I am trying to make a table view with multiple sections, but for some (presumably dumb) reason only the first section is visible on my table view.
var labels = ["label1", "label2"]
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 2
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
var sectionHeader = ""
if section == 0 {
sectionHeader = "first section header"
} else if section == 1 {
sectionHeader = "second section header"
}
return sectionHeader
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! UITableViewCell
if indexPath.section == 0 {
cell.textLabel!.text = labels[0]
} else if indexPath.section == 1 {
cell.textLabel!.text = labels[1]
}
return cell
}
The header for the first section appears along with a cell with label text "label1" but the second section is no where to be found.
Is there some sort of setting I am not setting? What am I doing wrong here.
Your code looks good , Few things you can check
1> Tableview's frame is not large enough to fit 2 section and it's not scroll-able also.
2> heightForRow delegate method or viewForHeader or heightforHeader returns 0 or nil
3> Your constraints are breaking at runtime and that's why tableview is not visible properly (you need to check console at runtime)
You can start visual debugger of XCode at runtime and see if your table view is not hidden by some other component etc... (Debug View Hierarchy)
Related
I'm implementing collapsable section headers in a UITableViewController.
Here's how I determine how many rows to show per section:
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
return self.sections[section].isCollapsed ? 0 : self.sections[section].items.count
}
There is a struct that holds the section info with a bool for 'isCollapsed'.
Here's how I'm toggling their states:
private func getSectionsNeedReload(_ section: Int) -> [Int]
{
var sectionsToReload: [Int] = [section]
let toggleSelectedSection = !sections[section].isCollapsed
// Toggle collapse
self.sections[section].isCollapsed = toggleSelectedSection
if self.previouslyOpenSection != -1 && section != self.previouslyOpenSection
{
self.sections[self.previouslyOpenSection].isCollapsed = !self.sections[self.previouslyOpenSection].isCollapsed
sectionsToReload.append(self.previouslyOpenSection)
self.previouslyOpenSection = section
}
else if section == self.previouslyOpenSection
{
self.previouslyOpenSection = -1
}
else
{
self.previouslyOpenSection = section
}
return sectionsToReload
}
internal func toggleSection(_ header: CollapsibleTableViewHeader, section: Int)
{
let sectionsNeedReload = getSectionsNeedReload(section)
self.tableView.beginUpdates()
self.tableView.reloadSections(IndexSet(sectionsNeedReload), with: .automatic)
self.tableView.endUpdates()
}
Everything is working and animating nicely, however in the console when collapsing an expanded section, I get this [Assert]:
[Assert] Unable to determine new global row index for preReloadFirstVisibleRow (0)
This happens, regardless of whether it's the same opened Section, closing (collapsing), or if I'm opening another section and 'auto-closing' the previously open section.
I'm not doing anything with the data; that's persistent.
Could anyone help explain what's missing? Thanks
In order for a tableView to know where it is while it's reloading rows etc, it tries to find an "anchor row" which it uses as a reference. This is called a preReloadFirstVisibleRow. Since this tableView might not have any visible rows at some point because of all the sections being collapsed, the tableView will get confused as it can't find an anchor. It will then reset to the top.
Solution:
Add a 0 height row to every group which is collapsed. That way, even if a section is collapsed, there's a still a row present (albeit of 0px height). The tableView then always has something to hook onto as a reference. You will see this in effect by the addition of a row in numberOfRowsInSection if the rowcount is 0 and handling any further indexPath.row calls by making sure to return the phatom cell value before indexPath.row is needed if the datasource.visibleRows is 0.
It's easier to demo in code:
func numberOfSections(in tableView: UITableView) -> Int {
return datasource.count
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return datasource[section].visibleRows.count == 0 ? 1 : datasource[section].visibleRows.count
}
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
datasource[section].section = section
return datasource[section]
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if datasource[indexPath.section].visibleRows.count == 0 { return 0 }
return datasource[indexPath.section].visibleRows[indexPath.row].bounds.height
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if datasource[indexPath.section].visibleRows.count == 0 { return UITableViewCell() }
// I've left this stuff here to show the real contents of a cell - note how
// the phantom cell was returned before this point.
let section = datasource[indexPath.section]
let cell = TTSContentCell(withView: section.visibleRows[indexPath.row])
cell.accessibilityLabel = "cell_\(indexPath.section)_\(indexPath.row)"
cell.accessibilityIdentifier = "cell_\(indexPath.section)_\(indexPath.row)"
cell.showsReorderControl = true
return cell
}
I have implemented a tableview (4 sectional) in IOS. Problem is that
I have just added a section header in first section.Other sections don't have a header.First section does not have row (number of rows is 0).other sections have multiple rows.When I scroll , first section's header is not sticky.it is scrolling and out of screen.My table view style is plain.How can I want to make first section's header is always sticky.Code is below.Unfortunatelly tableview is so complicated and I don't want to make it only one section so that I have implemented it multi sectional.
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
if section == 0 {
return tabHeaderView.contentView
}
else {
return UIView()
}
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
if section == 0 {
return UITableView.automaticDimension
}
else {
return 0 //just first section have a header (tabview)
}
}
func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return CGFloat.leastNormalMagnitude
}
func numberOfSections(in tableView: UITableView) -> Int {
if dataReady {
totalSectionCount = getSectionCount()
return totalSectionCount
}
else {
return 1 //permanent because of tabview
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
if !dataReady || ApplicationContext.instance.userAuthenticationStatus.value == .semiSecure{
return 1//for shimmer cell and semisecure view
}
else {
return getNumberOfRows(sectionNumber: section)
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if ApplicationContext.instance.userAuthenticationStatus.value == .semiSecure {
semisecureViewCell = EarningsSemisecureViewCell()
setSemisecureViewTextInfo(cell: semisecureViewCell)
semisecureViewCell.delegate = self
semisecureViewCell.layoutIfNeeded()
return semisecureViewCell
}
else if !dataReady {
return getShimmerCell()
}
else {
if indexPath.row == 0 && !(selectedTabIndex == .BRANDPOINT && indexPath.section == 1){//marka puan listesinde header cell olmayacak
return getSectionHeaderViewCell(tableView: tableView,sectionNumber: indexPath.section)
}
else {
let cell = getTableViewCell(tableView: tableView, indexPath: indexPath)
cell.layoutIfNeeded()
return cell
}
}
}
Each section header will stick to the top until that section has some rows to display. Once you scroll all the rows for the section up. section header will be replaced by the next section header.
Here you can use one of the two solutions.
Instead of table view section header. Put your view on top of UITableView.
You can use only one section and combine all the rows in it.
From how you are describing your setup, I tend to believe that what you are looking for is the tableHeaderView of the tableView, not the section header.
See either this question, or official documentation for more info.
If that does not meet your requirements, you might wanna consider a custom view on top of the tableView, as is described here.
If the first section must always be sticky when any section is displaying, I will consider to put a custom view on top of tableView. Use autoLayout or UIStackView to let it work as a table header view.
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.
I am new to iOS Development and I just implemented a simple expandable sections UITableView. I am not able to understand why some rows disappear and sometimes change position when the row heights are recalculated on tapping the section header. I went through all the already answered questions on this topic and have not been able to find the right solution.
Following is a scenario:
Launch the app:
Tap on the section header:
Section expands
All other headers disappear
Tap again
Section collapses
The headers continue to be blank
Scrolled to the bottom and back to the top
The positions of headers changed
Scrolled to the bottom and back to the top again
The positions of headers changed again with some cells still blank
Things I have already tried:
Wrapping reloadRowsAtIndexPaths in updates block (beginUpdates() and endUpdates())
Using reloadRowsAtIndexPaths with animation set to .none
Removing reloadRowsAtIndexPaths at all while keeping the updates block
Using reloadData() instead which actually works but I lose animation
Code:
Here is the link to the project repository.
You're using cells for the header. You shouldn't do that, you need a regular UIView there, or at least a cell that's not being dequeued like that. There's a few warnings when you run it that give that away. Usually just make a standalone xib with the view and then have a static method like this in your header class. Make sure you tie your outlets to the view itself, and NOT the owner:
static func view() -> HeaderView {
return Bundle.main.loadNibNamed("HeaderView", owner: nil, options: nil)![0] as! HeaderView
}
You're reloading the cells in the section that grows, but when you change the section that's grown you'd need to at least reload the former section for it to take the changes to it's cell's height. You can reload the section by index instead of individual rows in both cases
Ok as you ask, I am changing my answer according to you.
import UIKit
class MyTableViewController: UITableViewController {
let rows = 2
var categories = [Int](repeating: 0, count: 10)
struct Constants {
static let noSelectedSection = -1
}
var selectedSection: Int = Constants.noSelectedSection
func selectedChanged(to selected: Int?) {
let oldIndex = selectedSection;
if let s = selected {
if selectedSection != s {
selectedSection = s
} else {
selectedSection = Constants.noSelectedSection
}
tableView.beginUpdates()
if(oldIndex != -1){
tableView.reloadSections([oldIndex,s], with: .automatic)
}else{
tableView.reloadSections([s], with: .automatic)
}
tableView.endUpdates()
}
}
override func numberOfSections(in tableView: UITableView) -> Int {
return categories.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("reloading section \(section)")
return (selectedSection == section) ? rows : 0;//rows
}
override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return tableView.rowHeight
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return tableView.rowHeight
}
override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let cell = tableView.dequeueReusableCell(withIdentifier: "Header")
if let categoryCell = cell as? MyTableViewCell {
categoryCell.category = section + 1
let recognizer = UITapGestureRecognizer(target: self, action: #selector(handleTapGesture))
recognizer.numberOfTapsRequired = 1
recognizer.numberOfTouchesRequired = 1
categoryCell.contentView.tag = section;
categoryCell.contentView.addGestureRecognizer(recognizer)
}
return cell?.contentView
}
func handleTapGesture(recognizer: UITapGestureRecognizer) {
if let sindex = recognizer.view?.tag {
selectedChanged(to: sindex)
}
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Body", for: indexPath)
if let label = cell.viewWithTag(1) as? UILabel {
label.text = "Body \(indexPath.section + 1) - \(indexPath.row + 1)"
}
return cell
}
}
As you can see now I am just reloading a particular section instead of reloading the whole table.
also, I have removed gesture recognizer from the cell & put this into the main controller.
I'm trying to return two seperate .counts in my UITableView. I kind of know the logic behind it but not using the syntax right. How can I do this? What I want it to do is fill my tableview up with the both .counts. I would also like to put in a label on top of the first section and second section. Anything would help!
Here is what I have so far but I'm only getting the first section of cells. Why isnt it displaying both .counts?
func tableView(tableView: UITableView, numberOfSectionsInTableView: Int) -> Int{
return 2;
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if (section == 0){
return featSubNames.count
}
else{
return subCatNames.count
}
}
func tableView(tableView: UITableView!, viewForHeaderInSection section: Int) -> UIView! {
if (section == 0){
????
}
if (section == 1){
????
}
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as UITableViewCell
// Configure the cell
switch (indexPath.section) {
case 0:
cell.textLabel?.text = featSubName[indexPath.row]
cell.textLabel?.textColor = UIColor.whiteColor()
case 1:
cell.textLabel?.text = subCatNames[indexPath.row]
cell.textLabel?.textColor = UIColor.whiteColor()
default:
cell.textLabel?.text = "Other"
}
return cell
}
Your code seems to be right. To get the UIViews on the header of each section, you can return any object that inherits from a UIView(this doesn't mean that would be nice to). So, you can return a small container with a UIImageView and a UILabel, if you want this for example.
Your code for the viewHeader would be something like this:
func tableView(tableView: UITableView!, viewForHeaderInSection section: Int) -> UIView! {
// instantiate the view to be returned and placed correctly
let commonLabel = UILabel(frame: CGRectMake(0, 0, tableWidth, 30))
commonLabel.textColor = .blackColor()
commonLabel.textAlignment = .Center
// ... other settings in the properties
if section == 0 {
commonLabel.text = "section1"
// other settings for the first section
}
if section == 1 {
commonLabel.text = "section2"
// other settings ...
}
return commonLabel
}
Notes:
Be sure to set the container view's frame,for sectionHeaders the top view in the hierarchy don't accept auto layout.
Implementing the viewForHeaderInSection method is more accessible to custom UI's, you can use the TitleForHeaderInSection if you wish, but it's limited for more complex stuffs.
EDIT:
If you're using storyboards, you still can use this code, although it's not so elegant in terms of apps that use IB for the UI. For this, you might take a look at this link: How to Implement Custom Table View Section Headers and Footers with Storyboard
. This implements only the view using storyboards, but the delegate part must to be wrote.