When using input structures to create multiple save arrays, do not display the array in a custom cell.
The following is the initialization settings
struct LearnList {
var Title:String
var Des:String
init (Title:String,Des:String){
self.Title = Title
self.Des = Des
}
}
The following is the method code after clicking Complete
#IBAction func Complete(_ sender: Any) {
if (InputTitleTextField.text != nil),
(InputDesTextField.text != nil)
{
let LearnString = LearnList(Title: InputTitleTextField.text!, Des: InputDesTextField.text!)
LearnArray.append(InfoString)
self.InputTitleTextField.text = ""
self.InputDesTextField.text = ""
}
}
Where should I insert the following code in the main ViewController?
（override） func viewDidAppear(_ animated: Bool) {
LearnTableView.reloadData()
}
What should be read in this area?
My learning reference link:
How To Create A To Do List App In Xcode 8 (Swift 3.0)
My question on programming in China，（there is still no answer）:
UITextField:用户输入append方法错误以及回答里的新问题无法传值的问题
The first question in detail the process of inquiry, later found their own programs to show the fixed characters, but the code was not saved, try to modify their own user input failed.
Add the reloadData() to the end of your Complete() not in the viewDidAppear()
Related
I keep getting a fatal error saying how a value was unwrapped and it was nil and I don't understand how. When I instantiate a view controller with specific variables they all show up, but when I perform a segue to the exact VC, the values don't show up.
Take these functions for example...
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
if let displayVC = storyboard?.instantiateViewController(withIdentifier: Constants.Storyboards.TeachStoryboardID) as? SchoolEventDetailsViewController {
displayVC.selectedEventName = events[indexPath.row].eventName
displayVC.selectedEventDate = documentsDate[indexPath.row].eventDate
displayVC.selectedEventCost = documentsCost[indexPath.row].eventCost
displayVC.selectedEventGrade = documentsGrade[indexPath.row].eventGrade
displayVC.selectedEventDocID = documentsID[indexPath.row]?.docID
navigationController?.pushViewController(displayVC, animated: true)
}
}
This combined with this function :
func verifyInstantiation() {
if let dateToLoad = selectedEventDate {
dateEditableTextF.text = dateToLoad
}
if let costToLoad = selectedEventCost {
costEditableTextF.text = costToLoad
}
if let gradesToLoad = selectedEventGrade {
gradesEditableTextF.text = gradesToLoad
}
if let docIDtoLoad = selectedEventDocID {
docIDUneditableTextF.text = docIDtoLoad
}
if let eventNameToLoad = selectedEventName {
eventNameEditableTextF.text = eventNameToLoad
}
}
Helps load the data perfectly, but when I try to perform a segue from a search controller the data is not there.
override func viewDidLoad() {
super.viewDidLoad()
navigationItem.title = selectedEventName
I set the title of the vc to have the event name , and I also recently added a text field to store it as well for experimental purposes (this question).
Now the issue is I want to do a data transfer from an Algolia Search Controller to that VC and I got all the other fields to show up, except for one and that was the document ID. So I created a completion handler function to get the document ID as a string and have it inserted into the vc when the segue is performed, just like how it's there when the vc is instantiated.
Here is the function :
func getTheEventDocID(completion: #escaping ((String?) -> ())) {
documentListener = db.collection(Constants.Firebase.schoolCollectionName).whereField("event_name", isEqualTo: selectedEventName ?? navigationItem.title).addSnapshotListener(includeMetadataChanges: true) { (querySnapshot, error) in
if let error = error {
print("There was an error fetching the documents: \(error)")
} else {
self.documentsID = querySnapshot!.documents.map { document in
return EventDocID(docID: (document.documentID) as! String)
}
let fixedID = "\(self.documentsID)"
let substrings = fixedID.dropFirst(22).dropLast(3)
let realString = String(substrings)
completion(realString)
}
}
}
I thought either selectedEventName or navigationItem.title would get the job done and provide the value when I used the function in the data transfer function which I will show now :
//MARK: - Data Transfer From Algolia Search to School Event Details
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
otherVC.getTheEventDocID { (eventdocid) in
if let id = eventdocid {
if segue.identifier == Constants.Segues.fromSearchToSchoolEventDetails {
let vc = segue.destination as! SchoolEventDetailsViewController
vc.selectedEventName = self.nameTheEvent
vc.selectedEventDate = self.dateTheEvent
vc.selectedEventCost = self.costTheEvent
vc.selectedEventGrade = self.gradeTheEvent
vc.selectedEventDocID = id
}
}
}
}
But it ends up showing nothing when a search result is clicked which is pretty upsetting, I can't understand why they're both empty values when I declared them in the SchoolEventDetailsVC. I tried to force unwrap selectedEventName and it crashes saying there's a nil value and I can't figure out why. There's actually a lot more to the question but I just tried to keep it short so people will actually attempt to read it and help since nobody ever reads the questions I post, so yeah thanks in advance.
I'm a litte confused what the otherVC is, which sets a property of itself in the getTheEventDocID, whilste in the closure you set the properties of self, which is a different controller. But never mind, I hope you know what you are doing.
Since getTheEventDocID runs asynchronously, the view will be loaded and displayed before the data is available. Therefore, viewDidLoad does not see the actual data, but something that soon will be outdated.
So, you need to inform the details view controller that new data is available, and refresh it's user interface. Something like
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
otherVC.getTheEventDocID { (eventdocid) in
if let id = eventdocid {
if segue.identifier == Constants.Segues.fromSearchToSchoolEventDetails {
let vc = segue.destination as! SchoolEventDetailsViewController
vc.selectedEventName = self.nameTheEvent
vc.selectedEventDate = self.dateTheEvent
vc.selectedEventCost = self.costTheEvent
vc.selectedEventGrade = self.gradeTheEvent
vc.selectedEventDocID = id
vc.updateUI()
}
}
}
}
and in the destination view controller:
class SchoolEventDetailsViewController ... {
override func viewDidLoad() {
super.viewDidLoad()
updateUI()
}
func updateUI () {
navigationItem.title = selectedEventName
// and so on
}
}
Ok so I decided to attempt a workaround and completely ditched the getTheEventDocID() method because it was just causing me stress. So I decided to ditch Firebase generated document IDS and just use 10 digit generated ids from a function I made. I also figured out how to add that exact same 10 digit id in the Algolia record by just storing the random 10 digit id in a variable and using it in both places. So now instead of using a query call to grab a Firebase generated document ID and have my app crash everytime I click a search result, I basically edited the Struct of the Algolia record and just added an eventDocID property that can be used with hits.hitSource(at: indexPath.row).eventDocID.
And now the same way I added the other fields to the vc by segue data transfer, I can now do the same thing with my document ID because everything is matching :).
I've successfully set my first view controller to STPAddCardViewController. I now need to get the user information in the STPPaymentCardTextField. Problem is, I'm used to using the storyboard to make outlets. How do I detect the STPPaymentCardTextField programmatically?
I've tried:
class ViewController: STPAddCardViewController, STPPaymentCardTextFieldDelegate {
let paymentCardTextField = STPPaymentCardTextField()
func paymentCardTextFieldDidChange(_ textField: STPPaymentCardTextField) {
print(paymentCardTextField.cardNumber)
//ERROR: printing nil in the console
}
}
But I'm getting nil as an output. Any help?
You should use either STPAddCardViewController, or STPPaymentCardTextField, not both. The SDK's ViewControllers are not designed to be extended. The intended use is:
class MyVC : STPAddCardViewControllerDelegate {
override func viewDidLoad() {
…
let addCardView = STPAddCardViewController()
addCardView.delegate = self
// Start the addCardView
self.navigationController.pushViewController(addCardView, animated: true)
}
…
func addCardViewController(_ addCardViewController: STPAddCardViewController, didCreatePaymentMethod paymentMethod: STPPaymentMethod, completion: #escaping STPErrorBlock) {
// TODO: do something with paymentMethod
// Always call completion() to dismiss the view
completion()
}
func addCardViewControllerDidCancel(_ addCardViewController: STPAddCardViewController) {
// TODO: handle cancel
}
}
But rather than my partial example I'd recommend reading these docs and trying out this example iOS code. Best wishes!
I am new to Swift and I am having issues with deleting a character from a UI Label that I have created. I am trying to make a simple phone dailer app, and I am trying ti implement a backspace button. My UI Label is called DailerLabel, and I know I'm supposed to use the dropLast() function but I keep running into issues about mismatching types or unwrappers. I am not really sure what I am supposed to do here. I tried the thing in the commented code which didn't work, and then I tried what I listed below which doesn't either. Could anyone help me?
#IBAction func backspaceButtonPressed(_ sender: UIButton) {
if (!((DailerLabel.text?.isEmpty)!)) {
// DailerLabel.text?.substring(to: (DailerLabel.text?.index(before: (DailerLabel.text?.endIndex)!))!)
let temp = DailerLabel.text
temp?.dropLast()
DailerLabel.text = temp
}
You can try this one, replace label with your own UILabel
var name: String = label.text! //shauket , for example
name.remove(at: name.index(before: name.endIndex))
print(name) //shauke
label.text = name
print(label.text!)
You are very close. dropLast actually returns the string without the last character and you haven't stored that to anything so there is no change. You also have to conver back to String from Substring.
#IBAction func backspaceButtonPressed(_ sender: UIButton) {
if (!((DailerLabel.text?.isEmpty)!)) {
let temp = DailerLabel.text ?? ""
DailerLabel.text = String(temp.dropLast())
}
}
Here's a better version
#IBAction func backspaceButtonPressed(_ sender: UIButton) {
guard
let text = dialerLabel.text,
!text.isEmpty
else {
return
}
dialerLabel.text = String(text.dropLast())
}
I am working on an iOS application that is built around a Tab View Controller. I have created a "Contacts" tab, where a user can find and select a contact from a list. When the user selects the contact, it takes the contact's name and passes it to a different tab. That function is being done like so:
func passName(name: String) {
let navTab = self.tabBarController!.viewControllers![2] as! UINavigationController
let homeTab = navTab.viewControllers[0] as! MainController
homeTab.passedName = name
tabBarController?.selectedIndex = 2
}
Everything works as it should so far (name is loaded into text field). My issue is that the value seems to keep coming back every time I change tabs and then go back to my Home tab. For example, if I select "John" from my contacts, it will take me to the Home Tab and put John's name in a textfield. Let's say I delete the last two letters of the name, so now it is "Jo". If I load a different tab and come back, the name field has been reset to "John". It's as if the value gets re-passed every time I open the Home Tab. Also, every time I load the Home Tab after passing a name, my console prints: "Name Passed: John", so it shows that this is being processed every single time the tab appears. Here is my code for processing the name:
var passedName: String!
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
//Checks if name was passed to controller
if let validName = passedName {
print("Name passed: \(validName)")
nameTextField.text = validName
}
}
Am I passing the data incorrectly? I was thinking it might be because I have the above code being called in the viewWillAppear method, but that doesn't make sense, as essentially the data is only being passed one time from the Contacts tab. Thanks!
The problem is that you're not actually passing the value back to the original view. Apple's recommendation for passing information between classes is to use the delegate pattern. This allows the modal view to call the delegate class's function, which changes the name local to the original view because that function is declared in the original view's viewController. You can read more about the pattern in this tutorial, but I've also included a brief example relevant to your use case below.
mainViewController:
class namesTableViewController: UITableViewController, editNameDetailsViewControllerDelegate {
var name : String
#IBAction func editButtonPressed(_ sender: UIBarButtonItem) {
performSegue(withIdentifier: "editPerson", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "editPerson" { //Modal segue
let navController = segue.destination as! UINavigationController
let controller = navController.topViewController as! editNameViewController
controller.delegate = self
if let person = sender as? Person {
print("Sending person to edit")
controller.personToEdit = person
}
} else {
super.prepare(for: segue, sender: sender)
}
}
//Protocol function
func changeName(n: String, controller: UIViewController) {
name = n
dismiss(animated: true, completion: nil)
}
}
editNameViewController:
class editNameViewController: UIViewController {
#IBOutlet weak var personNameTextField: UITextField!
var personToEdit : Person?
weak var delegate : PersonTableViewController?
override func viewDidLoad() {
super.viewDidLoad()
if personToEdit != nil {
personNameTextField.text = personToEdit?.name
}
}
// Button Actions
#IBAction func saveButtonPressed(_ sender: UIBarButtonItem) {
delegate?.personDetailsView(n: personNameTextField.text, controller: self)
}
}
Finally, the protocol class :
protocol editNameDetailsViewControllerDelegate : class {
func personDetailsView(n: String, controller: UIViewController)
}
Hope this helps.
The problem is "passedName" variable doesn't changed its value every time you edit it in your UITextField. Keep in mind that every time you change tabs, the UIViewController will call viewWillAppear and viewDidAppear. So your UITextField will always show passedName value once you select other tab and return.
I suggest that every time you edit the textfield you should update passedName value.
Sorry for my bad english.
I have an app with UITableView, Core Data and NSFetchedResultsController as well. I have passed data to the DetailViewController. And I can delete them from the DetailViewController! In the Apple's iOS Notes app, you can see such as functions as I wanted! When you delete a notes from the DetailViewController ( for example ), object deleted and Notes app automaticlly shows the next or previos notes! I want to create such as function. How update user interface after deleted current object? Here's my codes! Thanks `
import UIKit
import CoreData
class DetailViewController: UIViewController {
#IBOutlet weak var containerLabel: UILabel!
var retrieveData:NSManagedObject!
var managedObjectContext:NSManagedObjectContext!
var manager:Manager!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.containerLabel.userInteractionEnabled = false
self.containerLabel.textColor = UIColor.redColor()
self.containerLabel.alpha = 0
UIView.animateWithDuration(2.5) { () -> Void in
self.containerLabel.alpha = 1
}
if let demo = self.retrieveData.valueForKey("titleField") as? String {
self.containerLabel.text = demo
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func backToMain(sender: AnyObject) {
// Back to the MainTableViewController
self.dismissViewControllerAnimated(true, completion: nil)
}
#IBAction func trashButton(sender: AnyObject) {
self.managedObjectContext.deleteObject(retrieveData)
do {
try self.managedObjectContext.save()
} catch {
}
self.dismissViewControllerAnimated(true, completion: nil)
}
`
If I have 5 items on the list like so:
When I select fourth item from the list ( for example ). And detailVC shows me selected item like this:
And I want to delete them. When I delete "Four" and then my containerLabel.text shows previous objects from the list. They're after "Four" is deleted, "Three","Two" and "One" as well. After "One" is deleted my containerLabel.text shows strings
But I have left single object called as "Five"
My problem is "Five"! I can't delete it. Example: In iOS Notes App, if you have five objects on the list like my demo app. When you select fourth object from the list ( for example ). And begin deleting them, after "Four" is delete iOS Notes App shows "Five". And "Five" ( last object on the list ) is deleted and then iOS Notes App shows "Three", "Two" and "One". Maybe problem line is here:
if index != 0 {
self.retrieveData = fetchedObject[index! - 1]
} else {
self.retrieveData == fetchedObject[0]
}
Let's take the easy (but not so elegant) route here. You'll have to pass over all the fetched objects to the detail VC like this:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "yourSegueIdentifier"{
if let destinationVC = segue.destinationViewController as? DetailViewController{
destinationVC.managedObjectContext = yourContext
destinationVC.retrieveData = yourManagedObject
destinationVC.arrayOfFetchedObjects = yourFetchedResultsController.fetchedObjects
//pass over other data...
}
}
}
Then, in your detailVC, write a method that will be executed when you press the delete button. Something like this:
#IBAction func trashButton(sender: AnyObject) {
//make sure you have an array with YourObjects
guard let fetchedObjects = arrayOfFetchedObjects as? [YourObjectType] else {return}
//get index of the shown object in the array of fetched objects
let indexOfObject = fetchedObjects.indexOf(retrieveData)
//delete the object from the context
self.managedObjectContext.deleteObject(retrieveData)
do {
try self.managedObjectContext.save()
//delete the object from the fetchedObjects array
fetchedObjects.removeAtIndex(indexOfObject)
} catch {
}
//get the object that should be shown after the delete
if indexOfObject != 0{
//we want the object that represents the 'older' note
retrieveData = fetchedObjects[indexOfObject - 1]
updateUserInterface(true)
}
else{
//the index was 0, so the deleted object was the oldest. The object that is the oldest after the delete now takes index 0, so just use this index. Also check for an empty array.
if fetchedObjects.isEmpty{
updateUserInterface(false)
}
else{
retrieveData = fetchedObjects[0]
updateUserInterface(true)
}
}
}
func updateUserInterface(note: Bool){
switch note{
case true:
//update the user interface
if let demo = retrieveData.valueForKey("titleField") as? String {
self.containerLabel.text = demo
}
case false:
self.containerLabel.text = "no more notes"
}
}
You either need to pass the details view controller
A list of all managed objects and an index for where in the list to start
A current managed object and a callback to get the next object
In order for it to have enough information to do what you want. The callback approach is nicest and is a simple form of delegate, where your master view controller is the delegate supplying the extra data.