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How to handle drag and drop between two collection-view cell. we also have cell reorder functionality(implemented).
What exactly we need is: drag cell's subview (UILabel) and drop it to another cell
You can try the following:
Add long press gesture to cell label.
On tap begin you hide the source label and create a snapshot of the label.
then drag it to the destination cell, get the index path from the location of the touchpoints.
On ending the gesture, add the label text to the destination cell label, and remove the snapshot.
I think this will work. I had not tried this before, but I think this will work.
Step 1 : First You need to set drag and drop delegate like as below
collectionView1.dragDelegate = self
collectionView2.dropDelegate = self
Step 2 : You need to add which item to drag in itemsForBeginning delegate method
func collectionView(_ collectionView: UICollectionView, itemsForBeginning session: UIDragSession, at indexPath: IndexPath) -> [UIDragItem]
{
let item = imageArray[indexPath.row]
let itemProvider = NSItemProvider(object: item as NSString) //Here For your use case you can add label for drag
let dragItem = UIDragItem(itemProvider: itemProvider)
dragItem.localObject = item
return [dragItem]
}
Step 3 : You need to add performDropWith delegate method to drop item for collectionView2
func collectionView(_ collectionView: UICollectionView, performDropWith coordinator: UICollectionViewDropCoordinator)
{
let destinationIndexPath : IndexPath
if let indexPath = coordinator.destinationIndexPath
{
destinationIndexPath = indexPath
}
else
{
let row = collectionView.numberOfItems(inSection: 0)
destinationIndexPath = IndexPath(item: row - 1, section: 0)
}
if coordinator.proposal.operation == .copy
{
//Here you can add your copy code
}
}
Related
In Swift.
When reselecting the first item it works very well (it is deselected) but I have the problem that
when using "collection.allowsMultipleSelection = true" when selecting the second or third item it paints everything for me (which I don't want). Any solution to be able to deselect the previous item and when I select the new item that changes the deselected item (previous)? In swift.
It sounds like your goal is:
allow only a single cell to be selected at a time
also allow tapping a selected cell to de-select it
If so, you can do it a couple different ways.
One - set the collection view .allowsMultipleSelection = false and implement shouldSelectItemAt:
func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
// get array of already selected index paths
if let a = collectionView.indexPathsForSelectedItems {
// if that array contains indexPath, that means
// it is already selected, so
if a.contains(indexPath) {
// deselect it
collectionView.deselectItem(at: indexPath, animated: false)
return false
}
}
// no indexPaths (cells) were selected, so return true
return true
}
Two - set .allowsMultipleSelection = true and implement didSelectItemAt:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
// get array of already selected index paths
if let a = collectionView.indexPathsForSelectedItems {
// for each path in selected index paths
a.forEach { pth in
// if it is NOT equal to the tapped cell
if pth != indexPath {
// deselect it
collectionView.deselectItem(at: pth, animated: false)
}
}
}
}
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i have a UITableViewController configured with a static table made up of 5 custom cells (this is meant to be a form).
cell 0 captures a date
cell 1 is a UICollectionView filled with icons representing activities. depending on which activity is selected, one of many custom UITableViewCell are loaded on the fly in cell 2 .
cell 2 can be simple (just a slider), a textfield or more complex (a UITableView)
cell 3 has a textfield to capture a description.
cell 4 is for additional notes
so far everything is working as expected. I select an activity in cell 1, the matching XIB is loaded in cell 2, data is captured, comment added etc and form is saved. Where i am challenged is in the case where based on the the input in cell 2, i would like to update cell 3 automatically. i got it working but i feel it isn't elegant or clean so would appreciate others input. in
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// main table cells pseudo code
switch indexPath.row {
case 0:
<#code#>
case 1:
// dequeue collectionviewcell
case 2:
// dequeue the relevant uitableviewcell based on selected cell in the uicollectionview
switch selectedIndexPath.row {
case 2:
<#code#>
default:
<#code#>
}
case 3:
// handle the description field
default:
<#code#>
}
a specific activity will load "eventFlushMedTableViewCell" which is meant to display a list of meds in a uitableview. based on which meds I select, i would like to take the name of the meds and put them in cell 3.
case 2:
let cell = tableView.dequeueReusableCell(withIdentifier: "eventFlushMedTableViewCell", for: indexPath) as! eventFlushMedTableViewCell
// fill the meds table with the list of Rx meds
cell.medsArray = medListArray.filter { $0.medRx == 1}.map {return $0.medName}
// return the selected values from the table
cell.returnValue = { selectedIndexPaths in
let indexList = selectedIndexPaths.map { $0.row }
self.selectedMedsName = indexList.map {cell.medsArray[$0]}
// force a reload of cell 3
let myIndexPath = IndexPath.init(row: 3, section: 0)
tableView.reloadRows(at: [myIndexPath], with: .none)
}
return cell
and cell 3 in the main table is dequeued and configured
case 3:
let cell = tableView.dequeueReusableCell(withIdentifier: "eventDescriptionCell", for: indexPath) as! eventDescriptionCell
if !selectedMedsName.isEmpty {
cell.eventDescriptionTextField.text = selectedMedsName.joined(separator: ", ")
}
something tells me the closure around (cell.returnValue {...}) in case 2:, even though it is working, isn't the right way of doing this... any advice ?
thanks
I think a good way of approaching this would be to create a custom delegate.
Let's name it ActivityCellDelegate. You can create it like this:
protocol ActivityCellDelegate: class {
func activitySelected(_ activity: Activity)
}
We use 'class' so we can make the delegate 'weak' reference. Otherwise XCode will cause trouble :).
Using an enum to represent different activities is a nice touch. You could also use a String as an identifier or an Int as an id.
enum Activity {
case activity1
case activity2
...
}
Add a delegate property to the TableViewCell:
weak var cellDelegate: ActivityCellDelegate?
Then, when dequeuing a cell, you set it's delegate to self cell.cellDelegate = self, and make the controller that has tableView as a subview conform to the delegate protocol.
extension TableViewController: ActivityCellDelegate {
func activitySelected(_ activity: Activity) {
//...in here you would probably reload the third cell in the table view. You could add an additional property in the ViewController in order to know which activity is currently selected.
}
}
In the end, when user selects a CollectionViewCell to choose an activity in collectionView:didSelectItemAtIndexPath: you should call the delegate method:
delegate?.activitySelected(.activity1)
I'm currently making a screen that has an UITableView with many sections that have the content of cells is UICollectionView. Now I'm saving the selected indexPath of the collection into an array then save to UserDefaults (because the requirement is showing all cells has selected before when reopening view controller).
But I have the issues is when I reopen view controller all items in all sections with the same selected indexPath show the same state.
I know it occurs because I just save the only indexPath of the selected item without the section of UITableview which is holding the collection view. But I don't know how to check the sections. Can someone please help me to solve this problem? Thank in advance.
I'm following this solution How do I got Multiple Selections in UICollection View using Swift 4
And here is what I do in my code:
var usrDefault = UserDefaults.standard
var encodedData: Data?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
if let act = usrDefault.data(forKey: "selected") {
let outData = NSKeyedUnarchiver.unarchiveObject(with: act)
arrSelectedIndex = outData as! [IndexPath]
}else {
arrSelectedData = []
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let optionItemCell = collectionView.dequeueReusableCell(withReuseIdentifier: "optionCell", for: indexPath) as! SDFilterCollectionCell
let title = itemFilter[indexPath.section].value[indexPath.item].option_name
if arrSelectedIndex.contains(indexPath) {
optionItemCell.filterSelectionComponent?.bind(title: title!, style: .select)
optionItemCell.backgroundColor = UIColor(hexaString: SDDSColor.color_red_50.rawValue)
optionItemCell.layer.borderColor = UIColor(hexaString: SDDSColor.color_red_300.rawValue).cgColor
}else {
optionItemCell.backgroundColor = UIColor(hexaString: SDDSColor.color_white.rawValue)
optionItemCell.layer.borderColor = UIColor(hexaString: SDDSColor.color_grey_100.rawValue).cgColor
optionItemCell.filterSelectionComponent?.bind(title: title!, style: .unselect)
}
optionItemCell.layoutSubviews()
return optionItemCell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let strData = itemFilter[indexPath.section].value[indexPath.item]
let cell = collectionView.cellForItem(at: indexPath) as? SDFilterCollectionCell
cell?.filterSelectionComponent?.bind(title: strData.option_name!, style: .select)
cell?.backgroundColor = UIColor(hexaString: SDDSColor.color_red_50.rawValue)
cell?.layer.borderColor = UIColor(hexaString: SDDSColor.color_red_300.rawValue).cgColor
if arrSelectedIndex.contains(indexPath) {
arrSelectedIndex = arrSelectedIndex.filter{($0 != indexPath)}
arrSelectedData = arrSelectedData.filter{($0 != strData)}
}else {
arrSelectedIndex.append(indexPath)
arrSelectedData.append(strData)
encodedData = NSKeyedArchiver.archivedData(withRootObject: arrSelectedIndex)
usrDefault.set(encodedData, forKey: "selected")
}
if let delegate = delegate {
if itemFilter[indexPath.section].search_key.count > 0 {
if (strData.option_id != "") {
input.add(strData.option_id!)
let output = input.componentsJoined(by: ",")
data["search_key"] = itemFilter[indexPath.section].search_key.count > 0 ? itemFilter[indexPath.section].search_key : strData.search_key;
data["option_id"] = output
}
}else {
data["search_key"] = itemFilter[indexPath.section].search_key.count > 0 ? itemFilter[indexPath.section].search_key : strData.search_key;
data["option_id"] = strData.option_id
}
delegate.filterTableCellDidSelectItem(item: data, indexPath: indexPath)
}
}
This will only work based on the assumption that both your parent table view and child collection views both are not using multiple sections with multiple rows and you only need to store one value for each to represent where an item is located in each respective view.
If I am understanding correctly, you have a collection view for each table view cell. You are storing the selection of each collection view, but you need to also know the position of the collection view in the parent table? A way to do this would be to add a property to your UICollectionView class or use the tag property and set it corresponding section it is positioned in the parent table. Then when you save the selected IndexPath, you can set the section to be that collection view's property you created(or tag in the example) so that each selected indexPath.section represents the table view section, and the indexPath.row represents the collection view's row.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//...
let collectionView = UICollectionView()
collectionView.tag = indexPath.section
//...
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
indexPath.section = collectionView.tag
let strData = itemFilter[indexPath.section].value[indexPath.item]
//...
}
Basically each selected index path you save will correspond to the following:
indexPath.section = table view section
indexPath.row = collection view row
IndexPath(row: 5, section: 9) would correlate to:
--table view cell at IndexPath(row: 0, section: 9) .
----collection view cell at IndexPath(row: 5, section: 0)
Edit: This is how you can use the saved index paths in your current code
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
//...
let tempIndexPath = IndexPath(row: indexPath.row, section: collectionView.tag)
if arrSelectedIndex.contains(tempIndexPath) {
//...
} else {
//...
}
//...
}
Your statement arrSelectedIndex.contains(indexPath) in the cellForItemAt method is not correct.
Each time a UICollectionView in a UITableView's section is loaded, this will called the cellForItemAt for ALL cells.
Here is the error :
In your GIF example the first cell is selected in the first collectionView, you will store (0, 0) in the array.
But when the second collectionView will loads its cells, it will check if the indexPath (0, 0) is contained into your array. It is the case, so the backgroundColor will be selected.
This error will be reproduced on every collectionView stored in your tableView sections.
You should probably also store the sectionIndex of your UITableView into your array of IndexPath.
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I have a UICollectionView which displays content received from the web. The number of cells can be known only at runtime. Client's requirement is that each row in the collection view must have a different color.
For example, If I have to show 12 items in my UICollectionView then suppose if first row has 3 cells then the colour of all three cells should be red.
Cells of second row should be white and so on.
Could you please help me how to achieve it?
Thanks in advance.
on cellForRowAt, if you want to intercalate colors, you can check indexPath.row and update the background color.
if indexPath.item % 2 == 0 {
<#YourCell#>.backgroundColor = .blue
} else {
<#YourCell#>.backgroundColor = .green
}
Also, if you want random colors, you can check this answer: How to make a random color with Swift
Then you just set <#YourCell#>.backgroundColor the random color
In the case that the collectionViewCell has another collectionView on each cell, and those have to match the same color for each parent collectionView row, I'd suggest you to create a custom class for the parent collectionView cell, so that every collectionView child row can consume from it and set it's own backgroundColor.
Updated answer:
I'm supposing you have initially you have these variables like:
private let cellBackgroundColors: [UIColor] = [.yellow, .green, .blue, .purple]
private let numberOfRows = 3 (or you can assign it dynamically)
Second step, implement like this:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! ToDoListCollectionCell
let index = indexPath.item / numberOfRows
if index < cellBackgroundColors.count {
cell.backgroundColor = cellBackgroundColors[index]
} else {
cell.backgroundColor = .white // Set your default color to handle this case
}
return cell
}
Happy Coding !!
I have a CollectionView issue, I have a video showing the problem detailed below. When I click one cell it moves in a weird manner.
Here is my code:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedFilter = indexPath.row
if filters[indexPath.row] != "Todo" {
filteredNews = news.filter { $0.category == filters[indexPath.row] }
} else {
filteredNews = news
}
tableView.reloadData()
collectionView.reloadData()
}
My Cell is moving, (Just the last cell, don't know why).
I think it might be related to collectionView.reloadData() But I need to do that for updating the green bar you can see on this Video when I select a Cell.
How can I make it not move? Someone had had a similar problem?
I noticed you reloaded a tableView during collectionView didSelectItemAt. If that tableView is a superView of your collectionView that will be the exact reason why you are having this abnormal behaviour.
If it were not, I can offer 3 solutions:
This library have a view controller subclass that can create the effect you want to show.
Manually create a UIView/UIImageView that is not inside the collectionView but update it's position during the collectionView's didSelectItemAt delegate method to but visually over the cell instead - this would require some calculation, but your collectionView will not need to reload.
You can attempt to only reload the two affected cells using the collectionView's reloadItem(at: IndexPath) method.
Know that when you reload a table/collection view, it will not change the current visible cell. However any content in each cell will be affected.
Finally I Solve it! I removed collectionView.reloadData() and added my code to change colors inside didSelectItemAt changing current selected item and old selected item (I created a Variable to see which one was the old selected item).
If someone interested, here is my code:
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let oldSelectedFilter = selectedFilter
if selectedFilter != indexPath.row {
let oldIndexPath = IndexPath(item: oldSelectedFilter, section: 0)
selectedFilter = indexPath.row
if filters[indexPath.row] != "Todo" {
filteredNews = news.filter { $0.category == filters[indexPath.row] }
} else {
filteredNews = news
}
if let cell = collectionView.cellForItem(at: indexPath) as? FiltersCollectionViewCell {
cell.selectedView.backgroundColor = MainColor
}
if let cell = collectionView.cellForItem(at: oldIndexPath) as? FiltersCollectionViewCell {
cell.selectedView.backgroundColor = UIColor(red:0.31, green:0.33, blue:0.35, alpha:1.0)
}
tableView.reloadData()
}
}