I'm trying to add a feature in my app, to add multiple members to one action at one time. The members are listed in a tableView and the user can select multiple rows at one time with the .allowsMultipleSelection = true function. I got the following code but this doesn't work. I think my idea would work but not in the way I have it in the code :
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let destination = segue.destination as? AddMultipleMemberTransactionViewController,
let selectedRows = multipleMemberTableView.indexPathsForSelectedRows else {
return
}
destination.members = members[selectedRows]
}
Does somebody out here know, how I can solve this problem, because there is an error :
Cannot subscript a value of type '[Member?]' with an index of type '[IndexPath]'
I have the same feature in the app but just for one member. There I in the let selectedRows line after the indexPathForSelectedRow a .row. Is there a similar function for indexPathsForSelectedRows ?
Or is this the wrong way to do it?
You need
destination.members = selectedRows.map{ members[$0.row] }
As the indexPathsForSelectedRows indicates, it returns an array of IndexPath. What you need to do is create an array of Member objects based on those path.
Assuming you have a "members" array that contain all the members the user can select from, and your table has only 1 section:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
var selectedMembers: [Member] = []
guard let destination = segue.destination as? AddMultipleMemberTransactionViewController,
let selectedIndexes = multipleMemberTableView.indexPathsForSelectedRows else {
return
}
for selectedIndex in selectedIndexes {
let selectedMember = members[selectedIndex.row]
selectedMembers.append(selectedMember)
}
destination.members = selectedMembers
}
You can also use the array map() function to change the for loop into a single line operation:
let selectedMembers: [Member] = selectedRows.map{ members[$0.row] }
Both should effectively do the same.
Related
I am using a segue to go from View Controller 1 to View Controller 2. View Controller 1 has a button that sets the persistent data when it is clicked on:
I declare a global var for user default:
let userDefault = UserDefaults()
Here is my button to set the user default to a string with text values from labels:
#IBAction func saving(_ sender: UIButton) {
let savedText = "Gallon \(gallonTextFieldOutlet.text) is equal to Litre \(litreTextFieldOutlet.text) is equal to Pint \(pintTextFieldOutlet.text)"
userDefault.setValue(savedText, forKey: "SavedConversion")
}
I then get a reference to View Controller 2 and pass this user default when the user goes from View Controller 1 to View Controller 2 via a segue:
// in view controller 2: reference to get persistent data
var volumeDataOne:String?
// in view controller 2: instantiation of my queue class to use methods
var queue = Queue<String>()
// segue action in view controller 1
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "savedVolumeData"
{
let historyVC:VolumeHistoryViewController = segue.destination as! VolumeHistoryViewController
if let value = userDefault.value(forKey: "SavedConversion") as? String {
historyVC.volumeDataOne = value
}
}
I get this in the View Controller 2 and I am trying to set this to three labels that I have in this View Controller:
func DisplayVolumeHistory() {
let labelArray = [volumeDataLabelOutlet, volumeDataLabelTwoOutlet, volumeDataLabelThreeOutlet]
if let bindingOptional = volumeDataOne
{
for index in 0..<labelArray.count
{
queue.enqueue(val: bindingOptional)
labelArray[index]?.text = queue.arr[index]
}
}
}
In my specification, I have been told that the data needs to be persistent and that only the last five data can be stored at one time. So I have a class that I have called Queue which is referenced in this function. This function gets called on the viewDidLoad of the View Controller 2.
override func viewDidLoad() {
super.viewDidLoad()
//Debug ...
volumeDataLabelOutlet.text = "na"
volumeDataLabelTwoOutlet.text = "na 2"
volumeDataLabelThreeOutlet.text = "na 3"
//...
DisplayVolumeHistory()
// Do any additional setup after loading the view.
}
I have tested my Queue class in a Playground and it works as expected. The Queue class can be seen here:
class Queue {
var arr = [T]()
func enqueue(val: T){
if(arr.count < 3) {
arr.append(val)
} else {
for i in 0..<arr.count-1 {
arr[i] = arr[i + 1]
}
arr[arr.count - 1] = val
}
}
func dequeue() -> (T?){
if (arr.isEmpty){
return nil
} else {
return arr.remove(at: 0)
}
}
}
Here is my issue that I cannot seem to figure out. In View Controller 2, all of the three labels will have persistent data, but they will all be of the same data,
For example, if I have data as follows:
DATA 1: 555
DATA 2: 700
DATA 3: 62
I would want:
LABEL 1 --> 555
LABEL 2 --> 700
LABEL 3 --> 62
However, currently it will be:
LABEL 1 --> 62
LABEL 2 --> 62
LABEL 3 --> 62
I am unsure as to why debugging. I believe it is because my persistent data in my View Controller 1 is only taking a string, which the Dictionary is overriding as I use the same key.
However, I looked at the documentation and trying to use a user default array did not solve my issue and I am unsure as to what is causing this problem.
I appreciate any guidance and help to try to solve this issue.
Thanks
You are right on your comment,
which the Dictionary is overriding as I use the same key
Each time you tap that button, you are overriding the value with the new one. So you should be seeing always on your v2, the last one.
So probably you should store an array instead of a String.
//on v1
var values = [String]()
#IBAction func saving(_ sender: UIButton) {
let savedText = "Gallon \(gallonTextFieldOutlet.text) is equal to Litre \(litreTextFieldOutlet.text) is equal to Pint \(pintTextFieldOutlet.text)"
values.append(savedText)
UserDefaults.standard.setValue(values, forKey: "SavedConversion")
}
You will pass it to v2 as you are doing now
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "savedVolumeData"
{
let historyVC:VolumeHistoryViewController = segue.destination as! VolumeHistoryViewController
if let values = userDefault.value(forKey: "SavedConversion") as? [String] {
historyVC.volumeDataOne = values //volumeDataOne now needs to be an [String]
}
}
Then on V2, go through your array and labels.
I'm new to swift and firebase services,
I'm using fire store data base as my database and I have a first table view that reads all the data and put it in a nice tableview. every document in my table view has a sub collection. when a user press a row I want it to open a second table view with the sub collection.
this is my prepare for segue code :
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let indexPath = tableViewDishes.indexPathForSelectedRow {
db.collection("Restaurants").document("Applebees").collection("Menu").document(sections[indexPath.section].sectionName!).collection("Dishes").document(sections[indexPath.section].listofDishes![indexPath.row].DishName).collection("Options").getDocuments { (querySnapshot, error) in
if error != nil {print(error)}
else {
for document in querySnapshot!.documents {
//adding all the data to an array called myOption
}
}
}
let selectedDishTableViewController = segue.destination as! SelectedDishViewController
selectedDishTableViewController.myOption = self.myOption
selectedDishTableViewController.dish = self.sections[indexPath.section].listofDishes?[indexPath.row]
selectedDishTableViewController.sectionName = sections[indexPath.section].sectionName!
self.myOption.removeAll()
}
}
the issue is that once my code reach the db.collection line it jumps right away to after the for loop when myOption is a empty array and only then it comes back and appending objects to my array.
that cause the first time I press a row get an empty second table view and when I go back and press it again I get the required information.
db.collection() does some async work, so all this code:
let selectedDishTableViewController = segue.destination as! SelectedDishViewController
selectedDishTableViewController.myOption = self.myOption
selectedDishTableViewController.dish = self.sections[indexPath.section].listofDishes?[indexPath.row]
selectedDishTableViewController.sectionName = sections[indexPath.section].sectionName!
self.myOption.removeAll()
should be right before the for loop where you set myOption array. That way, everything will be set up once the database has retrieved all the data and you have made all the setup inside the for loop.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let indexPath = tableViewDishes.indexPathForSelectedRow {
db.collection("Restaurants").document("Applebees").collection("Menu").document(sections[indexPath.section].sectionName!).collection("Dishes").document(sections[indexPath.section].listofDishes![indexPath.row].DishName).collection("Options").getDocuments { (querySnapshot, error) in
if error != nil {print(error)}
else {
for document in querySnapshot!.documents {
//adding all the data to an array called myOption
}
let selectedDishTableViewController = segue.destination as! SelectedDishViewController
selectedDishTableViewController.myOption = self.myOption
selectedDishTableViewController.dish = self.sections[indexPath.section].listofDishes?[indexPath.row]
selectedDishTableViewController.sectionName = sections[indexPath.section].sectionName!
self.myOption.removeAll()
}
}
}
}
Since its an Async call you might have to write the selectedDishTableViewController segue in the callback.
Recommendation : Seque delegate method should be simple and should not be handling all these db operation try to optimise it.
I am trying to take facebook values, such as name and email, and transferring them to another view controller where they populate their corresponding text fields. However, when I try to populate the text fields with this code
let fbEmail = data["email"]
let fbName = data["name"]
func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let vc = segue.destination as? CreateAccountVC
vc!.emailTxt = self.fbName
vc!.fullnameTxt = self.fbEmail
}
I receive an error saying "Cannot assign type String to type UITextField!" I'm confused here as I thought that text fields only take strings (I'm very new to coding/programming).
So basically, how do I get these values gathered in one view controller to populate text fields in another view controller? Any help would be greatly appreciated! Thanks!
Error reason is you need to assign it to the UITextField's text property.
You can also use variables to set them. And set textfield's values in your CreateAccountVC controller's viewDidLoad function. Like this:
Your first controller where you take facebook values:
let fbEmail = data["email"]
let fbName = data["name"]
func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let vc = segue.destination as? CreateAccountVC {
vc.emailTxtValue = self.fbName
vc.fullnameTxtValue = self.fbEmail
}
}
Your CreateAccountVC :
class CreateAccountVC: UIViewController {
var emailTxtValue:String?
var fullnameTxtValue:String?
override func viewDidLoad() {
super.viewDidLoad()
emailTxt.text = emailTxtValue
fullnameTxt.text = fullnameTxtValue
}
}
I have a MapViewController with a prepareForSegue(_:sender:)method, which I intend to use to send data to LandmarkTableViewController, and is called when a button is pressed.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let destinationvc = segue.destinationViewController
if let landmarkvc = destinationvc as? LandmarkTableViewController {
if let identifier = segue.identifier {
let library = Landmark(name: "Run Run Shaw Library", properties: ["Chinese Kanji", "Gray", "Green Plants"])
let bank = Landmark(name: "Hang Seng Bank", properties: ["Chinese Kanji", "Green"])
switch identifier {
case "showLibrary" : landmarkvc.passedLandmark = library // pass data to LandmarkTableViewController
case "showBank" : landmarkvc.passedLandmark = bank // pass data to LandmarkTableViewController
default : break
}
}
}
}
The LandmarkTableViewController is properly set up to display the String array properties, with one String on each row. So what I intend to do is pass the appropriate data for the table to properties according to which button was pressed, and let LandmarkTableViewController display the corresponding properties.
class LandmarkTableViewController: UITableViewController {
var properties = [String]()
var passedLandmark = Landmark(name: "temp", properties: ["temp"]) // initially set to default value
override func viewDidLoad() {
super.viewDidLoad()
loadSampleProperties()
}
func loadSampleProperties() {
self.properties = passedLandmark!.properties
}
// other methods....
}
class Landmark {
var name: String
var properties: [String]
init?(name: String, properties: [String]) {
self.name = name
self.properties = properties
// Initialization should fail if there is no name or if there is no property.
if name.isEmpty || properties.isEmpty {
return nil
}
}
However, when I run the code, only temp is displayed in the table view. I've been stuck on this for a long time now, so any help is much appreciated!
Edit: loadData() inside of viewDidLoad() is changed to the correct loadSampleProperties(). I made an error while posting the code to the question.
I think this should solve your problem if not double check your identifiers
and you can make sure to data passing with adding print(passedLandmark) to viewDidLoad() or breakpoint to make sure you getting the data
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let destinationvc = segue.destinationViewController
if let landmarkvc = destinationvc as? LandmarkTableViewController {
if segue.identifier == "showLibrary" {
let library = Landmark(name: "Run Run Shaw Library", properties: ["Chinese Kanji", "Gray", "Green Plants"])
landmarkvc.passedLandmark = library
}
if segue.identifier == "showBank" {
let bank = Landmark(name: "Hang Seng Bank", properties: ["Chinese Kanji", "Green"])
landmarkvc.passedLandmark = bank
}
}
}
Hope this will helps
Code is missing from your quote, so I can't be sure, but I assume your loadData() method is the one that reloads the table view data with Landmark you've passed in prepareForSegue. If that is the case:
viewDidLoad() is called before prepareForSegue, so that all the views and elements of the destinationViewController are loaded and ready to use. Thus, in your case, the table view is loaded with your "temp" data and nothing makes it reload when you set the proper one.
You have two options:
You could call loadData()/reloadData() in viewWillAppear for example, which is called after prepareForSegue(). Bare in mind that viewWillAppear will possibly be called again in some other navigation.
Otherwise, you could instantiate and present/push the new controller in your parent view controller, instead of using the segue.
I want to make such thing:
On one ViewControleer I'm making a query to Parse.com, where I'm sending objects fields to Label.Text. By clicking one button objects randomly changes, by clicking another one- next ViewController is opening. Just imagine Tinder - on the first VC I swiping girls, on the new one chat is opening, with the girl's name in the head of the NavigatorItem
So I want to send Object Field "Name" that I'm using in that view to another without other query.
I don't know, whether I can do it via segue, or protocol. Can U somehow help me with implementation?
here is the code of my random function
func retriveJobData() {
var query: PFQuery = PFQuery(className: "Jobs")
query.getObjectInBackgroundWithId("AUeuvj0zk2") {
(newJobObject: PFObject?, error: NSError?) -> Void in
if error == nil && newJobObject != nil {
println(newJobObject)
if let newJobObject = newJobObject {
self.PrcieTextField.text = newJobObject["jobPrice"] as? String
self.DateTextField.text = newJobObject["jobDate"] as? String
self.DescriptionTextField.text = newJobObject["jobDescription"] as? String
}
} else {
println(error)
}
}
}
I want to send newJobObject["jobName"] to NavigatorItemName of another ViewController
you can override prepareForSegue for this purpose:
override func prepareForSegue(segue: UIStoryboardSegue!, sender: AnyObject!) {
if (segue.identifier == "yourSegueIdentifier") {
// pass data to next view
}
}
Assuming you have some method that triggers a push to the new viewController and that you're using the storyboard, call performSegue using the identifier you set up in the storyboard
#IBAction func buttonPressed(sender: UIButton!) {
performSegueWithIdentifier("identifier", sender: nil)
}
Then override prepareForSegue and pass in the string
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "identifier" {
let controller = segue.destinationViewController as! ViewController
controller.jobName = someWayThatYouRetrieveNewJobObjectName
}
Then in ViewController ensure you have a property for jobName
var jobName:String! //declare this as an optional instead if needed
And set the navigation title
navigationItem.title = jobName