So every time I scroll my tableView it reloads data which I find ridiculous since it makes no sense to reload data as it hasn't been changed.
So I setup my tableView as follows:
func numberOfSections(in tableView: UITableView) -> Int {
return self.numberOfElements
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 6
}
My cells are really custom and they require spacing between them. I couldn't add an extra View to my cell to fake that spacing because I have corner radius and it just ruins it. So I had to make each row = a section and set the spacing as a section height.
My cell has a dynamic height and can change it's height when I click "more" button, so the cell extends a little.
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if self.segmentedControl.selectedSegmentIndex == 0 {
if self.isCellSelectedAt[indexPath.section] {
return self.fullCellHeight
} else {
return self.shortCellHeight
}
} else {
return 148
}
}
And here's how I setup my cell:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = UITableViewCell()
if self.segmentedControl.selectedSegmentIndex == 0 {
cell = tableView.dequeueReusableCell(withIdentifier: String.className(CurrentDocCell.self)) as! CurrentDocCell
(cell as! CurrentDocCell).delegate = self
(cell as! CurrentDocCell).ID = indexPath.section
} else {
cell = tableView.dequeueReusableCell(withIdentifier: String.className(PromissoryDocCell.self)) as! PromissoryDocCell
}
return cell
}
So I have a segmentedControl by switching which I can present either one cell of a certain height or the other one which is expandable.
In my viewDidLoad I have only these settings for tableView:
self.tableView.registerCellNib(CurrentDocCell.self)
self.tableView.registerCellNib(PromissoryDocCell.self)
And to expand the cell I have this delegate method:
func showDetails(at ID: Int) {
self.tableView.beginUpdates()
self.isCellSelectedAt[ID] = !self.isCellSelectedAt[ID]
self.tableView.endUpdates()
}
I set a breakpoint at cellForRowAt tableView method and it indeed gets called every time I scroll my tableView.
Any ideas? I feel like doing another approach to make cell spacing might fix this issue.
A UITableView only loads that part of its datasource which gets currently displayed. This dramatically increases the performance of the tableview, especially if the datasource contains thousands of records.
So it is the normal behaviour to reload the needed parts of the datasource when you scroll.
Related
I have a tableview. I created it from storyboard it is a static tableview.(I am using it for profile settings).
But i have to change height of the first row of this table view dynamically and i don't want to change other cell heights. They should use their storyboard height values. How can i do this?
I tried following code:
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.row == 0 {
return 100
}
return (tableView.cellForRow(at: indexPath)?.bounds.height)!
}
But this is setting 100 for all cells.
My tableview:
Use the following override function..
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.row == 0 {
return 100
}
return UITableView.automaticDimension
}
But you have to make sure that every item in the static tableview have (top/bottom/left/right) constraints. it only works when it have all these constraints on it.
Hello,
i have created a UITableView in which it has two different cells DynamicFormCell and StaticFormCell, so the DynamicFormCell can be displayed number of times i have a data from a server telling me how many forms i need for the DynamicFormCell and the StaticFormCell is always the same and doesn't change so i am having difficulty giving different number of rows for each cell.i tried giving the two cell a tag of 0 and 1 respectively and used this code:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if(tableView.tag == 0){
return 5//return five dynamic cells
}
if(tableView.tag == 1){
return 1//return one static cell
}
}
but this doesn't work and i also tried removing all the tags and if statements in the above code and just doing this return 5 this just gave me one DynamicFormCell and five StaticFormCells.
i also gave different classes for the two cells so i can assign them separately:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if(indexPath.row == 0){
//firstRow make dynamic
let cell = tableView.dequeueReusableCell(withIdentifier: "DynamicFormsCell") as! DynamicFormsCell
return cell
}else{
//static form data
let cell = tableView.dequeueReusableCell(withIdentifier: "StaticFormsCell") as! StaticFormsCell
return cell
}
}
so my question is, is it possible to do this using table views and how can i do it? if not what other options do i have?
Yes it is possible to have multiple types of cell in single tableview. It has nothing to do with function
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
You should return there cells as,
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return (count of dynamic cells + count of static cells)
}
I assume, you only have to display static cells in the bottom. So if there are total 5 cells then 4 cells are dynamic and 5th cell would be static.
So code for, cellForRowAt indexPath: will be,
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if(indexPath.row < (count for dynamic cells)){
//first 4 Rows make dynamic
let cell = tableView.dequeueReusableCell(withIdentifier: "DynamicFormsCell") as! DynamicFormsCell
return cell
}else{
//last row static form data
let cell = tableView.dequeueReusableCell(withIdentifier: "StaticFormsCell") as! StaticFormsCell
return cell
}
}
What you're doing right now is checking if the TableView's tag is 0 or 1. Which is not you want to do, since you're using only one TableView.
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return (amount of DynamicCellsYouWant + amount of StaticCellsYouWant)
}
The second part of your code only works when you want the first cell to be a DynamicFormsCell and the rest to be a StaticFormsCell.
I have a table view cell. I make an app for a tenant in the apartment to report the defect of the room facility. if the defect has been repaired (status: Complete), data from server will give defect.status == 2 (if defect.status == 1, still on process to be repaired), and it will show YES and NO Button like the picture above.
I want if it still on the repairment process, the view that contains "Are You satisfied" label and Yes No Button will not appear. The expected result should be like the picture below
here is the code I use to remove that satisfied or not view
extension RequestDefectVC : UITableViewDataSource {
//MARK: Table View Delegate & Datasource
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return listDefects.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.removeFromSuperview()
}
}
return cell
}
}
but unfortunately, if that wantToRemoveView.removeFromSuperview() is triggered, it will remove all the view in all cell, even though the status is completed like picture below
I want that satisfied or not view appears if the status is complete, otherwise, it will be removed. how to do that ?
For your costumed cells are reused, removing views will cause uncertain effects. You don't actually need the specific view to be removed, only if it stays invisible.
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = true
}
} else {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = false
}
}
Create a height constraint for that view and hook it as IBOutlet and control it's constant according to that in cellForRowAt
self.askViewH.constant = show ? 50 : 0
cell.layoutIfNeeded()
return cell
I expect you using automatic tableView cells
#Alexa289 One suggestion is that you can take heightConstraints of UIView. then create IBOutlet of your height constraints and make its constant 0 when you want to hide otherwise assign value to your static height.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisficationHeightConstraints.constant = 50
} else {
cell.viewSatisficationHeightConstraints.constant = 0
}
return cell
}
Second suggestion is that you can take label and button in view and embed stackview to your view(view contain label and button)
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisfication.isHidden = false
} else {
cell.viewSatisfication.isHidden = true
}
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
override func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
you can read about UIStackView which makes hiding things easier. If you are not using stackview and hiding things the UI will not good as the space used by the hidden view will be still there. So better to use stackView when need to hide or show some view.
UIStackView : https://developer.apple.com/documentation/uikit/uistackview
Loading all the date from the firebase to the tableview at a time but i wanted to load 10 items at a time when i scroll to bottom again 10 items should load to the tableview, below is my code
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let item = items[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "inciCell") as!
IncidentCell
cell.delegate = self
cell.setupCell(with: item, indexPath)
return cell
}
}
In the delegate method cellForRowAtIndexPath you may check something like indexPath.row == items.count - 1.
if it's true, then you get 10 items from your DB and append it to your `items.
then do tableView.reloadData() to update the table view with 10 new items.
You may also make some nice spinner in the bottom (tableFooterView) of the table view. But it could be the next step.
Hope it helps.
Requirement :
I have a list of UITableviewCell loaded from a nib that I'm presenting on UITableview. The first time I open the UIViewController all cells are shown correctly and work as expected.
Issue :
If I navigate back to the parent and then open the UIViewController again the UITableviewCell are 'invisible'. I say invisible because with a breakpoint in cellForRowAt I can see that the table view does load all cells and the cells are valid.
Code :
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 13
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = (project?.sliderData.sliders[indexPath.row].view)! as UITableViewCell
print(cell.contentView.subviews.count)
if let left = cell.viewWithTag(2) as? UILabel {
left.text = "left"
}
if let middle = cell.viewWithTag(3) as? UILabel {
middle.text = "middle"
}
if let right = cell.viewWithTag(4) as? UILabel {
right.text = "right"
}
return cell
}
Screen Shot Image
Expected observation :
I was thinking that maybe the subviews of the cells get released because I don't have any bindings to them in IB. To test this I'm printing the count of subviews and writing some text to the subview labels. And everything seems to go fine, the cells are loaded and the labels are there but the cells just don't show up.
But then, if I scroll the TableView up and down a little to get some cells updated those cells do appear at the top and bottom of the view as shown in the pic.
You need to call dequeueReusableCell(withIdentifier: "cell") inside your code then will show your table cell. It will reuse cell for your all numbers of row data content.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! UITableViewCell
return cell
}
More Details : How to create uitableview with multiple sections in iOS Swift.
Did not find reason why the tableView behaves the way it does so I solved the issue by dequeueing default cells. The views provided by the slider objects are added as subviews to the dequeued cells. Now the subviews can of course be any UIViews.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCell(withIdentifier: "sliderCell")
if cell == nil {
cell = UITableViewCell.init(style: .default, reuseIdentifier: "sliderCell")
}
cell?.addSubview((project?.sliderData.sliders[indexPath.row].view)!)
return cell!
}