I have a button called addSet at the end of each section of my tableView, it is used as a footerView and it is supposed to tell the UITableViewController of when it is pressed and in which section. My code for the custom table view cell is as follows
import UIKit
class FooterTableViewCell: UITableViewCell {
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
var footerDelegate:FooterTableViewCellDelegate?
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
#IBAction func addSetIsPressed(_ sender: AnyObject) {
print("Add Set is pressed")
footerDelegate?.didAddSetIsPressed(cell:self)
}
}
protocol FooterTableViewCellDelegate {
func didAddSetIsPressed(cell:FooterTableViewCell)
}
And in my TableViewController, I implement it like so
func didAddSetIsPressed(cell: FooterTableViewCell) {
let indexPath = tableView.indexPath(for: cell)
print("Index path is \(indexPath)")
}
I want to get the indexPath (the section specifically) when the user taps my button, however it always returns nil. What am I doing wrong?
To put things in context. I am using this cell as a footerView, so the cell is implemented like so
override func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
let cell = tableView.dequeueReusableCell(withIdentifier: "footerCell") as! FooterTableViewCell
cell.footerDelegate = self
return cell
}
so it isn't implemented in cellForRow at indexPath like it would normally be
Thanks in advance.
The thing is you put the cell FooterTableViewCell as a viewForFooterInSection,
so it's not used as a UITableViewCell in the UITableView, so the UITableView is not holding the indexPath of this UITableViewCell "Cause i said previously, the cell's view only is used as a footerView"
You need to add the button inside the cell that's being rendered on the UITableView. "The one that's being returned in the tableView(_:cellForRowAt:) method"
On a side note i noticed that you have a variable named footerDelegate in your cell, it needs to be weak to avoid memory leaks as you assign your TableViewController as this delegate,
so the UITableViewCell holds a strong reference of the TableViewController that leads to memory leak cause also in the view hierarchy the TableViewController contains the UITableView as a subView.
I found out how to do it, in order to detect the section in which the button was tapped. There must be an outlet reference in the FooterCell and in the tableViewController, in viewForFooter in Section, just add the following line
cell.addSetOutlet.tag = section
Related
I have a table view cell that has a button which, when clicked, shows an action view.
After reading this answer saying that the logic to show the action view should be handled in the controller.
The problem is that I use these table view cells in several different controllers and it seems counterintuitive to copy and paste the action view logic into each controller where the table view cells exist, especially considering the maintenance required.
So my question is, what is the best approach to handling this? Is there a way that I can handle all of the action view logic in a single place, and refer the controllers to that code?
Have the action for click in tableview cell and pass a variable in cellforrow so you know from which screen you are coming and accordingly handle the click.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell : RiderCell! = tableView.dequeueReusableCell( withIdentifier: "RiderCell") as! RiderCell
cell.UpdateCell(from:"Profile")
cell.selectionStyle = .none
return cell as RiderCell
}
in you table cell
import UIKit
class RiderCell: UITableViewCell {
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
}
func UpdateCell(from:String){
//manage click here
}
}
I have a MainCollectionView used for scrolling between items, inside of one of these cells I have another collectionView with cells. In that collection view, I have a button for each cell. My question is how do I pass action from my button to my MainCollectionView when it is tapped? I did create protocol for that button in the cell but I don't know how to let MainCollectionView know when my button is tapped. I can call action from my cell class but I think it is better to run it in Model which is my MainCollectionView. Below is my button protocol.
protocol ThanhCaHotTracksCellDelegate: class {
func handleSeeAllPressed()}
weak var delegate: ThanhCaHotTracksCellDelegate?
#objc func handleSeeAllButton(){
delegate?.handleSeeAllPressed()
}
LIke NSAdi said, you're on the right track, but the delegate pattern is a bit much overhead for just a single task like notifying about a button press.
I prefer using closures, because they're lightweight and helps to keep related code together.
Using Closures
This is what I'm always doing in UITableView. So this will work in UICollectionView too.
class MyTableViewCell: UITableViewCell {
var myButtonTapAction: ((MyTableViewCell) -> Void)?
#IBAction func myButtonTapped(_ sender: Any) {
myButtonTapAction?(self)
}
}
So when I dequeue my cell and cast it to MyTableViewCell I can set a custom action like this:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "myCellReuseIdentifier", for: indexPath) as! MyTableViewCell
cell.myButtonTapAction = { cell in
// Put your button action here
// With cell you have a strong reference to your cell, in case you need it
}
}
Using direct reference
When you're dequeueing your UICollectionView cell you can obtain a reference to your button by casting the cell to your cell's custom subclass.
Then just do the following
cell.button.addTarget(self, action: #selector(didTapButton(_:)), forControlEvents: .TouchUpInside)
And outside have a function:
#objc func didTapButton(_ sender: UIButton) {
// Handle button tap
}
Downside of this is that you have no direct access to your cell. You could use button.superview? but it's not a good idea since your view hierarchy could change...
You're on the right track.
Make sure MainCollectionView (or the class that contains) it implements ThanhCaHotTracksCellDelegate protocol.
Then assign the delegate as self.
Something like...
class ViewController: ThanhCaHotTracksCellDelegate {
override func viewDidLoad() {
super.viewDidLoad()
subCollectionView.delegate = self
}
}
My table view allows multiple cell selection, where each cell sets itself as selected when a button inside the cell has been clicked (similar to what the gmail app does, see picture below). I am looking for a way to let the UITableViewController know that cells have been selected or deselected, in order to manually change the UINavigationItem. I was hoping there is a way to do this by using the delegate methods, but I cannot seem to find one. didSelectRowAtIndexPath is handling clicks on the cell itself, and should not affect the cell's selected state.
The most straight forward way to do this would be to create our own delegate protocol for your cell, that your UITableViewController would adopt. When you dequeue your cell, you would also set a delegate property on the cell to the UITableViewController instance. Then the cell can invoke the methods in your protocol to inform the UITableViewController of actions that are occurring and it can update other state as necessary. Here's some example code to give the idea (note that I did not run this by the compiler, so there may be typos):
protocol ArticleCellDelegate {
func articleCellDidBecomeSelected(articleCell: ArticleCell)
func articleCellDidBecomeUnselected(articleCell: ArticleCell)
}
class ArticleCell: UICollectionViewCell {
#IBAction private func select(sender: AnyObject) {
articleSelected = !articleSelected
// Other work
if articleSelected {
delegate?.articleCellDidBecomeSelected(self)
}
else {
delegate?.articleCellDidBecomeUnselected(self)
}
}
var articleSelected = false
weak var delegate: ArticleCellDelegate?
}
class ArticleTableViewController: UITableViewController, ArticleCellDelegate {
func articleCellDidBecomeSelected(articleCell: ArticleCell) {
// Update state as appropriate
}
func articleCellDidBecomeUnselected(articleCell: ArticleCell) {
// Update state as appropriate
}
// Other methods ...
override tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueCellWithIdentifier("ArticleCell", forIndexPath: indexPath) as! ArticleCell
cell.delegate = self
// Other configuration
return cell
}
}
I would have a function like 'cellButtomDidSelect' in the view controller and in 'cellForRowAtIndexPath', set target-action to the above mentioned function
So i have userListTableViewController and userListTableViewCell in which i am connecting the followButton .. this is the code of my userListTableViewCell
import UIKit
class userListTableViewCell: UITableViewCell {
// IBOutlets..
#IBOutlet var followButton: UIButton!
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
}
func createButton(delegate:AnyObject){
followButton.addTarget(delegate, action: "followButtonTapped:", forControlEvents: UIControlEvents.TouchUpInside)
}
}
and this is my cellForRowAtIndexPath code:
myCell.createButton(self)
and this is the func of followButtonTapped in userListTableViewController
func followButtonTapped(object:AnyObject) {
println("button clicked") // ******************** here i want to know in which cell or indexPath the button is being pressed. or maybe when button is being tapped, change the title of that button.
}
I need some nice explanation where i've marked "******************". Thanks for your time.
I'm holding at any cell the NSIndexPath and assigning it at the cellForRow.
At the delegate method I'm returning the cell itself,
(see the UITableView delegate functions - they deliver the UITableView), So at the delegate function you have the relevant cell, and it has the relevant NSIndexPath.
Pay attention - if you assigning the NSIndexPath - any change of the cells like adding row or removing one will make the old NSIndexPath of the other cells to be not true...
Set the button tag to the indexPath.row in your cellForRowAtIndexPath code, and set your followButtonTapped method as an #IBAction with a UIButton parameter, rather than AnyObject
So in your cellForRowAtIndexPath add this:
myCell.followButton.tag = indexPath.row
and change your followButtonTapped method to be:
#IBAction func followButtonTapped (sender: UIButton!) {
println("\(sender.tag) button pressed")
}
You will have to connect followButtonTapped to your follow button in IB, but then should be good to go.
TableView didSelectRowAtIndexPath function is called on click of cell.
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath)
I have made a table view in iOS that displays a list of buddy (friend) requests. For the buddy request cell, I have made it a prototype cell and have given it a custom class that extends from UITableViewCell. When I click the "Accept" button on the cell, I want to remove that row from the requests array I have and remove it from the table view as well.
The three options I have considered are
1) Giving the custom cell a property for row that corresponds to the row in the table, and hence, the row in the requests array. Then, when accept is called, pass that row to the delegate function and call
requests.removeAtIndex(row)
tableView.reloadData()
which updates all the custom cells' row property. This method works. However, is this a bad practice to reload the table data (it's only reloading from the stored array, not making a network request)
2) Giving the custom cell the row property, but then calling
self.requests.removeAtIndex(row)
self.requestsTableView.beginUpdates()
self.requestsTableView.deleteRowsAtIndexPaths([NSIndexPath(forRow:row, inSection: 0)], withRowAnimation: UITableViewRowAnimation.Fade)
self.requestsTableView.endUpdates()
However, this does not update the row value in each of the cells following the deleted cell, and I would somehow either have to update them all, or call reloadData() which isn't what I want to do.
3) Instead of passing the row value, when the "Accept" button is clicked, search for the username in the buddies list, get the index of where it is found, and then delete the row in the table using that index and deleteRowsAtIndexPaths. This seems okay to do, especially since I'll never have a huge amount of buddy requests at once and searching won't require much time at all, but I figure if I had immediate access to the row value, it would make things cleaner.
Here is the code:
View Controller
class RequestsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, RequestTableViewCellDelegate
{
// Outlet to our table view
#IBOutlet weak var requestsTableView: UITableView!
let buddyRequestCellIdentifier: String = "buddyRequestCell"
// List of buddies who have sent us friend requests
var requests = [Buddy]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
self.getBuddyRequests()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: -Table View
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return requests.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: RequestTableViewCell = tableView.dequeueReusableCellWithIdentifier(buddyRequestCellIdentifier) as! RequestTableViewCell
let buddy = requests[indexPath.row]
let fullName = "\(buddy.firstName) \(buddy.lastName)"
cell.titleLabel?.text = fullName
cell.buddyUsername = buddy.username
cell.row = indexPath.row
cell.delegate = self
return cell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let buddy = self.requests[indexPath.row]
}
func didAccpetBuddyRequest(row: Int) {
// Remove buddy at the 'row' index
// idea 1: update all cells' 'row' value
//self.requests.removeAtIndex(row)
// reloading data will reload all the cells so they will all get a new row number
//self.requestsTableView.reloadData()
// idea 2
// Using row doesn't work here becuase these values don't get changed when other cells are added/deleted
self.requests.removeAtIndex(row)
self.requestsTableView.beginUpdates()
self.requestsTableView.deleteRowsAtIndexPaths([NSIndexPath(forRow:row, inSection: 0)], withRowAnimation: UITableViewRowAnimation.Fade)
self.requestsTableView.endUpdates()
// idea 3: don't use row, but search for the index by looking for the username
}
// MARK: -API
func getBuddyRequests() {
// self.requests = array of buddy requests from API request
self.requestsTableView.reloadData()
}
}
Custom UITableViewCell and protocol for the delegate call
protocol RequestTableViewCellDelegate {
func didAccpetBuddyRequest(row: Int)
}
class RequestTableViewCell: UITableViewCell {
#IBOutlet weak var titleLabel: UILabel!
#IBOutlet weak var acceptButton: UIButton!
var delegate: RequestTableViewCellDelegate?
var buddyUsername: String?
var row: Int?
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
}
#IBAction func touchAccept(sender: AnyObject) {
// <code goes here to make API request to accept the buddy request>
self.delegate?.didAccpetBuddyRequest(self.row!)
}
}
Thanks for taking the time to read this, I appreciate any help/best practices that you know that could help me in this situation.
There shouldn't be a problem with giving the cell the indexPath and delegate properties, and then informing the delegate when the Accept button has been tapped. You do need to call reloadData(), though, to update the references in the cells that are affected.
If you wish to minimise the number of reloaded rows, call reloadRowsAtIndexPaths() instead, but I think that creating the loop that creates the NSIndexPath objects will slow your app down just the same.
As an alternative I can suggest you another way:
First add action method to your acceptButton in viewController. Inside that method you can get indexPath of the cell that contains button. Here is implementation
#IBAction func acceptDidTap(sender: UIButton) {
let point = tableView.convertPoint(CGPoint.zeroPoint, fromView: button)
if let indexPath = tableView.indexPathForRowAtPoint(point) {
// here you got which cell's acceptButton triggered the action
}
}