I have a UITableView which has multiple sections and I want each section to have a different number of rows. What I have in code right now is
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
//habitsByDay is a global array contain the number of rows for each section,
//with each index of the array corresponding to the each of the sections
return habitsByDay.removeAtIndex(0)
}
Will this method be called when each section is loaded (i.e. it should be called habitsByDay.count-many times).
The table view data source methods can be called at any time, in any order.
In particular, they should not have side effects as in your example.
If habitsByDay is an array with the number of rows for each section
then just do
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return habitsByDay[section]
}
You have to use if statements for that.
For example:
if (section == 0) { //First section
return 20; } //20 rows in first section
if (section == 1) { //Second section
return 10; } //10 rows in second section
Or in your case for example.
if (section == 0) {
return habitsByDay.count }
Related
I am playing with a table as below (I've seen multiple threads on this topic but couldn't answer my question):
func numberOfSections(in _: UITableView) -> Int {
3
}
func tableView(_: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 0 {
return 3
} else if section == 1 {
return 4
} else {
return 2
}
}
Then after clicking on a cell I want a new cell inserted into the same section at row index 0. I wrote the below:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.insertRows(at: [IndexPath(row: 0, section: indexPath.section)], with: .left)
}
I get this error:
Exception NSException * "Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (3) must be equal to the number of rows contained in that section before the update (3), plus or minus the number of rows inserted or deleted from that section (1 inserted, 0 deleted) and plus or minus the number of rows moved into or out of that section (0 moved in, 0 moved out)."
I assume I should somehow update the data source, but since in my case I return const values for rows in sections is there a way to update the the number of rows in section? (the numberOfRows in section only returns immutable value). Thank you
in my case I return const values
There you go! If you are going to modify the number of rows you need variables
For example
var sections = [3,4,2]
func numberOfSections(in _: UITableView) -> Int {
return sections.count
}
func tableView(_: UITableView, numberOfRowsInSection section: Int) -> Int {
return sections[section]
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
sections[indexPath.section] += 1
tableView.insertRows(at: [IndexPath(row: 0, section: indexPath.section)], with: .left)
}
I am trying to create a single table in Xcode and I want 3 sections in that table each with different headers.
I want to stick only the header of last section when it scrolls on top not the other sections.
Is there a way to do so please suggest me..
1- Yes, you can do that. In numberOfSections method of UITableViewDelegate, specify how many sections you want. And in viewForHeaderInSection method of UITableviewDelegate, provide a custom view for each section.
func numberOfSections(in tableView: UITableView) -> Int {
return 3
}
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
// Make custom header view for each section
if section == 0 {
let header1 = UIView()
return header1
} else if section == 1 {
let header2 = UIView()
return header2
} else if section == 2 {
let header3 = UIView()
return header3
}
}
2- No, you can not do that. UITableView does not allow you to specify that which particular header should stick to the top and which one should not.
You can set the UITableView style to Plain. It will stick all the section header while scrolling.
I think that is not possible to stick the particular section header.
You could achieve the same behaviour by having a custom cell that would act as the header in the first two sections. And then remove the actual header for those.
For example:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if (indexPath.section == 0 || indexPath.section == 1) && indexPath.row == 0 {
return HeaderCell()
}
// return your desired cells (make sure to handle the number of
// rows properly as there is effectively 1 more than normal in
// in the first two sections now)
}
You'll also need to adjust the headers for the first two sections:
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
if section == 2 { return YourHeaderView() }
return nil
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
if section == 2 { return yourHeight }
return 0
}
Also, in the numberOfRows delegate function, you should make sure you add 1 (which will be the HeaderCell).
Basically I have a view controller with a static table view with 2 sections. The first section will have 1 row and represent a main category.
I want the second section to have a variable amount of rows depending on how many entries the user has for that category. So if the category is "Activities" and they have "Baseball, softball" as activities, I want there to be 2 rows in that section.
How do you do this? It keeps crashing when I code it.
You can try this.....
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 0 {
return 1
} else {
return YourDataSource.count
}
}
and on your cellforrowatindex
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 {
//Do your stuff for the static section
} else {
//Do your stuff for the dynamic section
}
}
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.
I have a static grouped table view that has 5 sections (all the sections have headers, no footers). I created all of this using a Storyboard. Now, how can I hide the first/top UITableViewSection (including the header). I tried making an outlet to the UITableViewSection but it tells me that it is not valid (undeclared type):
#IBOutlet var section: UITableViewSection!
I did it this way because I was planning on doing:
section.hidden = true
Can it not be done this way?
My delegates and data sources are set up 100% correctly.
Swift 5:
You can use the delegate method heightForHeaderInSection
:
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
if (section == 0) {
return 0.0
}
return UITableView.automaticDimension
}
Earlier than Swift 5: Use UITableViewAutomaticDimension instead of UITableView.automaticDimension
If it's not working with height 0.0, use height 0.1
If you want no cells in a particular section, use the delegate method:
func numberOfRowsInSection(section: Int) -> Int {
if (section == 0) {
return 0
}
else {
// return the number of rows you want
}
}
Or to a neater switch-case syntax:
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
switch section {
case 0:
return 0.0
default:
return UITableView.automaticDimension
}
}
I tested both and they are working fine.
I also wish you could just make an #IBOutlet to a section and hide it, but sadly it seems not, so...
Based on various suggestions here, I've established the following, which doesn't require any interfering with explicit size values, and preserves whatever you may have set on a storyboard/XIB already. It just makes the header nil and row count 0 for any section you want to hide (which results in a size of 0.0).
Obviously, you can configure sectionShouldBeHidden to work however you need; hiding #1 & #3 are just arbitrary examples.
Swift v5
private func sectionShouldBeHidden(_ section: Int) -> Bool {
switch section {
case 1, 3: return true
default: return false
}
}
override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
if sectionShouldBeHidden(section) {
return nil // Show nothing for the header of hidden sections
} else {
return super.tableView(tableView, titleForHeaderInSection: section) // Use the default header for other sections
}
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if sectionShouldBeHidden(section) {
return 0 // Don't show any rows for hidden sections
} else {
return super.tableView(tableView, numberOfRowsInSection: section) // Use the default number of rows for other sections
}
}
Update: Unfortunately, the above is only enough if the style of the table view is Plain. When it's Grouped, there's also additional space added between each section, which needs taking care of too.
This extra space is the section's footer, so can be handled like so:
override public func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
if sectionShouldBeHidden(section) {
return CGFloat.leastNormalMagnitude // Use the smallest possible value for hidden sections
} else {
return super.tableView(tableView, heightForFooterInSection: section) // Use the default footer height for other sections
}
}
I tried all the solutions here with no success. At the end, adding these delegate methods this one worked:
Swift 5:
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return section == 4 ? 0 : return super.tableView(tableView, numberOfRowsInSection: section)
}
override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return section == 4 ? 0.1 : super.tableView(tableView, heightForHeaderInSection: section)
}
override func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return section == 4 ? 0.1 super.tableView(tableView, heightForFooterInSection: section)
}
Note that you need to return 0.1 in height, returning 0 won't do it.
0.0 did not work for me. I had to do this in order to make it work.
override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
switch section {
case 0:
return 0.01
default:
return UITableViewAutomaticDimension
}
}
For group UITableView with static cells only this solution works:
self.tableView.sectionHeaderHeight = 0;
self.tableView.sectionFooterHeight = 0;
override func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
let count = self.tableView(tableView, numberOfRowsInSection: section)
if count == 0 {
return CGFloat(Double.leastNormalMagnitude)
}
return 44.0
}
For anyone wanting to hide sections because they are using a static grouped tableView with a dynamic number of sections, the solution below may be of help. In my case, each section with data to display needed to have a custom header. Any section that did not have data, needed to be hidden fully.
The answer above was of great help in my scenario. However, for those who don't always know which section(s) will need to be hidden here is a solution for you extending on the above.
In my scenario, I have up to 12 entries in an array that I want to show in up to 12 sections (amongst other sections in a grouped tableView). If there are less than 12 entries to display, I want to hide the unnecessary sections by giving them 0 height and 0 rows. I also wanted to hide the headerView.
To do this, I did the following:
Set up your tableView as per the excellent answer #sasquatch gave
above.
In the numberOfRowsInSection(section: Int) and tableView(_
tableView: UITableView, heightForHeaderInSection section: Int) functions, check whether the rows/height should be 0.
In my case, I was using sections 1 - 12 for my dynamic data so I used code as below:
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
//For section 0 and 13, just 1 row is ok
if section == 0 || section == 13 {
return 1
}
//For sections 1 - 12, determine if we have data to populate it, or if we should hide it
if section <= dynamicDataToDisplay.count {
return 2
}
//If it's section 1 - 12, but we don't have a corresponding data entry in dynamicDataToDisplay, then just return 0 rows
return 0
}
The code for the heightForHeader function is similar in logic:
override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
switch section {
case 0:
return 45.0
case 13:
return UITableViewAutomaticDimension
default:
if dynamicDataToDisplay.count >= section {
return 25.0
} else {
return 0.0
}
} //end switch
}
Even after setting up these functions, I found that I was still getting headers appearing for the sections I wanted to hide. I guess I thought that viewForHeaderInSection would not be called if the numberOfRows was 0 and heightOfHeader was also 0, but it was still being called.
Adding the following helped ensure that the header wasn't unnecessarily created:
override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
//set up header for dynamic data sections
if 1 ... 12 ~= section {
if tableView.numberOfRows(inSection: section) == 0 {
return nil
}
//Continue with the header set up for valid sections with rows to display data
......
}
}
This solution might help anyone who is still getting a header being created despite its height and rows being set to 0.