I have a UItabBarController (called tabBarController) composed of a number of options. I also have a UITableView, whose first row is an option that should make the user navigate to a specific viewController.
My didSelectRowAt delegate method looks something like this:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if tableView.cellForRowAt(at: indexPath)?.textLabel?.text == "Navigate to BrowseViewController" {
/* BrowseViewController is currently the second item in the
tabBarController, so I just select its index to navigate to it */
tabBarController?.selectedIndex = 2
}
}
Now, this works for my current situation because I know that the second item in tabBarController is the UIViewController that I am looking for, but I want to future-proof my app so that if the order of viewControllers in tabBarController is changed in the future, the tableView does not break.
In other words, I am wondering if there is a way to first extract the index of the viewController I am looking for from tabBarController, and then use that index to navigate to it, something like so:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if tableView.cellForRowAt(at: indexPath)?.textLabel?.text == "Navigate to BrowseViewController" {
let browseViewControllerIndex = Int()
/* iterate through tabBarController's VC's and if the type of the VC
is BrowseViewController, find its index and store it
in browseViewController */
}
}
You can try something like:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if tableView.cellForRowAt(at: indexPath)?.textLabel?.text == "Navigate to BrowseViewController" {
// safely get the different viewcontrollers of your tab bar
// (viewcontrollers is an optional value)
guard let tabs = tabBarController.viewcontrollers else { return }
// index(of:) gets you the index of the specified class type.
// Also an optional value
guard let index = tabs.index(of: BrowseViewController()) else { return }
tabBarController?.selectedIndex = index
}
}
I was able to figure this out on my own. The code below is what works best for my goals. It is reasonably concise and elegant (in my opinion):
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if tableView.cellForRowAt(at: indexPath)?.textLabel?.text == "Navigate to BrowseViewController" {
if let browseIndex = (tabBarController?.viewControllers?.filter { $0 is UINavigationController} as? [UINavigationController])?.firstIndex(where: { $0.viewControllers.first is BrowseViewController }) {
tabBarController?.selectedIndex = browseIndex
}
}
}
Note that BrowseViewController is the first viewController of UINavigationController. Of course, users looking at this answer should modify their code to suit their architecture.
Related
I have a viewController with a tableView, and another viewController that contains data that I'm trying to pass to the tableView. To add entries to the tableView I used segues, but the problem with segues is that they don't update the tableView permanently. They merely create an instance of the ViewController and add the entry there, but the original object remains unchanged. Both ViewControllers are part of a tab bar controller. What I want is to update the table permanently. Meaning, I want to be able to navigate to the viewController where the table is defined and see that's an entry has been added. Here's the code for the viewController with the tableView:
import UIKit
class FavoritesViewController: UIViewController {
public var shops = [
"hello world",
"hello world",
"hello world"
]
#IBOutlet weak var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
table.delegate = self
table.dataSource = self
table.reloadData()
}
}
extension FavoritesViewController: UITableViewDelegate, UITableViewDataSource{
func add(_ shopName: String) {
print(shopName)
shops.append(shopName)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return shops.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell",for: indexPath)
cell.textLabel?.text = shops[indexPath.row]
return cell
}
// define the action. In this case "delete"
func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
return .delete
}
// do the actual deleting
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
tableView.beginUpdates()
shops.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
tableView.endUpdates()
}
}
}
And here's how I'm trying to update (in the case adding an entry) the tableView in the other viewController:
class MainViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate{
public var shopName:String?
// there are also many other vars, but they're irrelevant
public var favoritesDestinationVC = FavoritesViewController()
// prepares the data for the segue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToFavs" {
favoritesDestinationVC = segue.destination as! FavoritesViewController
if let newShopName = shopName {
favoritesDestinationVC.shops.append(newShopName)
}
}
}
}
However, when I add the entry the to the table, the segue creates an instance of FavoritesViewController, adds that entry there, and then displays it in a popup window like this:
But when I dismiss this window the changes disappear (the tableView remains the same; 3 times "Hello World").
I want the changes to be saved in the tableView after dismissing this window. Any idea on how to do that? On how to make those changes permanent?
By your explanation, it looks like. Segue is defined as presenting FavoritesViewController modally. and this behavior is expected. By your implementation. Since you are not updating the view controller object which is part of the tab bar controller.
To make the changes in the controller in tab bar controller, Either you access that object using tabcontroller.viewcontrollers. Communicate using another way like a delegate or notification.
Edit:
It totally depends on where you want to access FavoritesViewController.
If you want to access from TabBarViewController (based on your view hierarchy it may change. be careful about index and typecasting):
let favVC = self.viewControllers?[1] as! FavoritesViewController
favVC.shops.append(newShopName)
If you want to access from a view controller which is part of same tab bar controller:
var favVC = self.tabBarController?.viewControllers?[1] as! FavoritesViewController
favVC.shops.append(newShopName)
Note: Viewcontrollers's index depends on viewcontroller order in your tab bar controller. And type casting depends upon your view hierarchy.
I am working on an small project where I have an app that takes in tvshow information entered by the user and displays it in a custom tableview cell. I would like to sort the shows as they are entered based on which current episode the user is on. I know this code works because I tested it with print statements and it sorts the array but it does not sort on the simulator. So I just was curious where I should place this so that it sorts on the app side.
func sortShows() {
let sortedShows = tvShows.sorted { $0.currentEpisode > $1.currentEpisode}
TVShowTableView.reloadData()
print(sortedShows)
}
Here is where I am currently placing it inside my view controller
extension TVShowListViewController: AddTVShowDelegate {
func tvShowWasCreated(tvShow: TVShow) {
tvShows.append(tvShow)
dismiss(animated: true, completion: nil)
TVShowTableView.reloadData()
sortShows()
}
}
In this part of your code:
func sortShows() {
// here you are creating a NEW array
let sortedShows = tvShows.sorted { $0.currentEpisode > $1.currentEpisode}
// here you tell the table view to reload with the OLD array
TVShowTableView.reloadData()
print(sortedShows)
}
In your controller class, you probably have something like:
var tvShows: [TVShow] = [TVShow]()
and then you populate it with shows, like you do with a new show:
tvShows.append(tvShow)
Then your controller is doing something like:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tvShowCell", for: indexPath) as! TVShowCell
cell.tvShow = tvShows[indexPath.row]
return cell
}
What you want to do is add another var to your class:
var sortedShows: [TVShow] = [TVShow]()
then change your sort func to use that array:
func sortShows() {
// use the existing class-level array
sortedShows = tvShows.sorted { $0.currentEpisode > $1.currentEpisode}
// here you tell the table view to reload
TVShowTableView.reloadData()
print(sortedShows)
}
and change your other funcs to use the sortedShows array:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// use sortedShows array
return sortedShows.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tvShowCell", for: indexPath) as! TVShowCell
// use sortedShows array
cell.tvShow = sortedShows[indexPath.row]
return cell
}
and you'll want to call sortShows() at the end of viewDidLoad() (or wherever you are getting your initial list of shows).
Edit
Another way you might use cellForRowAt:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "tvShowCell", for: indexPath) as! TVShowCell
// use sortedShows array
let tvShow = sortedShows[indexPath.row]
cell.showTitleLable.text = tvShow.title
cell.showDecriptionLable.text = tvShow.description
return cell
}
What I basically want is I want to press on a row in my TableViewController which then takes, for example, the text that the row has and passes it to a ViewController that is currently not present. Like when you click on a song in the Spotify app and it plays it without presenting anything but the song details are shown in the mini-player.
Does anyone have a clue how to do that?
Well you can do that but you need to initialize your View Controller first for you to access its properties like:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let vc = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "DestinationVc") as? DestinationVc
vc?.text = "TextToBePassed"
}
And there it is without presenting it but I don't get it why you don't want to present or show it but that's how it is done based on your question. Thanks :)
If you have created the UI via XIB or programatically then follow this approach:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let nextVC = NextViewController()
nextVC.text = model?[indexPath.row].text // If you are using model or if you have stored the data in the array then nextVC.text = yourArray[indexPath.row]["text"]
self.navigationController?.pushViewController(nextVC,animated: true)
}
Also, in the NextViewController, you have to add text. Like this:
class NextViewController: UIViewController {
var text = String()
//MARK:- View Life Cycle
override func viewDidLoad() {
super.viewDidLoad()
print(text) //This will print the text passed from previous VC
}
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let vc = NextViewController()
vc.title = "\(Title)"
self.navigationController?.pushViewController(vc,animated: true)
}
Using this method can help you in passing the data to another Controller without using segue.
Assuming this is for iOS as the question doesn't specify.
In the tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) method in your UITableViewDelegate, you can grab the cell's text with
let cell = tableView.cellForRow(at: indexPath)?.textLabel?.text // cell: String?
You can then assign this to a global variable if you wish, or if you maintain a reference to the non-present view controller, you can give it a property to store this text and assign it before you call performSegue(withIdentifier identifier: String, sender: Any?).
I currently have 2 table view controllers. I've added two disclosure indicators on two static cells for marital status and home state (canton). The user clicks on one of both and is taken to another view controller where he makes the appropriate selection.
The code is currently working for marital status. My question is if here I could reuse the second view controller (i.e. the one with the dynamic cells) for the same purpose but utilising a different array (in this case an array with states' names). For me it is clear that I could simply add a new view controller and implement the states' list there. Here is a screenshot of the storyboard:
First View Controller code:
import UIKit
class FirstTableViewController: UITableViewController, DataEnteredDelegate {
#IBOutlet var maritalStatusCell: UITableViewCell!
#IBOutlet var maritalStatusLabel: UILabel!
func userDidEnterInformation(info: String) {
maritalStatusLabel.text = "Marital Status: (\(info))"
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "maritalStatusSegue" {
let sendingVC: SecondTableViewController = segue.destination as! SecondTableViewController
sendingVC.delegate = self
}
}
}
Second View Controller code:
import UIKit
protocol DataEnteredDelegate {
func userDidEnterInformation(info: String)
}
class SecondTableViewController: UITableViewController {
let maritalStatusArray: [String] = ["Single", "Married"]
let cantonArray: [String] = ["ZG", "ZH", "BE", "LU", "AG"]
var delegate: DataEnteredDelegate? = nil
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return maritalStatusArray.count
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if delegate != nil {
let information: String? = tableView.cellForRow(at: indexPath)?.textLabel?.text
delegate!.userDidEnterInformation(info: information!)
dismiss(animated: true, completion: nil)
self.navigationController?.popViewController(animated: true)
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MaritalStatusCell", for: indexPath)
cell.textLabel?.text = maritalStatusArray[indexPath.row]
return cell
}
}
Does is make sense here to use the second table view controller for the states' list as well ? If yes, how can I implement that ? Thanks.
Yes you can use the Same View controller for displaying the Array of your states' names which I think you have declared in cantonArray, what you need to do is declare a bool variable in Second View Controller (In case if you want to manage only two arrays, if you want to manage more arrays then declare an enum). Then in the segue get from which index that segue is fired, you can get the selected indexPath like this
if let indexPath = tableView.indexPathForSelectedRow{
}
Now check the indexPath.row, if it is 0 then you have selected Marital State so you need to show maritalStatusArray array so make the bool variable true if you get indexpath.row = 1 then make that variable false
Now in Second View Controller add a condition as per the bool variable and show the data from that array like this
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MaritalStatusCell", for: indexPath)
if showMaritalArray {
cell.textLabel?.text = maritalStatusArray[indexPath.row]
} else {
cell.textLabel?.text = cantonArray[indexPath.row]
}
return cell
}
This is how you can declare enum
enum SelectedRow {
case MaritalStatus
case States
case ThirdRow
}
var selectedRow = SelectedRow.MaritalStatus
I'm attempting to create my first iOS app that I plan to publish into the App Store. It's a tabbed application with TableView embedded into each View Controller. Here's the code for one of my tabbed View Controllers:
import Foundation
import UIKit
class AU: UITableViewController {
var textArray = ["001", "002", "003", "004", "005", "006", "007", "008", "009", "010", "011", "012", "013", "014", "015", "016", "017", "018", "019", "020", "021", "022", "023", "024", "025", "026", "027", "028", "029", "030", "031", "032", "033", "034", "035", "036", "037", "038", "039", "040", "041", "042" ]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("AUCell") as UITableViewCell!
cell.textLabel?.text = textArray[indexPath.row]
return cell
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return textArray.count
}
}
So, basically, when the user taps on one of the items in the textArray, I want to switch to a different View Controller. I'm currently writing this in Swift 2.
Every UIViewController embedded in a UITabBarController has a reference back to the UITabBarController with its tabBarController property. To change the selected view controller of the tab bar, set the tab bar's selectedViewController:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
if (indexPath.row == 0) { // check the row that was selected
self.tabBarController?.selectedIndex = 0 // select a new tab on the tab bar, changing the selected view controller
}
}
First of all create a few ViewControllers in your main storyboard and give them storyboard ids
Create list of names :
let viewControllersNames = ["ViewController_1","ViewController_2","ViewController_3"]
and in the method :
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let vc = self.storyboard?.instantiateViewControllerWithIdentifier(self.viewControllersNames[indexPath.row])
self.navigationController?.pushViewController(vc!, animated: true)
}
Good luck !