're working with storyboards, you have to create a segue between the first ViewController and SecondViewController. You have to give it an identifier.
Then in didSelectRowAtIndexPath you will write
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
tableView.deselectRowAtIndexPath(indexPath, animated: true)
let row = indexPath.row
print(fruits[row])
self.toPass = fruits[row]
performSegueWithIdentifier("YOUR_SEGUE_IDENTIFIER", sender: nil)
}
then in prepareForSegue you'll set the property to the destination SecondViewController.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "YOUR_SEGUE_IDENTIFIER" {
let destVC = segue.destinationViewController as! SecondViewController
destVC.vieSegue = self.toPass!
}
}
Manual Push
The second option is to push the controller manually within the didSelectRowAtIndexPath method
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
tableView.deselectRowAtIndexPath(indexPath, animated: true)
let row = indexPath.row
print(fruits[row])
let destination = SecondViewController()
destination.vieSegue = fruits[row]
// if you are using navigation controller
navigationController?.pushViewController(destination, animated: true)
// if you want to present it modally
// presentViewController(destination, animated: true, completion: nil)
}
The second version doesn't force you to create segues.
It's empty because you create a new object...
var destination = SecondViewController()
...pass it your data...
destination.vieSegue = self.toPass!
...and then let it go out of scope without showing it, saving it, or doing anything else useful.

How to Push ViewController in UITableViewCell's #IBAction func

I have a UITableViewController and UITableViewCell and Cell's XIB Files.
My question is how to push UIViewController from cell?
in UITableViewCell.
#IBAction func pushBtnTapped(sender: AnyObject) {
// navigate to post view controller
let guest = self.storyboard?.instantiateViewControllerWithIdentifier("GuestCollectionVC") as! GuestCollectionVC
self.navigationController?.pushViewController(guest, animated: true)
}
I got an error message. self.storyboard is not UITableCell's member.
I know there is another way to implement this. But I have to implement in TableViewCell.
Ideally you'd push from the table view controller, in the didSelectRowAtIndexPath method call. Why do you say you have to implement it in the cell? There are other ways you could do that but from what you're saying this might be the best shot...
self.performSegueWithIdentifier("YourSegueId", sender: nil)
Then in prepareForSegue
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
//get the index path of the selected row
let indexPath = self.tableView.indexPathForSelectedRow
//just an example if you want to pass something to the other vc
let item = self.responseItems[indexPath!.row]
if segue.identifier == "YourSegueId" {
YourVC = segue.destinationViewController as! YourVC
YourVC.item = item
}
}
If you want to do it from the button you could do something like this in the prepareForSegue method... now you have the button and its index path
let button = sender as! UIButton
let view = button.superview
let cell = view?.superview as! YourCell
let indexPath = tableView.indexPathForCell(cell)

Master-Detail: UINavigatorController vs Storyboard Segue

Scenario: Master(TableView) --> Detail.
Modus Operandi: Select Row --> display DetailVC
As you can see below, I have a MasterVC embedded in a UINavigationController:
I currently display the DetailVC via pushing it into the UINavigationController's VC stack:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
println("tableView didSelectRowAtIndexPath")
let storyboard = UIStoryboard(name: "Bliss", bundle: nil);
let controller = storyboard.instantiateViewControllerWithIdentifier("DiaryPlayerVC") as DiaryPlayerViewController
self.navigationController?.pushViewController(controller, animated: true)
}
This works fine.
However, the 'prepareForSeque' doesn't fire:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showDiaryPlayer" {
if let indexPath = self.tableView.indexPathForSelectedRow() {
let object = objects[indexPath.row] as NSDate
// (segue.destinationViewController as DiaryPlayerViewController).detailItem = object
}
}
}
I understand that I probably have two (2) conflicting paradigms here:
1) Using the UINavigationController vs
2) Using the Storyboard Relationship.
So...
Option 1: it appears that I can remove the Segue link to have a storyboard stand-alone DetailVC.
Option 2: via Segue, I'm assuming I can remove the UINavigatorController from the link.
I'm currently using Option #1, launching the DetailVC via the UINavigationController.
Question: If I choose Option #2, how do I access (launch) the DetailVC ("Diary Player") from the Master's Row and hence, fire the Segue's 'prepareForSegue()'?
Answer: create a segue from the table view cell to the detail view controller.
Your screenshot shows that you already created a segue in your storyboard. Give that segue an identifier in its property inspectory. Then you can simply perform the segue in the didSelectRowAtIndexPath method:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
println("tableView didSelectRowAtIndexPath")
performSegueWithIdentifier("mySegueIdentifier", sender: nil)
}
Note: Ctrl-drag the segue from the TableViewController icon, not from the TableViewCell.