I need the tableView to perform reloadData() after a row has been added via a textView. My tableViews all use the reusable code which works fine.
Below is my Reusable TableViewCode.
class ReusableSubtitleTable: NSObject, UITableViewDataSource, UITableViewDelegate{
let cell = "cell"
var dataArray = [String]()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) {
print("DataArray count from table view = \(dataArray.count)")
return dataArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let selfSizingCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! SelfSizingCell
let num = indexPath.row
selfSizingCell.titleText.text = (stepText[num])
selfSizingCell.subtitleText.text = dataArray[num]
return selfSizingCell
}
}
The function below uses the reusable code to display the table which works fine.
class DetailViewController: UIViewController {
let step = 13
var tableView: UITableView!
let dataSource = ReusableSubtitleTable()
var selectedEntry: JournalEntry!
var dataModel = [String]()
var didSave = false
var coreDataManager = CoreDataManager()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = dataSource
tableView.dataSource = dataSource
dataSource.dataArray = dataModel
#IBAction func unwindToDetail( _ sender: UIStoryboardSegue) {
dataModel[10] = step11
didSave = coreDataManager.updateEntry(step11: step11, selectedEntry: selectedEntry)
}
}
The problem come in when a user wants to add to the last row. The user taps a button and is taken to the next controller which is a TextView. When user finishes their entry they tap the 'Save' button which returned to the DetailViewController via an unwind. The selectedEntry is saved and the dataModel updated. Now the table view needs to reload to display this added text.
I've tried adding tableView.ReloadData() after didSave. I've tried a Dispatch and tried saving the data before returning from the textView via the unwind but that doesn't work either.
I tried adding the below function to ReusableTableView and called it after the coredata update - there are no errors but it does not reload the table.
func doReload(){
tableView.reloadData()
}
I have verified that the data is saved and it does displays if I return to the summary controller and then go forward the DetailViewController.
Any help is appreciated.
Placing the UITableView reloadData() within either viewWillAppear or viewDidAppear should resolve this issue.
For example:
func viewDidAppear(_ animated: bool) {
super.viewDidAppear(animated)
tableView.reloadData()
}
This is because the view hierarchy isn't yet regarded as "visible" during the segue unwind and why you see it work by going back to reloading the view controller. The reloadData() function, for efficiency, only redisplays visible cells and at the time of the unwind the cells aren't "visible".
Apple Documentation - UITableView.reloadData():
For efficiency, the table view redisplays only those rows that are
visible.
I'm creating a quiz app with custom cells that include a label of questions and then an answer coming from a UISegmentedControl.
The values of the segmentedcontrols get changed when scrolling and this leads to an inaccurate score. I understand that this is due to UITableView reusing cells.
My tableview's datasource in my main vc is simply the labels for all my questions coming from a plist file.
The code for my custom tableviewcell class is
class QuestionsTableViewCell: UITableViewCell {
#IBOutlet weak var questionLabel: UILabel!
#IBOutlet weak var selection: UISegmentedControl!
var question: String = "" {
didSet {
if (question != oldValue) {
questionLabel.text = question
}
}
}
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
//Just for testing
#IBAction func segmentChanged(_ sender: UISegmentedControl) {
print("value is ", sender.selectedSegmentIndex);
}
}
where the View is stored in an .XIB file.
And the code for my main vc is
class ViewController: UIViewController, UITableViewDataSource {
let questionsTableIdentifier = "QuestionsTableIdentifier"
#IBOutlet var tableView:UITableView!
var questionsArray = [String]();
var questionsCellArray = [QuestionsTableViewCell]();
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let path = Bundle.main.path(forResource:
"Questions", ofType: "plist")
questionsArray = NSArray(contentsOfFile: path!) as! [String]
tableView.register(QuestionsTableViewCell.self,
forCellReuseIdentifier: questionsTableIdentifier)
let xib = UINib(nibName: "QuestionsTableViewCell", bundle: nil)
tableView.register(xib,
forCellReuseIdentifier: questionsTableIdentifier)
tableView.rowHeight = 108;
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return questionsArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(
withIdentifier: questionsTableIdentifier, for: indexPath)
as! QuestionsTableViewCell
let rowData = questionsArray[indexPath.row]
cell.question = rowData
return cell
}
#IBAction func calculate(_ sender: UIButton) {
var score = 0
for cell in tableView.visibleCells as! [QuestionsTableViewCell] {
score += cell.selection.selectedSegmentIndex
}
let msg = "Score is, \(score)"
print(msg)
}
#IBAction func reset(_ sender: UIButton) {
for cell in tableView.visibleCells as! [QuestionsTableViewCell] {
cell.selection.selectedSegmentIndex = 0;
}
}
}
What I'd like to do is just keep track of all 'selection' changes of the Questions cells in an array, and then use that array in cellForRowAt. I'm just confused as to how i can dynamically keep track of changes from a view in another class. I'm new to Swift and would like to solve this is a proper MVC fashion. Thanks
Instead of a simple string array as data source create a class holding the text and the selected index
class Question {
let text : String
var answerIndex : Int
init(text : String, answerIndex : Int = 0) {
self.text = text
self.answerIndex = answerIndex
}
}
Declare questionArray as
var questions = [Question]()
Populate the array in viewDidLoad with
let url = Bundle.main.url(forResource: "Questions", withExtension: "plist")!
let data = try! Data(contentsOf: url)
let questionsArray = try! PropertyListSerialization.propertyList(from: data, format: nil) as! [String]
questions = questionsArray.map {Question(text: $0)}
In the custom cell add a callback and call it in the segmentChanged method passing the selected index, the property question is not needed, the label is updated in cellForRow of the controller
class QuestionsTableViewCell: UITableViewCell {
#IBOutlet weak var questionLabel: UILabel!
#IBOutlet weak var selection: UISegmentedControl!
var callback : ((Int) -> ())?
#IBAction func segmentChanged(_ sender: UISegmentedControl) {
print("value is ", sender.selectedSegmentIndex)
callback?(sender.selectedSegmentIndex)
}
}
In cellForRow add the callback and update the model in the closure
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: questionsTableIdentifier, for: indexPath) as! QuestionsTableViewCell
let question = questions[indexPath.row]
cell.questionLabel.text = question.text
cell.selection.selectedSegmentIndex = question.answerIndex
cell.callback = { index in
question.answerIndex = index
}
return cell
}
To reset the segmented controls in the cells set the property in the model to 0 and reload the table view
#IBAction func reset(_ sender: UIButton) {
questions.forEach { $0.answerIndex = 0 }
self.tableView.reloadData()
}
Now you could calculate the score directly from the model instead of the view.
Don't try to use cells to hold information. As the user scrolls through your table view, cells that scroll out of view will get recycled and their field settings will be lost. Also, newly dequeued cells will have the settings from the last time they were used.
You need to refactor your code to read/write information into a data model. Using an array of Structs as a data model is a reasonable way to go. (Or, as vadian suggests in his answer, and array of Class objects, so you get reference semantics.)
You have an IBAction segmentChanged() in your custom cell class. The next trick is to notify the view controller when the user changes the selection, and to update cells when you set them up in cellForRowAt.
I suggest defining a protocol QuestionsTableViewCellProtocol, and have the view controller conform to that protocol:
protocol QuestionsTableViewCellProtocol {
func userSelected(segmentIndex: Int, inCell cell: UITableViewCell)
}
}
Add a delegate property to your QuestionsTableViewCell class:
class QuestionsTableViewCell: UITableViewCell {
weak var delegate: QuestionsTableViewCellProtocol?
//The rest of your class goes here...
}
Update your cell's segmentChanged() method to invoke the delegate's userSelected(segmentIndex:inCell:) method.
In your view controller's cellForRowAt, set the cell's delegate to self.
func userSelected(segmentIndex: Int, inCellCell cell: UITableViewCell) {
let indexPath = tableView.indexPath(for: cell)
let row = indexPath.row
//The code below assumes that you have an array of structs, `dataModel`, that
//has a property selectedIndex that remembers which cell is selected.
//Adjust the code below to match your actual array that keeps track of your data.
dataModel[row].selectedIndex = segmentIndex
}
Then update cellforRowAt() to use the data model to set the segment index on the newly dequeued cell to the correct index.
Also update your calculate() function to look at the values in your dataModel to calculate the score, NOT the tableView.
That's a rough idea. I left some details out as "an exercise for the reader." See if you can figure out how to make that work.
There's a button in another ViewController, if I press on it, I should see the time when I pressed on the button.
The button works, but the table won't refresh after I click on a refresh button, place the refresh on the ViewDidAppear function doesn't work as well.
I need to quit the app, close it from multitasking and open it again, then the time that I pressed on the button shows. What should I do to make the refresh button work?
(Both View Controllers are in the same storyboard, the second one extends the first one)
First View Controller:
class Tracking: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var activity: UITableView!
var activities = [String]()
var userData = false
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return activities.count
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "cell")
cell.textLabel?.text = activities[indexPath.row]
return(cell)
}
#IBAction func Reload(_ sender: AnyObject) {
activity.reloadData()
}
.
.
.
}
Second view controller:
class Activity: Tracking {
.
.
.
#IBAction func playButton(_ sender: AnyObject) {
isPlayed += 1
userData = true
UserDefaults.standard.set(userData, forKey: "userData")
let playElm = playStr + " בשעה: " + getTime()
activities.append(playElm)
UserDefaults.standard.set(activities, forKey: "activities")
}
.
.
.
}
You need to fetch from user defaults your new date in activities array and after that you can reloadData
#IBAction func Reload(_ sender: AnyObject) {
self.activities = UserDefaults.standard.get( forKey: "activities")
activity.reloadData()
}
When you call activity.reloadData(), you're telling the table view to update its rows and what they display based solely on the contents of your activities property that you defined with the line:
var activities = [String]()
When you're loading the app from a fresh start, that activities array of strings hasn't been filled with anything. I see you save data to UserDefaults, but I don't see anywhere from which you read it.
Put this next code in your viewDidLoad(). viewDidAppear() isn't what you want to use for this purpose.
activities = UserDefaults.standard.get(forKey: "activities")
activity.reloadData()
I managed to get this working automaticlly without the refresh button. The code that Svetoslav Bramchev wrote works when I place it in viewDidAppear. Thanks for your help!
override func viewDidLoad() {
super.viewDidLoad()
userData = UserDefaults.standard.bool(forKey: "userData")
if(userData == true){
activities = UserDefaults.standard.object(forKey: "activities") as! [String]
} else {
activities.append("no data")
UserDefaults.standard.set(activities, forKey: "activities")
if(activities[0] == "no data"){
activities.remove(at: 0)
UserDefaults.standard.set(activities, forKey: "activities")
}
}
}
override func viewDidAppear(_ animated: Bool) {
activities = UserDefaults.standard.object(forKey: "activities") as! [String]
activity.reloadData()
}
I have two table views. One which the user clicks on and one where data is displayed. When the user clicks on a cell in the first table view a query is made to my firebase database and the query is stored in an Array. I then pass the data through a segue. I used a property observer so I know that the variable is being set. By using break points I was able to determine that my variable obtains its value right before the cellForRowAtIndexPath method. I need help displaying the data in my table view. I do not know where to reload the data to get the table view to update with my data. I am using Swift.
EDIT 2: I have solved my problem. I will post my first and second table views so that you can see my solution.
FirstTableView
import UIKit
import Firebase
import FirebaseDatabase
class GenreTableViewController: UITableViewController {
let dataBase = FIRDatabase.database()
var genreArray = ["Drama","Classic,Comic/Graphic novel","Crime/Detective","Fable,Fairy tale","Fantasy","Fiction narrative", "Fiction in verse","Folklore","Historical fiction","Horror","Humour","Legend","Magical realism","Metafiction","Mystery","Mythology","Mythopoeia","Realistic fiction","Science fiction","Short story","Suspense/Thriller","Tall tale","Western,Biography","Autobiography","Essay","Narrative nonfiction/Personal narrative","Memoir","Speech","Textbook","Reference book","Self-help book","Journalism", "Religon"]
var ResultArray: [NSObject] = []
var infoArray:[AnyObject] = []
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return genreArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
// Configure the cell...
cell.textLabel?.text = genreArray[indexPath.row]
return cell
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
let DestViewController: ResultTableViewController = segue.destinationViewController as! ResultTableViewController
if segue.identifier == "letsGo" {
if let indexPath = self.tableView.indexPathForSelectedRow {
let tappedItem = self.genreArray[indexPath.row]
DestViewController.someString = tappedItem
}
}
}
}
import UIKit
import Firebase
import FirebaseDatabase
class ResultTableViewController: UITableViewController {
let dataBase = FIRDatabase.database()
var SecondResultArray: [FIRDataSnapshot]! = []
var someString: String?{
didSet {
print("I AM A LARGE TEXT")
print(someString)
}
}
override func viewDidLoad() {
let bookRef = dataBase.reference().child("books")
bookRef.queryOrderedByChild("Genre")
.queryEqualToValue(someString)
.observeSingleEventOfType(.Value, withBlock:{ snapshot in
for child in snapshot.children {
self.SecondResultArray.append(child as! FIRDataSnapshot)
//print(self.ResultArray)
}
dispatch_async(dispatch_get_main_queue()) {
self.tableView.reloadData()
}
})
super.viewDidLoad()
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return SecondResultArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell2", forIndexPath: indexPath)
// Configure the cell...
let bookSnapShot: FIRDataSnapshot! = self.SecondResultArray[indexPath.row]
let book = bookSnapShot.value as! Dictionary<String, String>
let Author = book["Author"] as String!
let Comment = book["Comment"] as String!
let Genre = book["Genre"] as String!
let User = book["User"] as String!
let title = book["title"] as String!
cell.textLabel?.numberOfLines = 0
cell.textLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping
cell.textLabel?.text = "Author: " + Author + "\n" + "Comment: " + Comment + "\n" + "Genre: " + Genre + "\n" + "User: " + User + "\n" + "Title: " + title
let photoUrl = book["bookPhoto"], url = NSURL(string:photoUrl!), data = NSData(contentsOfURL: url!)
cell.imageView?.image = UIImage(data: data!)
return cell
}
}
For better context and troubleshooting here is my current code for the tableView which is supposed to display data:
import UIKit
class ResultTableViewController: UITableViewController {
var SecondResultArray: Array<NSObject> = []{
willSet(newVal){
print("The old value was \(SecondResultArray) and the new value is \(newVal)")
}
didSet(oldVal){
print("The old value was \(oldVal) and the new value is \(SecondResultArray)")
self.tableView.reloadData()
}
}
override func viewDidLoad() {
print ("I have this many elements\(SecondResultArray.count)")
super.viewDidLoad()
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return SecondResultArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell2", forIndexPath: indexPath)
cell.textLabel?.text = SecondResultArray[indexPath.row] as? String
return cell
}
}
Edit:
Here is my first table view controller. I have tried using the completion handler, but I can't call it correctly and I am constricted by the fact that my query happens in the didSelectRowAtIndexPath method. Please help.
import UIKit
import Firebase
import FirebaseDatabase
class GenreTableViewController: UITableViewController {
let dataBase = FIRDatabase.database()
var genreArray = ["Drama","Classic,Comic/Graphic novel","Crime/Detective","Fable,Fairy tale","Fantasy","Fiction narrative", "Fiction in verse","Folklore","Historical fiction","Horror","Humour","Legend","Magical realism","Metafiction","Mystery","Mythology","Mythopoeia","Realistic fiction","Science fiction","Short story","Suspense/Thriller","Tall tale","Western,Biography","Autobiography","Essay","Narrative nonfiction/Personal narrative","Memoir","Speech","Textbook","Reference book","Self-help book","Journalism", "Religon"]
var ResultArray: [NSObject] = []
var infoArray:[AnyObject] = []
override func viewDidLoad() {
super.viewDidLoad()
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = false
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return genreArray.count
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
cell.textLabel?.text = genreArray[indexPath.row]
return cell
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
typealias CompletionHandler = (result:NSObject?, error: NSError?) -> Void
func getData(completionHandeler: CompletionHandler){
let bookRef = self.dataBase.reference().child("books")
let GenreSelector = self.genreArray[indexPath.row]
bookRef.queryOrderedByChild("Genre")
.queryEqualToValue(GenreSelector)
.observeSingleEventOfType(.Value, withBlock:{ snapshot in
for child in snapshot.children {
print("Loading group \((child.key!))")
self.ResultArray.append(child as! NSObject)
}
print(self.ResultArray)
self.performSegueWithIdentifier("letsGo", sender: self)
self.tableView.reloadData()
})
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
var DestViewController: ResultTableViewController = segue.destinationViewController as! ResultTableViewController
DestViewController.SecondResultArray = self.ResultArray
}
You can inject the data to the destination viewController in prepareForSegue Method of the first UIViewController and reload your UITableView in viewDidAppear. If you are getting your data asynchronously, have a completionHandler and reload it in the completionHandler. Here is an example.
func fetchDataWithCompletion(response: (NSDictionary?, error:NSError?)-> Void) -> Void {
//make the API call here
}
How about this:
Assume you have an array (myArray) populated from Firebase and stored in the first tableViewController. There's a second tableViewController and a segue connecting them.
We want to be able to tap on an item in the first tableviewController, have the app retrieve detailed data for the item from Firebase (a 'data' node) and display the detailed data in the second tableViewController.
Firebase structure
some_node
child_node_0
data: some detailed data about child_node_0
child_node_1
data: some detailed data about child_node_1
Within the second tableViewContoller:
var passedObject: AnyObject? {
didSet {
self.configView() // Update the view.
}
}
Tapping an item in the first tableView calls the following function
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showListInSecondTable" {
if let indexPath = self.tableView.indexPathForSelectedRow {
let tappedItem = myArray[indexPath.row] as! String
let keyOfTappedItem = tappedItem.firebaseKey //child_node_0 for example
doFirebase(keyOfTappedItem)
}
}
}
and the prepareForSegue then calls the following which loads the data from firebase and when the snapshot returns within the block, it populates the passedObject property in the second tableView
func doFirebase(firebaseKey: String) {
ref = myRootRef.childByAppendingPath("\(firebaseKey)/data")
//if we want the detailed data for child_node_0 this would resolve
// to rootRef/child_node_0/data
ref.observeSingleEventOfType(.Value, { snapshot in
let detailObjectToPass = snapshot.Value["data"] as! NSArray or string etc
let controller = (segue.destinationViewController as! UINavigationController).myViewController as! SecondViewController
controller.passedObject = detailObjectToPass
}
and of course in secondController, setting the passedArray calls didSet and sets up the view, and tells the tableView to reload itself, displaying the passed array.
func configView() {
//set up the view and buttons
self.reloadData()
}
I did this super quick so ignore the typos's. The pattern is correct and satisfies the question. (and eliminates the need for an observer to boot!)
P.S. this is way over coded but I wanted to demonstrate the flow and leveraging the asynchronous call to firebase to load the second tableView when the data was valid within the block.
Try updating your closure to include this:
dispatch_async(dispatch_get_main_queue()) {
self.tableView.reloadData()
}
Edit:
On second read, you are already using a completion handler, but I think you didn't see it. Let me correct your code above a bit:
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let bookRef = self.dataBase.reference().child("books")
let GenreSelector = self.genreArray[indexPath.row]
bookRef.queryOrderedByChild("Genre")
.queryEqualToValue(GenreSelector)
.observeSingleEventOfType(.Value, withBlock:{ snapshot in
// This here is your completion handler code!
// I assume it is called asynchronously once your DB is done
for child in snapshot.children {
print("Loading group \((child.key!))")
self.ResultArray.append(child as! NSObject)
}
print(self.ResultArray)
self.performSegueWithIdentifier("letsGo", sender: self)
// self.tableView.reloadData() // is this really needed
})
}
}
You defined a closure, but simply didn't call it. I don't see a reason for that anyways, assuming the block gets called once the database gives you your results. Am I missing something?
That's a good start already, but I think you didn't entirely get how to use a completion handler in this regard, but of course I may be wrong.
I built on top of user3861282's answer and created a small demo project at my github.
In short: You can do all inter-table-communication in the prepareForSegue: method of your first table view controller. Configure the second table view controller there (via its vars). Not any closures/completion handlers there yet.
Then in the second view controller's viewWillAppear: method, start the loading (including an animation if you want). I suggest something like NSURLSession that already defines a completion handler. In that you work with your data from remote, stop any loading animations and you're good.
If the completion handler must be defined in the first table view controller, you can even set it as a var in the second table view controller. That way you "hand over" the closure, i.e. "piece of code".
Alternatively, you can start animations and remote request in the first table view controller and then performSegueWithIdentifier once that is done. In your question you wrote that you want to load in the second table view controller, however, if I understood you correctly.
Your code above properly defines a closure that expects a completion handler (which is also a closure and so kind of doubles what you want), but you never actually call it somewhere. Nor do you call the completion handler in the closure. See my demo for how it can work.
The project I wrote illustrates just one way to do it (minus animations, not enough time). It also shows how you can define your own function expecting a completion handler, but as I said, the standard remote connections in the framework provide one anyways.
Based on additional code that was added to the post, the issue is a controller variable going out of scope.
So here's the issue
class MyClass {
func setUpVars {
let x = 1
}
func doStuff {
print(x)
}
}
Create a class and attempt to print the value of x
let aClass = MyClass()
aClass.setUpVars
aClass.doStuff
This will print nothing (conceptually) as once setUpVars ended, the 'x' variable went out of scope.
whereas
class MyClass {
var x: Int
func setUpVars {
x = 1
}
func doStuff {
print(x)
}
}
will print the value of x, 1.
So the real solution is that your viewControllers need to 'stay alive' during the duration of your class (or app).
Here's the pattern. In the MasterViewController
import UIKit
class MasterViewController: UITableViewController {
var detailViewController: DetailViewController? = nil
then in your MasterViewController viewDidLoad (or wherever), create the detailViewController
override func viewDidLoad() {
super.viewDidLoad()
let controllers = split.viewControllers //this is from a splitViewController
self.detailViewController =
controllers[controllers.count-1].topViewController as? DetailViewController
}
and from there you have it... use prepareForSegue to 'send' the data to the detailViewController
Just wanted to have this posted for future reference.
You can reload the TableView with [tableView reloadData];.
There are two ViewControllers in the app. The first one has a WebView and a Navigation Bar on top, the second one is a TableView to show URLs visited. Please see screenshots and codes. After I clicked Save button to save current URL user is visiting, the TableView is empty. I have tested the TableView first, it is set up fine. Please help to find out the problem. By the way, var savedURLs = [String]( I didn't put the other half of bracket as it won't show correctly if I put it.)
import UIKit
class BrowserViewController: UIViewController {
#IBOutlet weak var browser: UIWebView!
#IBAction func saveButtonPressed(sender: AnyObject) {
if let currentURL = browser.request?.URL?.absoluteString {
savedURLs.append(currentURL)
NSUserDefaults.standardUserDefaults().setObject(savedURLs, forKey: "savedURLs")
}
}
override func viewDidLoad() {
super.viewDidLoad()
let url = NSURL(string: "https://www.google.com")!
let request = NSURLRequest(URL: url)
browser.loadRequest(request)
}
}
import UIKit
var savedURLs = [String](
class SavingViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var savingTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
savingTableView.delegate = self
savingTableView.dataSource = self
if NSUserDefaults.standardUserDefaults().objectForKey("savedURLs") != nil {
savedURLs = NSUserDefaults.standardUserDefaults().objectForKey("savedURLs") as! [String]
}
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return savedURLs.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("SavingCell")
cell!.textLabel?.text = savedURLs[indexPath.row]
return cell!
}
override func viewDidAppear(animated: Bool) {
savingTableView.reloadData()
}
}
Please check the currentURL is not nil. Because of empty currentURL your tableview is empty.
I suggest you to Saved the urls in NSuserdefault after webview loading finished completely. Hope this will help you.
I think you should add this function:
func reloadTable() {
if NSUserDefaults.standardUserDefaults().objectForKey("savedURLs") != nil {
savedURLs = NSUserDefaults.standardUserDefaults().objectForKey("savedURLs") as! [String]
}
savingTableView.reloadData()
}
And call that one instad of savingTableView.reloadData()
Also debug the code by printing the value of variables at some points. For example the new data when you read from NSUserDefaults and the value of savedURLs in viewDidAppear.
If that doesn't work make sure you're using the right cell identifier:
let cell = tableView.dequeueReusableCellWithIdentifier("SavingCell")
Try passing the data to the next view controller when you click on send button rather than using NSUserDefaults.
Maintain an array by appending the URLs that you visit, then pass it to the next view controller when you click on send.