I have been searching through many posts on SO but couldn't find an answer to this one.
I have a Table view listing various items. Each cell in the table view has a button that swaps an image around when clicked on, effectively working as an "on" or "off" button to show a user which items in the list they have selected. I have a variable inside my custom Cell Prototype class which stores a value of true or false which is updated every time the button is clicked on.
There is a "Done" button in the Table View that when tapped on calls an unwind Segue to go back to the first View Controller.
When the user taps on the Enter Table View button (on the first View Controller) to display the Table the buttons all go back to their default state, am guessing because each time the segue to the Table View Screen happens it creates a new instance of the Table to be displayed.
What I'm trying to achieve is that the state of the button (either on or off) is retained when going back into the Table screen. I've tried for a while sending an Integer value back from the TableCell Class (using a delegate) to the first View controller and then passing that value back into the Table View controller when the forward segue is called in order to have a "retained from the previous state value" that can be compared against when the cells are created to indicate if a button had been clicked or not. Couldn't get it to work though to save the state of the buttons. The list of Items in the Table will also change depending on what a user adds.
Some Screen shots and the code are below. The code hasn't got the delegate i was trying included (as it didn't work) but if its needed I will edit the post to include it. Any help would be hugely appreciated. Many Thanks!!
Code I have so far is:
//Main View Controller//
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//segue to the Table View Screen
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "EnterTableView" {
let newTableView = segue.destination as! TableViewController
}
}
// Unwind Segue Called on Exit From Table View
#IBAction func unwindToMainViewController (_segue:UIStoryboardSegue) {
}
}
// Table View Controller //
class TableViewController: UITableViewController {
var dataArray = ["A", "B", "C", "D"]
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
//create one section for table
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
//create number of rows based on the number of items in the dataArray set above
return dataArray.count
}
// an array that will contain all the cells
var cellArray = [UITableViewCell] ()
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//create a new cell based on the cell class "TableViewCell"
let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath) as? TableViewCell
// variable to contain a single element from the dataArray - updates every time a new cell is created
let dataArrayForCells = dataArray [indexPath.row]
//set cell label text to show the value from the dataArrayForCells
cell!.label.text = dataArrayForCells
cellArray.append(cell!)
return cell!
}
// Table Cell Class//
class TableViewCell: UITableViewCell {
#IBOutlet weak var label: UILabel! // label to hold display some text
#IBOutlet weak var buttonImage: UIImageView! //image for button
var buttonClicked = true //variable to contain weather the has been clicked
//if button is tapped on run the below
#IBAction func aButton(_ sender: Any) {
//if button is clicked is true, swap image to red ("on") button, set buttonClicked value to false
if buttonClicked {
buttonImage.image = #imageLiteral(resourceName: "Rec Button Red")
buttonClicked = false
}
// if buttonClicked value is false swap image to grey ("off") button set buttonClicked value back to true
else {
buttonImage.image = #imageLiteral(resourceName: "Rec Button Grey")
buttonClicked = true
}
}
I have a tableView with a custom cell that has a UITextView inside it and I want to make the UITextView of the last cell in the tableView the firstresponder when a button is pressed. However, I'm not sure how to reference that UITextView inside the cell.
It has an outlet in the custom cell class, but I don't know how to use this button (an action in another class) to reference it.
class ActionCell: UITableViewCell {
#IBOutlet weak var label: UITextView!
}
What I tried is this, but it doesn't work:
#IBAction func addAction(_ sender: Any) {
let cell = tableview.cellForRow(at: IndexPath.init(row: -1, section: 1)) as? ActionCell
let textview = cell?.contentView.subviews.filter{$0 is UITextView}
textview![0].becomeFirstResponder()
}
I have a UITextView inside each cell of a UITableView
I am using Core Data to save data which is typed in the UITextView
I would like to save the text typed in UITextView once the user is done editing it
I have added UITextViewDelegate to my TableViewCell class
I am using Notifications to post the new text to the TableViewController
I am able to get the new text to the TableViewController but I don't know how to get the row number of the cell that contained the textview wherein the text was typed. I need to know the row number (or the object in that row) to update the correct NSManagedObject.
What I have Tried:
I was thinking about using tags but since I need to constantly add and delete rows it wouldn't be the best approach
I have tried using DidSelectedRowAtIndexPath but it doesn't get triggered while the
user taps the UITextView (UITextView covers up to 80% of the one cell)
In the TableViewCell class, I have:
func textViewDidEndEditing(_ textView: UITextView) {
// Post notification
let userInfo = [ "text" : textView.text]
NotificationCenter.default.post(
name: UITextView.textDidEndEditingNotification,
object: nil,
userInfo: userInfo as [AnyHashable : Any])
}
In the TableViewController, I have:
//Subscribe
NotificationCenter.default.addObserver(self,
selector: #selector(textEditingEnded(notification:)),
name: UITextView.textDidEndEditingNotification,
object: nil)
#objc func textEditingEnded(notification:Notification) {
guard let text = notification.userInfo?["text"] as? String else {return}
print ("text: \(text)")
}
Don't hesitate to ask for more details.
I'll appreciate every bit of help I can get!
Create a property of the NSManagedObject type in the table view cell.
In Interface Builder connect the delegate of the text view to the cell.
In the controller pass the appropriate data source item in cellForRowAt to the cell.
Delete the observer and instead of posting a notification change the attribute in the NSManagedObject instance directly and save the context.
As NSManagedObject instances are reference types the changes will persist.
I hope you can have variable inside your UITableViewCell subclass for certain item
var item: Item?
then in cellForRowAt set certain item for certain cell
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = ...
...
cell.item = array[indexPath.row]
...
}
now you can implement UITextViewDelegate to your cell subclass and you can use method textViewDidEndEditing for handling when user is done with typing
class YourCell: UITableViewCell {
...
var item: Item?
...
override func awakeFromNib() {
yourTextView.delegate = self
}
}
extension YourCell: UITextViewDelegate {
func textViewDidEndEditing(_ textView: UITextView) {
... // here save text and here you can use variable `item`
}
}
I'm pulling in some JSON data and displaying it in a UITableView (iOS/iPhone 8). It displays the image, title, and description of each value. I've successfully got that down, however, are having trouble pulling the image into a separate View Controller.
By that, I mean, when a cell on the first View Controller is tapped, another view controller opens to display just the information from that cell.
I've been able to make the title and description accessible via a global variable and an indexPath. But the same won't apply to an image, due to a conflict with strings.
I've listed below what I have successfully done with the title and description strings and then show my proposition (which doesn't work of course).
How can I get an image that has already been loaded and is in an array, to be accessible like I already have with the title and description, for use in another View Controller?
The code that formats and gathers values from the JSON:
if let jsonData = myJson as? [String : Any] { // Dictionary
if let myResults = jsonData["articles"] as? [[String : Any]] {
// dump(myResults)
for value in myResults {
if let myTitle = value["title"] as? String {
// print(myTitle)
myNews.displayTitle = myTitle
}
if let myDesc = value["description"] as? String {
myNews.displayDesc = myDesc
}
if let mySrc = value["urlToImage"] as? String {
// print(mySrc)
myNews.src = mySrc
}
self.myTableViewDataSource.append(myNews)
// dump(self.myTableViewDataSource)
// GCD
DispatchQueue.main.async {
self.myTableView.reloadData()
}
}
}
}
Two variables I have outside of the class, in order to use them globally:
var petsIndex = ""
var petsDesc = ""
The code that works with the UITableView and its cells:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let myCell = tableView.dequeueReusableCell(withIdentifier: "reuseCell", for: indexPath)
let myImageView = myCell.viewWithTag(2) as! UIImageView
let myTitleLabel = myCell.viewWithTag(1) as! UILabel
myTitleLabel.text = myTableViewDataSource[indexPath.row].displayTitle
let myURL = myTableViewDataSource[indexPath.row].src
loadImage(url: myURL, to: myImageView)
return myCell
}
The code that I'm using to send the JSON values to another View Controller. I achieve this by utilizing those global variables:
// If a cell is selected, view transitions into a different view controller.
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
petsIndex = self.myTableViewDataSource[indexPath.row].displayTitle
petsDesc = self.myTableViewDataSource[indexPath.row].displayDesc
// Img needs to go here
myIndex = indexPath.row
performSegue(withIdentifier: "segue", sender: self)
}
Here's what I was doing to maybe solve my problem. I converted the string to a UIImage? or a UIImageView? and passed it as data. I left the variable empty and would change it as the data came available. That would occur, when the cell was clicked. Then inside of the second View Controller, I would utilize a an IBOutlet for the UIImageView:
// Variable outside of the class
var petsImg: UIImageView? = nil
petsImg = self.myTableViewDataSource[indexPath.row].src
I'm stumped at this point. I have gotten errors about the image being a string and needed to be converted. And when it was converted, the variable always came back is empty or nil.
Update:
I just tried doing this. It works and doesn't throw any errors. However, I still get a value of nil
petsImg = UIImage(named: self.myTableViewDataSource[indexPath.row].src)
When you perform a segue, you can intercept the call so to prepare the view controller it is showing. The view of this controller at this point has not loaded yet, and so you will need to create properties inside your PostViewController; you could create properties for the title, description, and image.
However, it will be a lot easier passing this information around as your NewsInfo object, for example:
struct NewsInfo {
let displayTitle: String
let displayDesc: String
let src: String
var imageURL: URL { return URL(string: src)! }
}
As well as a custom cell class that takes a NewsInfo object as an argument to populate the outlets.
class NewsInfoTableViewCell: UITableViewCell {
var newsInfo: NewsInfo? {
didSet {
updateOutlets()
}
}
override func prepareForReuse() {
super.prepareForReuse()
newsInfo = nil
}
private func updateOutlets() {
textLabel?.text = newsInfo?.displayTitle
detailTextLabel?.text = newsInfo?.displayDesc
// loadImage()
}
}
Setup the custom table cell class and set the newsInfo property after dequeuing.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuseCell", for: indexPath) as! NewsInfoTableViewCell
cell.newsInfo = myTableViewDataSource[indexPath.row]
return cell
}
When the cell is selected, you can pass it as the sender for performing the segue rather than setting the global variables to populate the PostViewController on viewDidLoad.
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if let cell = tableView.cellForRow(at: indexPath) as? NewsInfoTableViewCell {
performSegue(withIdentifier: "segue", sender: cell)
}
}
You can remove this whole method if you replace your existing segue by ctrl-dragging from the prototype cell to the PostViewControllerin IB to make the cell the sender of the segue.
We want this because we will intercept the segue to prepare the destination view controller by passing it the NewsInfo object of the cell that was selected and triggered the segue.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
switch (segue.destination) {
case (let controller as PostViewController, let cell as NewsInfoTableViewCell):
controller.newsInfo = cell.newsInfo
default:
break
}
}
Similar to how we pass a NewsInfo object to the cell to populate the outlets, you can do the same thing for the PostViewController.
Quick and dirty solution
In your second view controller load the image using:
// With petsImg being the url to your image:
if let url = URL(string: petsImg), let imageData = Data(contentsOf: url) {
imagePost.image = UIImage(data: data)
}
Proper solution
You should not work with global variables to pass data from one view controller to another (read why). Rather look at this question's answer to find out how to transfer data (in your case: the myNews object) from the table view to a detail view:
Send data from TableView to DetailView Swift
If this is too abstract, you can look at this tutorial. It covers what you want to do: https://www.raywenderlich.com/265-uisplitviewcontroller-tutorial-getting-started
It looks like your image is not an image but a url to an image. You can load images into image views using a library like nuke: https://github.com/kean/Nuke
Since network requests are called asynchronously, its a bit difficult to see at which point you're trying to configure your UIImageView. But once you have your network response you will do one of the two:
If your view controller is not yet loaded, (ie you load it once your network response is complete) you can configure the UIImageView in the prepare for sequel method.
If your view controller is already loaded (which is perfectly fine), you will need to set a reference to that view controller in the prepare for segue method. Then you can configure the view controller once the network request is made. I would make the reference to that VC weak, as the system (navigation stack) is already holding on to the VC strongly.
PS: I suggest you de-serialize your JSON response to an object. It will go a long way to help us understand your code. It's hard to see your issue when you're passing dictionary objects around. I suggest you use one of the following:
1. Codable protocol
2. ObjectMapper
3. MapCodableKit (this one is my library which I use personally)
PPS: I assumed you use storyboards.
So I have a button that looks like a pencil in a collection view cell xib.
Then I have this code.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "groupsCollectionViewCellIdentifier", for: indexPath) as! GroupCollectionViewCell
//add action to the edit button
cell.editButton.tag = indexPath.row
cell.editButton.addTarget(self, action: #selector(GroupsCollectionViewController.editGroupAction), for: .touchUpInside)
return cell
}
//segue to edit group
func editGroupAction() {
performSegue(withIdentifier: "editGroupSegue", sender: self)
}
But whenever I click the edit button. Nothing is happening. I wonder what's missing.
I spent hours scouring the web for a solution to my UIButton's inside UICollectionView's not working. Driving me nuts until I finally found a solution that works for me. And I believe it's also the proper way to go: hacking the hit tests. It's a solution that can go a lot deeper (pun intended) than fixing the UICollectionView Button issues as well, as it can help you get the click event to any button buried under other views that are blocking your events from getting through:
UIButton in cell in collection view not receiving touch up inside event
Since that SO answer was in Objective C, I followed the clues from there to find a swift solution:
http://khanlou.com/2018/09/hacking-hit-tests/
--
When I would disable user interaction on the cell, or any other variety of answers I tried, nothing worked.
The beauty of the solution I posted above is that you can leave your addTarget's and selector functions how you are used to doing them since they were most likey never the problem. You need only override one function to help the touch event make it to its destination.
Why the solution works:
For the first few hours I figured the gesture wasn't being registered properly with my addTarget calls. It turns out the targets were registering fine. The touch events were simply never reaching my buttons.
The reality seems to be from any number of SO posts and articles I read, that UICollectionView Cells were meant to house one action, not multiple for a variety of reasons. So you were only supposed to be using the built in selection actions. With that in mind, I believe the proper way around this limitation is not to hack UICollectionView to disable certain aspects of scrolling or user interaction. UICollectionView is only doing its job. The proper way is to hack the hit tests to intercept the tap before it gets to UICollectionView and figure out which items they were tapping on. Then you simply send a touch event to the button they were tapping on, and let your normal stuff do the work.
My final solution (from the khanlou.com article) is to put my addTarget declaration and my selector function wherever I like (in the cell class or the cellForItemAt override), and in the cell class overriding the hitTest function.
In my cell class I have:
#objc func didTapMyButton(sender:UIButton!) {
print("Tapped it!")
}
and
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
guard isUserInteractionEnabled else { return nil }
guard !isHidden else { return nil }
guard alpha >= 0.01 else { return nil }
guard self.point(inside: point, with: event) else { return nil }
// add one of these blocks for each button in our collection view cell we want to actually work
if self.myButton.point(inside: convert(point, to: myButton), with: event) {
return self.myButton
}
return super.hitTest(point, with: event)
}
And in my cell class init I have:
self.myButton.addTarget(self, action: #selector(didTapMyButton), for: .touchUpInside)
Try this one on your cell
cell.contentView.isUserInteractionEnabled = false
Considering your problem I have created a demo with the details you have provided above with some minor changes.
I have modified your cellForItem method. My modified version is as below.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell : GroupCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "groupsCollectionViewCellIdentifier", for: indexPath) as! GroupCollectionViewCell
cell.editButton.tag = indexPath.row
cell.editButton.addTarget(self, action: #selector(editGroupAction(sender:)), for: .touchUpInside)
return cell
}
And the action method is written as below:
func editGroupAction(sender: UIButton) {
print("Button \(sender.tag) Clicked")
}
From your code I have modified below Details:
1) Way of declaration of UICollectionViewCell Object.
2) Way of Assigning #Selector Method to the UIButton. And at the last
3) In the action method I have print the Button tag.
With the above Changes I am getting proper result. I got the selected Index value as button tag, as assigned in code in consol. The output I am getting is as below.
Button 2 Clicked
Button 3 Clicked
Button 4 Clicked
I hope this will work for your requirement.
I was having the same issue and after using the View hierarchy, I have noticed that an additional UIView was added to the cell.
This view was above my UIButton, so touch event was not passed down to the button, the didSelectItem was triggered instead.
I solved this by using the following call:
cell.bringSubviewToFront(cell.button)
Now the event will be called.
To enable touch action on the UIButton of your Custom UICollectionCell, add the below method in your Custom UICollectionCell class.
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
var view = myButton.hitTest(myButton.convert(point, from: self), with: event)
if view == nil {
view = super.hitTest(point, with: event)
}
return view
}
If you have to cover a number of buttons, here's a way to write the same code:
class SomeCell: UICollectionViewCell {
#IBOutlet var drawButton: UIButton?
#IBOutlet var buyButton: UIButton?
#IBOutlet var likeButton: UIButton?
#IBOutlet var sayButton: UIButton?
// fix crazy Apple bug in collection view cells:
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
if let drawButton = drawButton, let v = drawButton.hitTest(
drawButton.convert(point, from: self), with: event) {
return v
}
if let buyButton = buyButton, let v = buyButton.hitTest(
buyButton.convert(point, from: self), with: event) {
return v
}
if let likeButton = likeButton, let v = likeButton.hitTest(
likeButton.convert(point, from: self), with: event) {
return v
}
// etc ...
return super.hitTest(point, with: event)
}
}
I realize this ticket is pretty old, but I had the same problem, and found a different solution.
I ran Xcode with the view-debugger. While the button was sized correctly, it's superview had a width of 0 points. This would make it impossible to tap on this button, or any other subviews.
Just mentioning this, as it might be worth trying out.
If you declare your buttons programmatically you need to make sure they are set as lazy var objects to ensure self is fully defined first, before the button is initialised.
class myCell: UICollectionViewCell {
static let identifier = "myCellId"
lazy var myButton: UIButton = {
let btn = UIButton()
btn.addTarget(self, action: #selector(handleButtonPress(_:)), for .touchUpInside)
return btn
}()
// rest of cell
}
Are you assign the class to the cell and link the button with controller and also assign the identifier to the segue and also use break point to check if the func is call or not
and use segue like this
func editGroupAction() {
performSegue(withIdentifier: "editGroupSegue", sender: self)
let src = self.sourceViewController as UIViewController
let dst = self.destinationViewController as UIViewController
src.navigationController.pushViewController(dst, animated:false)
}
If you are using iOS 10.Following is working code
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
let cell = collectionView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! YourCellClass
cell.btnJoin.tag = (indexPath as NSIndexPath).row
cell.btnJoin.addTarget(self, action: #selector(YourViewControllerClassName.doSomething(_:)), for: UIControlEvents.touchUpInside)
}
Action
func doSomething(_ sender: UIButton) {
print("sender index",sender.tag)
}
By the way, I had to implement the hit test solution then I had this issue below:
I had a similar problem where my one of my buttons was working while another one towards the bottom of the cell was not working and it was inside a stack view. So after many hours of looking around, I found that one of the parent views (between the button and the CollectionView itself) was having a size less than the size of its subviews which in this case the touches were not reported at all since they were happening outside of the parent view... Fixed that and it's working like a charm...
To be more specific I used a compositional layout for my collection view and the view called "_UICollectionViewOrthogonalScrollerEmbeddedScrollView" which is a wrapper for the collectionView cells and the estimated size was smaller than the cell it self