I am trying to write a function that scrolls to the bottom cell of a given section in my tableView, I'm calling this function after my tableView.reloadData() function but it is not scrolling, any ideas why?
func scrollToBottom(section: Int){
DispatchQueue.main.async {
let indexPath = IndexPath(row: self.session[section].count - 1, section: section)
self.tableView.scrollToRow(at: indexPath, at: .bottom, animated: true)
}
}
You don't need put code in DispatchQueue.main because it already run on main thread.
Try this
func scrollToBottom(section: Int){
let indexPath = IndexPath(row: self.session[section].count - 1, section: section)
self.tableView.scrollToRow(at: indexPath, at: .top, animated: true)
}
Trying to call a TableView row to be selected programatically.
All my delegates are set properly, and the UITableView is linked in IB. All other UITableView methods work properly, and are located in either the main ViewController or its extension. When the following is called I get Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value.
func selectTableViewRowProgrammatically () {
let indexPath = IndexPath(row: someVariable, section: 0)
tableView.selectRow(at: indexPath, animated: false, scrollPosition: UITableView.ScrollPosition.none)
tableView.delegate?.tableView!(self.tableView, didSelectRowAt: indexPath)
tableView.reloadData()
}
Error shows on self.tableView.selectRow(at: indexPath, animated: false, scrollPosition: UITableView.ScrollPosition.none)
Thanks!
can you try Following code
let indexPath = IndexPath(row: someVariable, section: 0)
UIView.animate(withDuration: 0.1, animations: {
tableView.scrollToRow(at: indexPath, at: .top, animated: false)
}) { (true) in
tableView.delegate?.tableView!(self.tableView, didSelectRowAt: indexPath)
}
I have a horizontal collectionview that adds a new cell every time I tap the button. I am attempting to scroll the collectionview to the next cell once the cells are no longer visible each time I tap the button.
The code I have now is not working properly
Code:
#IBAction func random(_ sender: Any) {
resultsCollection.reloadData()
let collectionBounds = resultsCollection.bounds
let contentOffset = CGFloat(floor(resultsCollection.contentOffset.x - collectionBounds.size.width))
self.moveToFrame(contentOffset: contentOffset)
}
func moveToFrame(contentOffset : CGFloat) {
let frame: CGRect = CGRect(x : contentOffset ,y : resultsCollection.contentOffset.y ,width : resultsCollection.frame.width,height : resultsCollection.frame.height)
resultsCollection.scrollRectToVisible(frame, animated: true)
}
How can I fix this so that it scrolls correctly when I tap the button?
After reload your data, call this lines.
let lastItem = resultsCollection(resultsCollection, numberOfItemsInSection: 0) - 1
let indexPath = IndexPath(row: lastItem, section: 0)
resultsCollection.scrollToItem(at: indexPath, at: .centeredHorizontally, animated: true)
Use the following code to achieve your needs. For animation, you just need to pass value true/false in animated of scrollToRow function.
Hope this will help you!
To scroll top without animation
func scrollToTopWithoutAnimation() {
DispatchQueue.main.async {
if self.dataArray.count > 0 {
let indexPath = IndexPath(row: 0, section: 0)
collectionView.scrollToItem(at: indexPath, at: .top, animated: false)
}
}
}
To scroll top with animation
func scrollToTopWithAnimation() {
DispatchQueue.main.async {
if self.dataArray.count > 0 {
let indexPath = IndexPath(row: 0, section: 0)
collectionView.scrollToItem(at: indexPath, at: .top, animated: true)
}
}
}
Set IndexPath row as per your needs
I am creating a chat interface.
User's message is put in a new UITable view cell.
And when update the table view, I use the following code.
extension UITableView {
func scrollToBottom() {
let rows = self.numberOfRows(inSection: 0)
if rows > 0 {
let indexPath = IndexPath(row: rows - 1, section: 0)
self.scrollToRow(at: indexPath, at: .bottom, animated: true)
}
}
}
Actually this works a little better, but there is something strange.
When I turn off the app and turn it on again, or after exiting the screen and entering again, the following issues arise.
The issue is that when I add a new cell, it goes up to the first cell in the table view and back down to the last cell.
See the issue(https://vimeo.com/266821436)
As the number of cells increases, the scrolling becomes too fast and too messy.
I just want to keep updating the last cell that is newly registered.
What should I do?
Please use DispatchQueue to Scroll because of the method you are fire is executed with tableView load data so we need to give time to scroll.
extension UITableView {
func scrollToBottom() {
let rows = self.numberOfRows(inSection: 0)
if rows > 0 {
DispatchQueue.main.async {
let indexPath = IndexPath(row: rows - 1, section: 0)
self.scrollToRow(at: indexPath, at: .bottom, animated: true)
}
}
}
}
or
func scrollToBottom(){
DispatchQueue.main.async {
let indexPath = IndexPath(row: self.array.count-1, section: 0)
self.tableView.scrollToRow(at: indexPath, at: .bottom, animated: true)
}
}
self.scrollToRow(at: indexPath.last ...)
I need to select a row in a UITableView programmatically using Swift 1.2.
This is the simple code:
var index = NSIndexPath(forRow: 0, inSection: 0)
self.tableView.selectRowAtIndexPath(index, animated: true, scrollPosition: UITableViewScrollPosition.Middle)
self.tableView(self.tableView, didSelectRowAtIndexPath: index)
The above gives me the following error:
Cannot invoke 'selectRowAtIndexPath' with an argument list of type '(NSIndexPath!, animated: Bool, scrollPosition: UITableViewScrollPosition)'
What is wrong with my Swift 1.2 code?
My UItableView has been created in IB in the UIViewController that I am trying to call the code above.
When I put the code in a UITableViewController the compiler does not give any errors.
Do I need to embed a UITableViewController in a container or is there another way?
Swift 3 to Swift 5 Solution
Selecting a Row
let indexPath = IndexPath(row: 0, section: 0)
myTableView.selectRow(at: indexPath, animated: true, scrollPosition: .bottom)
myTableView.delegate?.tableView!(myTableView, didSelectRowAt: indexPath)
DeSelecting a Row
let deselectIndexPath = IndexPath(row: 7, section: 0)
myTableView.deselectRow(at: deselectIndexPath, animated: true)
myTableView.delegate?.tableView!(myTableView, didDeselectRowAt: indexPath)
The statement
self.tableView.selectRowAtIndexPath(index, animated: true, scrollPosition: UITableViewScrollPosition.Middle)
assumes that tableView is a property of the view controller, connected
to a table view in the Storyboard. A UITableViewController, for example, already has this
property.
In your case, the view controller is a not a table view controller
but a subclass of a UIViewController. It also has an outlet that is
connected to the table view, but it is not called
tableView but menuTable. Then of course you have to call
self.menuTable.selectRowAtIndexPath(index, animated: true, scrollPosition: UITableViewScrollPosition.Middle)
to select a row of that table view.
The strange error messages are caused by the fact that
self.tableView can also be understood by the compiler as a
"curried function" (compare http://oleb.net/blog/2014/07/swift-instance-methods-curried-functions/).
Use below code,after loading your table view with data:
let rowToSelect:NSIndexPath = NSIndexPath(forRow: 0, inSection: 0); //slecting 0th row with 0th section
self.tableView.selectRowAtIndexPath(rowToSelect, animated: true, scrollPosition: UITableViewScrollPosition.None);
now,you have to manually call didSelectRowAtIndexPath: delegate method using below code:
self.tableView(self.tableView, didSelectRowAtIndexPath: rowToSelect); //Manually trigger the row to select
Thanks.
Swift 3.x
if you want to do it at the 'cell-creation', you can do it like this
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = TableViewCell()
let item = items[indexPath.row]
cell.textLabel?.text = item.title
if (item.checked) {
tableView.selectRow(at: indexPath, animated: false, scrollPosition: .none)
}
return cell
}
Using Swift 2.x, as described by Pankaj purohit answers the correct method is:
func tapRowAtIndex(index:Int) {
let rowToSelect:NSIndexPath = NSIndexPath(forRow: index, inSection: 0)
self.tableView.selectRowAtIndexPath(rowToSelect, animated: true, scrollPosition: UITableViewScrollPosition.None)
self.tableView(self.tableView, didSelectRowAtIndexPath: rowToSelect)
}
Keep in mind that if you call this method from an external class for example, you dont know when tableView has finished its loading, so what's the possibilities?, how to workaround this problem? :
Step one: create a class boolean var
var automatingTap: Bool = false
Step two: check when the table finish its loading and launch an "end operations" method:
func tableView(tableView: UITableView, didEndDisplayingCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath)
{
let lastRowIndex = tableView.numberOfRowsInSection(0)
if indexPath.row == lastRowIndex - 1 {
endOperations()
}
}
func endOperations()
{
print("finished loading")
if automatingTap {
tapRowAtIndex(0)
automatingTap = false
}
}
Step three: call my tableView class from another class
for example:
override func prepareForSegue(segue: UIStoryboardSegue?, sender: AnyObject?) {
if segue!.identifier == "DetailsTableView" {
let viewController:ViewController = segue!.destinationViewController as ViewController
viewController.automatingTap = true
}
}
Reusable function with validation of table size
Swift 4 and 5
This reusable function works and validate the size of table.
func selectRow(tableView: UITableView, position: Int) {
let sizeTable = tableView.numberOfRows(inSection: 0)
guard position >= 0 && position < sizeTable else { return }
let indexPath = IndexPath(row: position, section: 0)
tableView.selectRow(at: indexPath, animated: true, scrollPosition: .middle)
}
you can use it in this way
selectRow(tableView: myTableView, position: pos)
or you can implement this extension:
extension UITableView {
func selectRow(row: Int, section: Int = 0) {
let sizeTable = self.numberOfRows(inSection: section)
guard row >= 0 && row < sizeTable else { return }
let indexPath = IndexPath(row: row, section: section)
self.selectRow(at: indexPath, animated: true, scrollPosition: .middle)
}
}
and you can use it in this way:
mytableView.selectRow(row: pos, section: 0)
or
mytableView.selectRow(row: pos)
Swift 4.2:
Select one or more Rows
let ndx:IndexSet = [1]
// or: let ndx:IndexSet = [1, 2, 3]; // etc
tableview?.selectRowIndexes(ndx, byExtendingSelection: false);
Deselect a Single Row
tableview?.deselectRow(current)
Note that if you have (func tableViewSelectionDidChange(...)) implemented, that will be triggered by the above.
Also see Charlton Provatas' answer at https://stackoverflow.com/a/48696458/352920 for an extension to NSTableView, that provides a simple
tableview?.selectRow(at:)