I have a table view with automaticDimension for height and 2 cells.
One cell has a read more button, which updates the layout constraint constant for a label (as IBOutlet). It works fine and the cell height updates depending on the label height, but when I try to update the layout constraint first time on cellForRowAt method delegate it works, but after that it stops working from the read more button (and the layout constraint outlet doesn't become nil).
if cellType == .movie {
let movieCell = cell as! MovieDescriptionCell
movieCell.updateCellWith(movie: selectedMovie!)
movieCell.infoLabelHeight.constant = 200. ***(here is the problem, if I don't have this the read more button works)***
movieCell.readMorePressedBlock = { [weak self] (tag) in
guard let strongSelf = self else { return }
DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(70), execute: {
strongSelf.tableView.reloadData()
})
}
}
#IBOutlet var infoLabelHeight: NSLayoutConstraint!
#IBAction func onReadMoreButton(button: UIButton) {
self.readMoreState = !self.readMoreState
setReadMoreImageFor(state: readMoreState)
let infoText = self.infoLabel.text
let expectedHeight = infoText?.height(withConstrainedWidth: infoLabelWidth.constant, font: self.infoTextFont) ?? self.infoDefaultHeight
self.infoLabelHeight.constant = self.readMoreState ? expectedHeight : self.infoDefaultHeight
readMorePressedBlock?(button.tag)
}
How can I make this work? If I delete the line "movieCell.infoLabelHeight.constant = 200" the read more button works, but I need to set the constant at the beginning too.
Thanks.
I found a solution, if I set the layout constraint in awakeFromNib method the read more button works (the possibility to change the constraint again)
override func awakeFromNib() {
super.awakeFromNib()
self.infoLabelHeight.constant = 200
}
Related
I have a ProductVC.swift (ProductViewController) file and a ProductCell.swift. The ProductVC contains a UICollectinView and ProductCell is a specific UICollectionViewCell.
ProductCell.xib looks like this:
ProductVC contains an array with all the cell data (products) and populates the cells.
My goal: The user should have the possibility to like an product. He can do it by clicking the like button on the top right corner of every cell. Every cell shows a specific product which is specified by a productID.
My Problem: The like button action (IBAction func) is in the ProductCell. ProductCell doesn´t have the cell data. Cell data is stored in ProductVC in an array. So I don´t know how catch the product(productID) the user wants to like.
My Tries: With the code below I can get the indexPath of the cell where the user clicked the like button. But I can´t use this indexPath to get the product data because the data is stored in ProductVC. I could also store the data in ProductCell but it is not a clean way. Is it possible mb to give this indexPath to the ProductVC?
extension UICollectionView {
func indexPathForView(_ view: UIView) -> IndexPath? {
let center = view.center
let viewCenter = self.convert(center, from: view.superview)
let indexPath = self.indexPathForItem(at: viewCenter)
return indexPath
}
}
let superview = self.superview as! UICollectionView
if let indexPath = superview.indexPathForView(button) {
print(indexPath) // indexPath of the cell where the button was pressed
}
SOLVED Solution is a callback closure:
//UICollectionViewCell
var saveProductLike: ((_ index: Int) -> Void)?
#IBAction func likedButtonClicked(_ sender: UIButton) {
print("Liked button clicked!")
let productArrayIndex = calculateProductArrayIndex(for: sender)
saveProductLike?(productArrayIndex!)
}
//UIViewController
cell.saveProductLike = { (index) -> Void in
print(index)
}
There are several approaches to solve this but I'll talk about the most common one which is using delegation.
protocol ProductCellDelegate: AnyObject {
func productCellDidPressLikeButton(_ cell: ProductCell)
}
in ProductCell define a property weak var delegate: ProductCellDelegate? and in the target action of the like button inform your delegate
#objc private likeButtonPressed(_ sender: Any) {
delegate?.productCellDidPressLikeButton(self)
}
In your view controller you could conform to the protocol and implement it like this:
func productCellDidPressLikeButton(_ cell: ProductCell) {
guard let ip = collectionView.indexPath(for: cell) else { return }
// process event, get product via index...
}
Then you need to set the view controller to be the delegate in collectionView(_:willDisplay:forItemAt:) or
collectionView(_:cellForItemAt:): cell.delegate = self.
I have buttons in the storyboard that I put into a Referencing Outlet Collection. I'm using UITapGestureRecognizer and UILongPressGestureRecognizer for all of these buttons, but how can I print exactly which button gets tapped? Bellow is what I tried but doesn't work. I get an error that says "Value of type 'UILongPressGestureRecognizer' has no member 'tag'." I'm trying to build the button grid for the Minesweeper game. Thank you for your help.
class ViewController: UIViewController {
#IBOutlet var testButtons: [UIButton]! // There are 100 buttons in this array
override func viewDidLoad() {
super.viewDidLoad()
let testButtonPressed = UILongPressGestureRecognizer(target: self, action: #selector(testPressed))
testButtonPressed.minimumPressDuration = 0.5
// These indexes are just to test how to recognize which button gets pressed
testButtons[0].addGestureRecognizer(testButtonPressed)
testButtons[1].addGestureRecognizer(testButtonPressed)
}
#objc func testPressed(_ sender: UILongPressGestureRecognizer) {
print("Test button was pressed")
print(sender.tag) // THIS DOESN'T WORK, BUT CONCEPTUALLY THIS IS WHAT I WANT TO DO
}
This error occurs because UILongPressGestureRecognizer object has no tag property
You can access sender's button in a way like that:
#objc func testPressed(_ sender: UILongPressGestureRecognizer) {
guard let button = sender.view as? UIButton else { return }
print(button.tag)
}
I think that the best solution to handle button's actions is to add #IBAction
(you can add it like #IBOutlet with a minor change - set Action connection type)
And then in #IBAction block you cann access all button properties (like tag and others)
instead of using gesture I think it would be better to use #IBAction and connect the buttons With it here is a small example
UILongPressGestureRecognizer which is a subclass of UIGestureRecognizer, can be used only once per button or view. Because UILongPressGestureRecognizer has only a single view property. In your code, it will always be testButtons[1] calling the testPressed action. So you have to first modify the viewDidLoad code like this :-
for button in testButtons {
let testButtonPressed = UILongPressGestureRecognizer(target: self, action: #selector(testPressed))
testButtonPressed.minimumPressDuration = 0.5
button.addGestureRecognizer(testButtonPressed)
button.addGestureRecognizer(testButtonPressed)
}
Then you can access the button from testPressed like this (I hope you've already set the tag in the storyboard) :-
#objc func testPressed(_ sender: UILongPressGestureRecognizer) {
if sender.state == .began {
if let button = sender.view as? UIButton {
print(button.tag)
}
}
}
You need to set tags before pressing!
On the viewDidLoad() method you must add something like:
testButtons.enumerated().forEach {
let testButtonPressed = UILongPressGestureRecognizer(target: self, action: #selector(testPressed))
testButtonPressed.minimumPressDuration = 0.5
$0.element.addGestureRecognizer(testButtonPressed)
$0.element.tag = $0.offset
}
And when the long press is receiving you need to get a tag from view not from the sender!
print(sender.view?.tag)
Since a gesture recognizer should only be associated with a single view, and doesn't directly support using an identity tag to match it with buttons. When creating an array of buttons for a keyboard, with a single gesture response function, I found it easier to use the gesture recognizer "name" property to identify the associated button.
var allNames: [String] = []
// MARK: Long Press Gesture
func addButtonGestureRecognizer(button: UIButton, name: String) {
let longPrssRcngr = UILongPressGestureRecognizer.init(target: self, action: #selector(longPressOfButton(gestureRecognizer:)))
longPrssRcngr.minimumPressDuration = 0.5
longPrssRcngr.numberOfTouchesRequired = 1
longPrssRcngr.allowableMovement = 10.0
longPrssRcngr.name = name
allNames.append(name)
button.addGestureRecognizer(longPrssRcngr)
}
// MARK: Long Key Press
#objc func longPressOfButton(gestureRecognizer: UILongPressGestureRecognizer) {
print("\nLong Press Button => \(String(describing: gestureRecognizer.name)) : State = \(gestureRecognizer.state)\n")
if gestureRecognizer.state == .began || gestureRecognizer.state == .changed {
if let keyName = gestureRecognizer.name {
if allNames.contains(keyName) {
insertKeyText(key: keyName)
} else {
print("No action available for key")
}
}
}
}
To implement, call the addButtonGestureRecognizer function after creating the button, and provide a name for the button (I used the button text) e.g.
addButtonGestureRecognizer(button: keyButton, name: buttonText)
The button name is stored in the "allNames" string array so that it can be matched later in "longPressOfButton".
When the button name is matched in the "longPressOfButton" response function, it passes it to "addKeyFunction" where it is processed.
I have got a simple view in swift and put 9 buttons as a 3x3 grid onto it, now i need the tag for each button and don't know how to get each button so I can get the tag property using a for loop. Does anyone know how i can get the button? Is there a function to get a view at a specified location?
Frankenstein's answer with .subviews works fine, but you can even do it more swifter using the built-in function viewWithTag(_:):
override func viewDidLoad() {
super.viewDidLoad()
// ...
// targeted view must have been added to the subview by now
if let taggedView = view.viewWithTag(1) {
print("Got the view!")
}
// you can even try to cast directly
if let taggedButton = view.viewWithTag(1) as? UIButton {
print("Got the button!")
}
// if you insist on using a for loop, you could use it like this
let highestTag = 10
for i in 0...highestTag {
if let taggedButton = view.viewWithTag(i) as? UIButton {
// here you go
}
}
}
For both approaches keep in mind, that the view you're looking for has already been added as a subview beforehand, otherwise you won't be able to search for it
You can use the subviews property of UIView and loop through each subview to check for tag you need:
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
for subview in view.subviews {
if subview.tag == 1, let button = subview as? UIButton {
print("Got the button I need.")
}
}
if let button = view.viewWithTag(1) as? UIButton {
print("Got the button I need.")
}
}
}
Update: You can also use viewWithTag to find you view with a particular tag from within your subviews.
Im trying to get tableview cells with auto resizing images to work. Basically I want the image width in the cell to always be the same, and the height to change in accordance with the aspect ratio of the image.
I have created a cell class, which only has outlets for a label, imageView and a NSLayoutConstraint for the height of the image. I have some async methods to download an image and set it as the image for the cell imageView. Then the completion handle gets called and I run the following code to adjust the height constraint to the correct height:
cell.cellPhoto.loadImageFromURL(url: photos[indexPath.row].thumbnailURL, completion: {
// Set imageView height to the width
let imageSize = cell.cellPhoto.image?.size
let maxHeight = ((self.tableView.frame.width-30.0)*imageSize!.height) / imageSize!.width
cell.cellPhotoHeight.constant = maxHeight
cell.layoutIfNeeded()
})
return cell
And here is the UIImageView extension I wrote which loads images:
func loadImageFromURL(url: String, completion: #escaping () -> Void) {
let url = URL(string: url)
makeDataRequest(url: url!, completion: { data in
DispatchQueue.main.async {
self.image = UIImage(data: data!)
completion()
}
})
}
And the makeDataRequest function which it calls:
func makeDataRequest(url: URL, completion: #escaping (Data?) -> Void) {
let session = URLSession.shared
let task = session.dataTask(with: url, completionHandler: { data, response, error in
if error == nil {
let response = response as? HTTPURLResponse
switch response?.statusCode {
case 200:
completion(data)
case 404:
print("Invalid URL for request")
default:
print("Something else went wrong in the data request")
}
} else {
print(error?.localizedDescription ?? "Error")
}
})
task.resume()
}
This works for all the cells out of frame, but the imageviews in the cells in the frame are small. Only when I scroll down and then back up again do they correctly size. How do I fix this? I know other people have had this issue but trying their fixes did nothing.
I had to sorta recreate the problem to understand what was going on. Basically you need to reload the tableview. I would do this when a picture finishes downloading.
In the view controller that has the table view var. Add this to the viewDidLoad() function.
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
//Create a notification so we can update the list from anywhere in the app. Good if you are calling this from an other class.
NotificationCenter.default.addObserver(self, selector: #selector(loadList), name: NSNotification.Name(rawValue: "loadList"), object: nil)
}
//This function updates the cells in the table view
#objc func loadList(){
//load data here
self.tableView.reloadData()
}
Now, when the photo is done downloading, you can notify the viewcontroller to reload the table view by using the following,
func loadImageFromURL(url: String, completion: #escaping () -> Void) {
let url = URL(string: url)
makeDataRequest(url: url!, completion: { data in
DispatchQueue.main.async {
self.image = UIImage(data: data!)
completion()
//This isn't the best way to do this as, if you have 25+ pictures,
//the list will pretty much freeze up every time the list has to be reloaded.
//What you could do is have a flag to check if the first 'n' number of cells
//have been loaded, and if so then don't reload the tableview.
//Basically what I'm saying is, if the cells are off the screen who cares.
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "loadList"), object: nil)
}
})
}
Heres something I did to have better Async, see below.
My code as follows, I didn't do the resizing ratio thing like you did but the same idea applies. It's how you go about reloading the table view. Also, I personally don't like writing my own download code, with status code and everything. It isn't fun, why reinvent the wheel when someone else has done it?
Podfile
pod 'SDWebImage', '~> 5.0'
mCell.swift
class mCell: UITableViewCell {
//This keeps track to see if the cell has been already resized. This is only needed once.
var flag = false
#IBOutlet weak var cellLabel: UILabel!
#IBOutlet weak var cell_IV: UIImageView!
override func awakeFromNib() { super.awakeFromNib() }
}
viewController.swift (Click to see full code)
I'm just going to give the highlights of the code here.
//Set the image based on a url
//Remember this is all done with Async...In the backgorund, on a custom thread.
mCell.cell_IV.sd_setImage(with: URL(string: ViewController.cell_pic_url[row])) { (image, error, cache, urls) in
// If failed to load image
if (error != nil) {
//Set to defult
mCell.cell_IV.image = UIImage(named: "redx.png")
}
//Else we got the image from the web.
else {
//Set the cell image to the one we downloaded
mCell.cell_IV.image = image
//This is a flag to reload the tableview once the image is done downloading. I set a var in the cell class, this is to make sure the this is ONLY CALLED once. Otherwise the app will get stuck in an infinite loop.
if (mCell.flag != true){
DispatchQueue.main.asyncAfter(deadline: .now() + 0.025){ //Nothing wrong with a little lag.
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "loadList"), object: nil)
mCell.flag = true
}
}
}
}
I have a tableView with dynamic cells with multiple TextViews. I am dismissing a keyboard with a "Cancel" and trying to determine which TextView is being dismissed to "undo" the changes made by user.
Based on this similar question: How to determine which textfield is active swift I have adapted one of the answers for the following extension:
extension UIView {
var textViewsInView: [UITextView] {
return subviews
.filter ({ !($0 is UITextView) })
.reduce (( subviews.compactMap { $0 as? UITextView }), { summ, current in
return summ + current.textViewsInView
})
}
var selectedTextView: UITextView? {
return textViewsInView.filter { $0.isFirstResponder }.first
}
}
This is working and I am presently testing in the following code:
#objc func cancelButtonAction() {
if let test = tableView.selectedTextView {
print("View Found")
}
tableView.beginUpdates()
tableView.endUpdates()
}
Doing a break at print("View Found") I can inspect "test". The following is the result.
This appears to only identify the view Test by a memory address. My question is how do I interpret this to identify the view that was being edited?
Update: There seems to be some issue in understanding. Assume I have a table with two cells and in each cell two textViews (dynamic cells). Assume the table loads by saying in the 4 textViews. "Hi John", "Hi Sam", "Bye John", "Bye Sam". Suppose the user starts editing a cell and changes one cell to read "Nachos". Then the user decides to cancel. I want to then replace with the value that was there before (from my model). I can find the textView but it now reads "Nachos". Therefore I do not know which textView to reload with the appropriate Hi and Bye.
Implement a placeholder for your textviews so that when their text is empty, it will have a default value. Therefore, when a user presses cancel while in focus of a textview, we can set the textview's text to its default value. See link to implement a textview placeholder.. Text View Placeholder Swift
I did solve this problem by adding the .tag property to the textView objects. I also dropped the extension approach and used textView delegate. The solution required me to first assign the tag and delegate = self for each textView in the tableView: cellForRowAt. The following shows one TextView of many. Notice the tag is setup so I may determine the section and the row it came from and the specific item.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
...
cell.directionsTextView.delegate = self
cell.directionsTextView.tag = indexPath.section*1000 + indexPath.row+1
return cell
}
Two global variables are defined in my tableView class:
var activeTextView = UITextView()
var activeTextViewPresentText = String()
The textViewDidBeginEditing captures the original state of the textView text before the user starts editing.
// Assign the newly active textview to store original value and original text
func textViewDidBeginEditing(_ textView: UITextView) {
print("textView.tag: \(textView.tag)")
self.activeTextView = textView
self.activeTextViewPresentText = textView.text
}
Lastly, if the user cancels the editing, the original text is reloaded.
#objc func cancelButtonAction() {
if activeTextView.text != nil {
activeTextView.text = activeTextViewPresentText
}
self.view.endEditing(true)
tableUpdate()
}