Im using UIcollection view as my tabbar
when I scroll collection view horizontally previous selected cell will not deselect when i select new one
this is my code to change colour when i select a cell and deselect a cell
var selectedIndexPath : IndexPath = []
func collectionView(_ collectionView: UICollectionView,
didSelectItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath) as?
BottomCollectionViewCell {
cell.contentView.backgroundColor = UIColor.orange
cell.backgroundColor = UIColor.orange
}
if let preViousSelectedcell = collectionView.cellForItem(at:
selectedIndexPath) as? BottomCollectionViewCell {
preViousSelectedcell.contentView.backgroundColor=UIColor.purple
preViousSelectedcell.backgroundColor = UIColor.purple
}
selectedIndexPath = indexPath
}
while scrolling cells are reused that time cellForItemAt will call so you need to change some modification in your code
func collectionView(_ collectionView: UICollectionView,
didSelectItemAt indexPath: IndexPath) {
selectedIndexPath = indexPath
YOUR_COLLECTION_VIEW.reloadData()
}
and add below lines inside your collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath)
if indexPath == selectedIndexPath {
cell.contentView.backgroundColor=UIColor.purple
cell.backgroundColor = UIColor.purple
} else {
cell.contentView.backgroundColor = UIColor.orange
cell.backgroundColor = UIColor.orange
}
Hope this will help you
Related
How to change the color of view in collection view when it select and when the select the other view before view came to original color How to set it?
You can use the didSelectItemAtIndexPath method and the didDeselectItemAtIndexPath method from the UICollectionViewDelegate protocol. UICollectionViewDelegate is an Objective-C protocol, indicated by #objc, that allows you to have optional methods like didSelectItemAtIndexPath and didDeselectItemAtIndexPath that you can choose to implement optionally in your delegate.
When UICollectionView gets instantiated initially, it goes through all the available methods you've implemented in the instance of UICollectionViewDelegate with responds(to:), which takes a selector parameter and returns a bool, to see which methods from the UICollectionViewDelegate protocol you've implemented without actually sending a message to them. As it detects the following methods, it remembers them and calls those methods whenever you select or deselect a cell from the collection view:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
if let indexPaths = collectionView.indexPathsForSelectedItems, let firstIndex = indexPaths.first {
cell.backgroundColor = firstIndex == indexPath ? .white : .gray
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath) {
cell.backgroundColor = .white
}
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
guard let cell = collectionView.cellForItem(at: indexPath) else {
return
}
cell.backgroundColor = .gray
}
Alternatively, you can use the collectionView(_:didHighlightItemAt:) method and the collectionView(_:didUnhighlightItemAt:) method. The following sample code is from here:
func collectionView(_ collectionView: UICollectionView, didHighlightItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath) {
cell.contentView.backgroundColor = #colorLiteral(red: 1, green: 0.4932718873, blue: 0.4739984274, alpha: 1)
}
}
func collectionView(_ collectionView: UICollectionView, didUnhighlightItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath) {
cell.contentView.backgroundColor = nil
}
}
You can simply add two methods for changing colour of the view or cell in the collectionView:-
//When cell got selected
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath){
cell.backgroundColor = .green
}
}
//When cell deselected
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
if let cell = collectionView.cellForItem(at: indexPath){
cell.backgroundColor = .clear
}
}
If you have view inside your cell as backgroundView then you can use same functions and just need to replace cell.backgroundView.backgroundColor in place of the cell.backgroundColor. Just remember "backgroundView" is the name of the view you have inside cell.
If you want more information about this then you can follow below attached links:-
1). https://www.tutorialfor.com/questions-296884.html
2). https://en.it1352.com/article/fccf358a040b4ddba872d7324602754c.html
I have a variabel selectedIndexPath, which gets the indexPath selected from previous view controller. I am getting the required backgroundColor for cell in the collection view of present view controller. But when I select another cell in the collection view, the selected cell of previous view controller remains same without being deselected. So, now I have two cells with the background color. Following is my code
var selectedIndexPath = IndexPath()
override func viewDidLoad() {
super.viewDidLoad()
self.collectionView.allowsMultipleSelection = false
self.collectionView.allowsSelection = true
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! TestCollectionViewCell
if (indexPath == selectedIndexPath)
{
cell.backgroundColor = UIColor.white
}
else
{
cell.backgroundColor = UIColor.clear
}
collectionView.allowsMultipleSelection = false
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
{
let cell = collectionView.cellForItem(at: indexPath)
cell?.backgroundColor = UIColor.white
collectionView.allowsMultipleSelection = false
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath)
{
let cell = collectionView.cellForItem(at: indexPath)
cell?.backgroundColor = UIColor.clear
collectionView.allowsMultipleSelection = false
}
How do I deselect the cell in cellForItemAt, when I select new cell in didSelectItemAt. Thanks in advance.
First of all set allowsMultipleSelection in Interface Builder and remove all redundant occurrences of setting it in code
You have to update the selectedIndexPath variable. Manipulating the cell directly is always a bad idea.
Reloading the cells is much more reliable.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
{
guard selectedIndexPath != indexPath else { return }
let indexPathsToUpdate = [selectedIndexPath, indexPath]
selectedIndexPath = indexPath
tableView.reloadRows(at: indexPathsToUpdate, with: .none)
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath)
{
guard selectedIndexPath == indexPath else { return }
selectedIndexPath = IndexPath()
tableView.reloadRows(at: [indexPath], with: .none)
}
There is only one problem: If you want to have an empty selection you have to declare selectedIndexPath as optional and handle it properly.
First of all, you don't need to override didDeselect for this. All you need to do is deselect the previously selected item while selecting the current item in didSelectItem. For that you can choose to maintain states in the cell as:
func changeToSelectedState() {
self.backgroundColor = UIColor.white
}
func changeToUnselectedState() {
self.backgroundColor = UIColor.clear
}
Or you can choose to write the same in the controller itself. And then you need to perform the deselection and selection in the following manner.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath)
{
let previousSelectedCell = collectionView.cellForItem(at: selectedIndexPath)
previousSelectedCell.changeToUnselectedState()
let currentCell = collectionView.cellForItem(at: indexPath)
currentCell.changeToSelectedState()
selectedIndexPath = indexPath
}
I am attempting to highlight the background of a cell when a user selects it.
I have been successful in changing the border of a cell when a user selects it.
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
addToList.append(objectsArray[indexPath.row])
let cell = collectionView.cellForItem(at: indexPath)
cell?.contentView.layer.borderWidth = 2.0
cell?.contentView.layer.borderColor = UIColor.gray.cgColor
}
I have not been able to change the background though.
Can this be done?
Thanks!
For cell border, use cell contentView like this:
cell?.contentView.layer.borderWidth = 2.0
cell?.contentView.layer.borderColor = UIColor.gray.cgColor
And for cell backgroundColor color you need to use:
cell?.backgroundColor = .gray
Try this.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at: indexPath)
cell.contentView.backgroundColor = UIColor.red
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at: indexPath)
cell.contentView.backgroundColor = UIColor.white
}
please bear with me as I am new to swift programming.
I have a myCollectionViewController that is a subclass of UICollectionViewController. The cells for the MyCollectionViewController are a class of MyCollectionViewCell, which is a custom UICollectionViewCell.
What I am trying to do is change the background of the MyCollectionViewCell based on the user selection AND have this selection persist when the user scrolls to other cells of the MyCollectionViewController. I have tried two ways to do this, and so far both have failed.
The first way was to write code in the didSelectItemAt method of the MyCollectionViewController:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "myCell", for: indexPath) as! MyCollectionViewCell
cell.contentView.backgroundColor = UIColor.red
}
However, this did not work and the cell colour was not changed.
The other way I tried to do this was by changing the isSelected property of the MyCollectionViewCell.
override var isSelected: Bool {
// Change what happens when the user selects a cell
didSet {
if self.isSelected {
self.contentView.backgroundColor = Colours.primary
} else {
self.contentView.backgroundColor = Colours.secondary
}
}
}
Although this worked, the selection did not persist. That is when the user scrolled to a different cell in the collectionView and then scrolled back, the selection was gone.
Any advice would be appreciated.
Don't use dequeue in didSelectItemAt as it'll return other cell than the clicked
var allInde = [IndexPath]()
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let cell = collectionView.cellForItem(at:indexPath) as! MyCollectionViewCell
cell.contentView.backgroundColor = UIColor.red
if !(allIndex.contains(indexPath)) {
allInde.append(indexPath)
}
}
and in cellForItem check whether indexpath to show is in the array and color it
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "id", for: indexPath as IndexPath) as! MyCollectionViewCell
if allIndex.contains(indexPath) {
cell.contentView.backgroundColor = Colours.primary
}
else {
cell.contentView.backgroundColor = Colours.secondary
}
}
// se here updated code
SPRAIN
I'm trying to implement this feature: in my app, if I selected a cell in UICollectionView, then the borders becomes blue, and if I select another one, the previous should be deselected and borders should become transparent. There is methods that I've written:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! ChatCell
/* Set some settings */
if globalSelected[indexPath.item] {
cell.circleView.layer.borderColor = UIColor.blue.cgColor
} else {
cell.circleView.layer.borderColor = UIColor.clear.cgColor
}
return cell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//Global variable for maintain selection
global.selectedChatPath = indexPath
globalSelected[indexPath.item] = true
collectionView.reloadData()
}
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
if indexPath != nilPath {
globalSelected[indexPath.item] = false
collectionView.reloadData()
}
}
The nilPath is just IndexPath(item: -1, section: 0), but it doesn't matter, because collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) isn't even called. My CollectionView has allowSelection = true and allowsMultipleSelection = false properties. I will be thankful for any help.
If only a single cell is supposed to be selected at the same time I recommend to put the currently selected index path into a instance variable (nil means nothing is selected)
var selectedIndexPath : IndexPath?
In cellForItemAtset the colors depending on the instance variable
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! ChatCell
/* Set some settings */
if let selected = selectedIndexPath, selected == indexPath {
cell.circleView.layer.borderColor = UIColor.blue.cgColor
} else {
cell.circleView.layer.borderColor = UIColor.clear.cgColor
}
return cell
}
In didSelectItemAt reload only the previous and new selected cells and set selectedIndexPath to the new selected index path. This is more efficient than reloading the entire collection view.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
//Global variable for maintain selection
var cellsToReload = [indexPath]
if let selected = selectedIndexPath {
cellsToReload.append(selected)
}
selectedIndexPath = indexPath
collectionView.reloadItems(at: cellsToReload)
}
didDeselectItemAt is only needed if you want to deselect a cell explicitly.
Try this
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! ChatCell
/* Set some settings */
if globalSelected[indexPath.item] {
cell.circleView.layer.borderColor = UIColor.blue.cgColor
collectionView.selectItemAtIndexPath(indexPath, animated: false, scrollPosition: .None)
}
else {
cell.circleView.layer.borderColor = UIColor.clear.cgColor
collectionView.deselectItemAtIndexPath(indexPath, animated: false)
}
return cell
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! CollectionViewCell
if selectedIndex == indexPath.item {
cell.backgroundColor = .blue
} else {
cell.backgroundColor = .clear
}
}
and in didSelectItemAt,
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedIndex = indexPath.item
collectionView.reloadData()
}
Reload your UICollectionView everytime a cell is selected and then change the border of the desired cell.
When you reload data the border for the previous cell is removed, after which you can add border to the cell that you want.
didDeselectItem won't be called until you tap the selected cell again. In order to deselect the previously selected cell when you tap another cell, you need to set the previously selected cell's setting in the global variable to false in didSelectItem like the following:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
globalSelected[global.selectedChatPath.item] = false //Set the previously selected cell's setting to false
//Global variable for maintain selection
global.selectedChatPath = indexPath
globalSelected[indexPath.item] = true
collectionView.reloadData()
}