I have a collection view where each of the cells has a delete button. I added the following code to cellForItemAt indexPath function.
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellTwo", for: indexPath) as! CustomCellTwo
cell.deleteButton.layer.setValue(indexPath.row, forKey: "index")
cell.deleteButton.addTarget(self, action: #selector(deleteCell), for: .touchUpInside)
Initially it looked as if it was working great. However, I found out that the add target function does not get called at the first tap if I scroll back and forth and then tap the delete button. If I tap again, it works as expected. Only the first tap does not work.
I have been trying to find a reason and a solution for several hours... Please help provide any ideas and advice.
Try to move buttons handling into CustomCellTwo implementation. Handle button event touchUpInside with #IBAction func. Now you can debug it with breakpoint set in this function's body.
Also add closure type variable to your CustomCellTwo to pass deleteCell calls into it. So it could also be checked with breakpoint.
Example:
class CustomCellTwo: UICollectionViewCell {
var onDelete: (() -> Void)?
#IBAction func onDeleteButtonTouch(_ sender: Any) {
onDelete?()
}
}
// in your UICollectionViewDataSource
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cellTwo", for: indexPath) as! CustomCellTwo
cell.onDelete = {
self.deleteCell(indexPath)
}
}
Related
I'm trying to allow user interaction in my collection view. I have decided to try to implement UITapGestureRecognizer to do this. I have tried adding a UITapGestureRecognizer to the collectionview itself and to the collectionview cell. Both ways crash the app. Here is how I am adding the UITapGestureRecognizer to the cell.
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionview.dequeueReusableCell(withReuseIdentifier: "userCell", for: indexPath) as! UserCell
cell.userImage.sd_setImage(with: URL(string: self.user[indexPath.row].imagePath))
cell.nameLabel.text = self.user[indexPath.row].username
cell.userID = self.user[indexPath.row].userID
let singleTap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "segueToProfile:")
singleTap.numberOfTapsRequired = 1
singleTap.numberOfTouchesRequired = 1
cell.addGestureRecognizer(singleTap)
return cell
}
When I tap on the cell I get a SIGABRT in the AppDelegate. The error message reads "terminating with uncaught exception of type NSException". What am I doing wrong. UITapGestureRecognizer.
This is my segueToProfile function:
func segueToProfile(gesture: UITapGestureRecognizer) {
// if(recognizer.state == UIGestureRecognizer.State.ended){
// print("myUIImageView has been tapped by the user.")
// }
print("hell world")
}
If you use didSelectItemAt method of collectionView your codebase look readable and maintainable.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
currentViewController.performSegue(withIdentifier: "YourSegueName", sender: nil)
}
First, I would get rid of tapgesturerecognizer as didSelectItem should handle what you are trying to accomplish. That being said, in order for this to work you must:
Remove tapgesturerecognizer
Ensure that the collection view delegate is set to self.
e.g. <yourColletionViewName>.delegate = self
Above can be assigned at viewDidLoad()
I have a collectionView showing cells. When I drag/touch/slide my finger on an item, if the touch ends on the item, the cell is selected (segues to the details screen).
Is there any way to limit cell selection (didSelectItemAt indexPath) to a simple tap? i.e it shouldn't select the cell if finger is dragged on an item and the touch ends on it.
Is this the default behavior?
I feel like it might be the cause of a cryptic issue with my custom navigation.
Thanks
Do add Following in your cellForItem
let tap = UITapGestureRecognizer(target: self, action: #selector(cellTapped(tapGestureRecognizer:)))
tap.numberOfTapsRequired = 1
cell.addGestureRecognizer(tap)
And add following function
#IBAction func cellTapped(tapGestureRecognizer: UITapGestureRecognizer)
{
//Do your required work.
}
You can use UITapGestureRecognizer, cause it will only respond on Tap gesture:
#objc func tapAction(_ sender: UITapGestureRecognizer) {
// TODO: - Action you need
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: <CellReuseId>, for: indexPath)
let tap = UITapGestureRecognizer(target: self, action: #selector(tapAction(_:)))
cell.contentView.addGestureRecognizer(tap)
return cell
}
But in this way didSelectItemAt will not work.
I have a button in a custom cell of a collectionview. The collectionview is on a scrollview. For some reason, I am not able to click on the button. I've checked that all my elements have User Interaction enabled.
Here is my layout of the collection (I've hidden some sensitive data)
Here is my custom collection view cell:
class MyCollectionViewCell: UICollectionViewCell {
#IBOutlet weak var nameLabel: UILabel!
#IBOutlet weak var connectButton: UIButton!
var onConnectTap: (MyCollectionViewCell) -> Void)?
#IBAction func connectButton(_ sender: Any) {
onConnectTap?(self)
}
func populate(_ user: User) {
nameLabel.text = user.name
}
}
I have a xib file where a Touch Up Inside event of a button has been hooked up to the connectButton IBAction.
And in my ViewController:
MyCollectionView.register(UINib(nibName: "MyCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "cell")
Here's my collection view function in my ViewController:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = myCollectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! MyCollectionViewCell
let user = users.values[indexPath.row]
cell.populate(user)
cell.onConnectTap = { (cell) in
//do something
}
return cell
}
Nothing happens when I click on the button. Am I missing something here? Is the scroll view interfering? Do I need to specifiy a addTarget? Or something else?
After searching the entire web pretty much, I finally found the solution that was in the comment of this SO answer: https://stackoverflow.com/a/44908916/406322
I needed to add this in MyCollectionViewCell:
self.contentView.isUserInteractionEnabled = false
I think the cell selection was hijacking the touch event.
I'm facing the same issue and found the best solution after spending much time.
cell.contentView.isUserInteractionEnabled = false
But its the perfect solution, and adds only one line in the cell for item method
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = myCollectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! MyCollectionViewCell
cell.contentView.isUserInteractionEnabled = false
return cell
}
Double-check the structure of the XIB file. I lost time dealing with this issue (where the button in the XIB did not seem to respond), as the structure had a second embedded cell, rather than just one (AboutCell in my case).
I have a custom button in my collection view cell. I just want to pass indexPath to it but I am getting
"unrecognized selector error"
Here is my code
cell.showMapButton.addTarget(self, action: #selector(testFunc(indexPath:)), for: .touchUpInside)
and the function is
func testFunc(indexPath: IndexPath){
print("Testing indexPath \(indexPath)")
}
If I remove the indexPath argument it works fine and the function gets called but I need that argument so please help me in resolving this issue.
In the addTarget(:action:for:) method for UIButton, the action can at most accept a single UIButton or any of it's superclass as parameter. If you need the indexPath of your button, you need to make it a property of your UIButton by subclass or other means. My way of doing it is to create a subclass of UIButton that have indexPath as it's property:
class ButtonWithIndexPath: UIButton {
var indexPath:IndexPath?
}
Then add target as normal:
cell.showMapButton.addTarget(self, action: #selector(testFunc(button:)), for: .touchUpInside)
Not forgetting to set the indexPath of your button to that of which ever cell it is in
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "myCell", for: indexPath) as! myCell
cell.button.indexPath = indexPath
...
return cell
}
And cast it into it's custom subclass in the function to read the indexPath:
func textFunc(button: UIButton) {
let currentButton = (button as! ButtonWithIndexPath)
print(currentButton.indexPath)
}
You can pass UIButton instance with target selector parameters for button action.
try with following code:
Add/replace below code, belongs to collection view cell into your collection view data source method - cellForRowAtIndexPath
cell.showMapButton.tag = indexPath.row
cell.showMapButton.addTarget(self, action: #selector(testFunc(button:)), for: .touchUpInside)
For Swift 4 - define your selector function using #objc, like below.
#objc func testFunc(button: UIBUtton){
print("Index = \(button.tag)")
}
I currently am using a Collection View to display a list of events to a user, and each one of my custom cells has a button that invites the user to attend the event. When pressed, the button image should then change to a newImage.png which displays that they are now attending that event. When I do this in my code below, pressing the button does in fact change the picture, but as I scroll down my collection view, multiple cells that have yet to be clicked also have changed to the "newImage.png." How can I stop this from happening?
class CustomCell: UICollectionViewCell{
#IBAction func myButtonAction(sender: UIButton) {
myButtonOutlet.setImage(UIImage(named: "newImage.png"), forState: UIControlState.Normal)
}
#IBOutlet weak var myButtonOutlet: UIButton!
}
The collection view is reusing cells, as it is designed to do. What you should do is reset the image in your cellForItemAtIndexPath implementation.
I've had this issue before too and this is most likely do to cell reuse. What you might try to do to avoid this problem is to explicitly set the cell's image in your cellForItemAtIndexPath() and then add something to your model that keeps track of which events the user is attending. Then, again in your cellForItemAtIndexPath(), check the model to see what button should be on that cell, and then change it accordingly.
You need to store selected button index in your class and check perticular index in your function
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! UICollectionViewCell
cell.backgroundColor = UIColor.blackColor()
if(selectedIndex == indexPath.row){
myButtonOutlet.setImage(UIImage(named: "newImage.png"), forState: UIControlState.Normal)
//change background image here also your button code
}
return cell
}
and after doing this steps . Reload collection view .
This ended up solving my problem. I have an array that I store my Cells in. Each cell has a boolean called isAttending. In my cellForItemAtIndexPath method, I implemented the code below along with the function switchImage:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
var cell = collectionView.dequeueReusableCellWithReuseIdentifier("CalendarCell", forIndexPath: indexPath) as! CalendarCell
cell.customButton.layer.setValue(indexPath.row, forKey: "index")
cell.customButton.addTarget(self, action: "switchImage:", forControlEvents: UIControlEvents.TouchUpInside)
return cell
}
func switchImage(sender: UIButton){
let index : Int = (sender.layer.valueForKey("index")) as! Int
if (events[index].isAttending == false){
events[index].isAttending = true
cell.customButton.setImage(UIImage(named: "isAttending.png"), forState: UIControlState.Normal)
}else{
events[index].isAttending = false
cell.customButton.setImage(UIImage(named: "isNotAttending.png"), forState: UIControlState.Normal)
}
self.collectionView.reloadData()
}