I have an UICollectionView and I want to add pan gesture to its Cells/Items. When I add the gesture in usual way UICollectionView is not getting scrolled.
This is how I add the gesture
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell:UICollectionViewCell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(CaptureViewController.pagesCollectionViewItemPanEvent(_:)))
cell.addGestureRecognizer(panGesture)
return cell;
}
Is there something wrong here? Can someone please tell me a way to get my work done. Any help would be highly appreciated.
You should add the gesture to the collection view and not to the cell itself.
Something like...
let panGesture = UIPanGestureRecognizer(target: self, action: "handlePanGesture:")
collectionView.addGestureRecognizer(panGesture)
func handlePanGesture(gesture: UIPanGestureRecognizer) {
let locationInView = gesture.locationInView(collectionView)
...
}
Just a proposal, I didn't test it:
Create a custom cell:
class PanCell: UICollectionViewCell {
override func awakeFromNib() {
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(self.pagesCollectionViewItemPanEvent(_:)))
self.addGestureRecognizer(panGesture)
}
}
and you can use the delegation to inform CaptureViewController.
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 want to add a tap gesture to every cell in a UITableView that edits the content in it. The two ways to add a gesture are in code or through storyboard. I tried both and they failed.
Can I add a gesture to every cell in table with storyboard drag and drop? It seems to only add gesture to the first cell. Adding gesture in code, I wrote something like,
addGestureRecognizer(UITapGestureRecognizer(target: self,action:#selector(MyTableViewCell.tapEdit(_:))))
or
addGestureRecognizer(UITapGestureRecognizer(target: self, action:"tapEdit:"))
both work. But I'd like to let the UITableViewController handle this gesture because it does something with the datasource. How do I write my target and action?
EDIT:
addGestureRecognizer(UITapGestureRecognizer(target: MasterTableViewController.self, action:#selector(MasterTableViewController.newTapEdit(_:)))
it induce an error said, unrecognized selector sent to class 0x106e674e0...
To add gesture to UITableViewCell, you can follow the steps below:
First, add gesture recognizer to UITableView
tapGesture = UITapGestureRecognizer(target: self, action: #selector(tableViewController.tapEdit(_:)))
tableView.addGestureRecognizer(tapGesture!)
tapGesture!.delegate = self
Then, define the selector. Use recognizer.locationInView to locate the cell you tap in tableView. And you can access the data in your dataSource by tapIndexPath, which is the indexPath of the cell the user tapped.
func tapEdit(recognizer: UITapGestureRecognizer) {
if recognizer.state == UIGestureRecognizerState.Ended {
let tapLocation = recognizer.locationInView(self.tableView)
if let tapIndexPath = self.tableView.indexPathForRowAtPoint(tapLocation) {
if let tappedCell = self.tableView.cellForRowAtIndexPath(tapIndexPath) as? MyTableViewCell {
//do what you want to cell here
}
}
}
}
It is possible to add gesture directly to TableView cell and access the datasource in viewController, You need to set up a delegate:
In your custom cell:
import UIKit
class MyTableViewCell: UITableViewCell {
var delegate: myTableDelegate?
override func awakeFromNib() {
super.awakeFromNib()
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(MyTableViewCell.tapEdit(_:)))
addGestureRecognizer(tapGesture)
//tapGesture.delegate = ViewController()
}
func tapEdit(sender: UITapGestureRecognizer) {
delegate?.myTableDelegate()
}
}
protocol myTableDelegate {
func myTableDelegate()
}
In your viewController:
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UIGestureRecognizerDelegate, myTableDelegate {
#IBOutlet var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
// Do any additional setup after loading the view, typically from a nib.
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 35
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as? MyTableViewCell
cell?.delegate = self
return cell!
}
func myTableDelegate() {
print("tapped")
//modify your datasource here
}
}
However, this method could cause problems, see UIGestureRecognizer and UITableViewCell issue. In this case, when the swipe gesture successes, the selector get called twice for some reason. I can't say the second method is a bad one as I haven't found any direct evidence yet, but after searching through Google, it seems like the first method is the standard way.
You don't need to add gesture recognizer to achieve what you are doing.
Use the UITableViewDelegate method tableView:didSelectRowAtIndexPath: to detect which row is tapped (this is what exactly your tapGesture is going to do) and then do your desired processing.
If you don't like the gray indication when you select cell, type this in your tableView:didEndDisplayingCell:forRowAtIndexPath: just before returning the cell:
cell?.selectionStyle = .None
Adding gesture in awakeFromNib method seems much more easier and works fine.
class TestCell: UITableViewCell {
override func awakeFromNib() {
super.awakeFromNib()
let panGesture = UIPanGestureRecognizer(target: self,
action: #selector(gestureAction))
addGestureRecognizer(panGesture)
}
#objc func gestureAction() {
print("gesture action")
}
}
The easiest way to do this is to add the gesture in a custom UITableViewCell. An easier alternative to setting up a custom delegate pattern is to inform the view controller of the edits would be to use a handler in the form of a closure that the view controller can provide and which is called when user editing is finished. I'm assuming a textField is used to allow cell editing.
class CustomTableViewCell: UITableViewCell {
func activateTitleEditing() {
textField.isEnabled = true
textField.becomeFirstResponder()
}
// This will hold the handler closure which the view controller provides
var resignationHandler: (() -> Void)?
#objc private func tap(_ recognizer: UITapGestureRecognizer) {
guard recognizer.state == .ended else { return }
activateTitleEditing()
}
#IBOutlet weak var textField: UITextField! { didSet {
textField.delegate = self
let tap = UITapGestureRecognizer(target: self, action: #selector(tap(_:)))
addGestureRecognizer(tap)
textField.isEnabled = false
}}
}
extension CustomTableViewCell: UITextFieldDelegate {
func textFieldDidEndEditing(_ textField: UITextField) {
resignationHandler?()
}
}
And within your custom UITableViewController, pass in the handler to be able to make changes to your model. Don't forget to account for possible memory cycles in the closure.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// initialize and return table view cell
let cell = tableView.dequeueReusableCell(withIdentifier: K.documentCellIdentifier, for: indexPath)
assert(cell is CustomTableViewCell, "Document cell dequeuing error")
let customCell = cell as! DocumentTableViewCell
customCell.textField.text = documentModel.documents[indexPath.row]
customCell.resignationHandler = { [weak self, unowned customCell] in
guard let self = self else { return }
if let newTitle = customCell.textField.text {
self.cellModel.cells[indexPath.row] = newTitle
}
}
return customCell
}
I have several tap gestures being created and recognized on different UIViews from in my TableViewController and the different gestures are being recognized correctly. As seen in this code:
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("CustomCell", forIndexPath: indexPath) as! CustomCell
let tapOnView1 = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
let tapOnView2 = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
cell.View1.addGestureRecognizer(tapOnView1)
cell.View1.userInteractionEnabled = true
cell.View2.addGestureRecognizer(tapOnView1)
cell.View2.userInteractionEnabled = true
return cell
}
My Handle tap looks like this:
func handleTap(sender:UITapGestureRecognizer) {
let tappedView = sender.view
self.tableView.beginUpdates()
if tappedView == cell.View1 {
print("View 1 Tapped")
} else if tappedView == cell.View2 {
print("View 2 Tapped")
}
}
I wanted to move all this code to my CustomCell UITableViewCell class as there are actually several more UIViews that have different actions that need to be taken on a tap. Additionally moving them all to the Cell itself seems to me to be the right thing to do. I searched for answers but the only true answer I have seen is to use buttons and there are several reasons that this is really not an option for me without some serious refactoring and rewriting. I have tried several iterations to the following code in my CustomCell class:
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
let tapOnView1 = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
addGestureRecognizer(tapOnView1)
let tapOnView2 = UITapGestureRecognizer(target: self, action: Selector("handleTap:"))
addGestureRecognizer(tapOnView2)
}
and this handleTap function:
func handleTap(sender: UITapGestureRecognizer) {
if delegate != nil && item != nil {
if sender.view == view1 {
print("view1 tapped")
} else {
print("view2 tapped")
}
}
}
The tap for view1 is never called. It only ever calls the view2 tap no matter where in the cell I tap. I have tried using different Selector functions (i.e. handleTapOne: for View1, and handleTapTwo: for View2) but I can't seem to figure out how to do this.
Again it works in my UITableViewController but it does not work when I try to move all of the tap recognizers to the UITableViewCell.
Thanks for the help.
iphonic answered my question above. I was an idiot I guess. staring at a problem for two long and missing the most simplest of things.
I want to add a tap event to my CollectionViewCell and to pass there my cell with the data it has. How can I achieve this?
Should this event be handled by my ViewController or by CollectionViewCell?
My ViewController:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "CollectionViewCell", for: indexPath) as! CollectionViewCell
cell.imgImage.image = imageArray[indexPath.row]
cell.url = "xhini"
return cell
}
My CollectionViewCell:
class CollectionViewCell: UICollectionViewCell {
#IBOutlet weak var imgImage: UIImageView!
var url: String = "url"
}
Implement UICollectionViewDelegate and then you can use following method in the ViewController to react to selecting a cell:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let image = imageArray[indexPath.row]
// do stuff with image, or with other data that you need
}
Don't forget to set the delegate where you set a data source:
collectionView.dataSource = self
// add this line:
collectionView.delegate = self
UPDATE
Or if you are using a storyboards, you want to set it using storyboards the same way as you set a dataSource for the dataSource of the tableView:
UPDATE 2
Your tap gesture recognizer cancels event for the collection view, so to deal with this, just uncomment the line tap.cancelsTouchesInView = false, and it will work:
//Looks for single or multiple taps.
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(ViewController.dismissKeyboard))
//Uncomment the line below if you want the tap not not interfere and cancel other interactions.
tap.cancelsTouchesInView = false
view.addGestureRecognizer(tap)
I saw your code which you shared in the above answer by #Milan and figured out the reason.
You have added a tap gesture on viewDidLoad of ViewController :
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(ViewController.dismissKeyboard))
view.addGestureRecognizer(tap)
This makes the UICollectionView's didSelectItemAt not getting called.
So comment this code and it should work.
For this gesture, you have to find another approach