I'm working on a calendar created with a UICollectionView.
The UICollectionView is located inside a UITableViewCell
The UITableViewCell in the heightForRowAt method return UITableView.automaticDimension
The UICollectionView used to create the calendar updates its height based on how many days are shown, for example the month of November has its first day which falls on Sunday so to place the day under the label "Sunday" the collectionView must necessarily add a whole line.
Normally each month has 5 rows (week) but when the first day of the month happens on Sunday the collectionview returns 6
Now as I said I was able to update the height of the UICollectionView based on how many rows it returns but I cannot dynamically change the height of the TableViewCell that contains the collectionView
How can I resize the tableViewCell based on the height of the CollectionView within it?
EDIT
my cell
I have set UITableView.automaticDimension for the height of the cell that contains the CalendarView
In the class CalendarView: UIView I created a variable CGFloat calendarH to set the default height of the collectionView
CollectionView implementation
I have added an observer which tracks the height of the collctionView when it changes
I am currently able to change the height of the collectionView but its superview (bookingCalendarView) and the tableView cell continue to remain with a fixed height and do not adapt to the collectionView
You need to create an #IBOutlet for your collection view's height constraint.
When you set a row's calendar / month data, determine whether you need 5 or 6 rows.
If it's 6, set the .constant on the height constraint to 750
If it's 5, set the .constant on the height constraint to 675
Edit
First, I'm going to suggest you forget about using a "self-sizing" collection view. UICollectionView is designed to lay out cells based on the size of the collection view, providing automatic scrolling when there are too many cells.
Trying to "self-size" it may work in one instance, but fail in another. The reason it fails in this case is because your table view lays out the cell and calculates its height before the collection view is populated, and thus before it can "self-size."
Instead, since you know your cell Height is 75, you can calculate how many rows your calendar will need and either set the .constant on a height constraint for your collection view, or (since you're already using heightForRowAt) calculate the row height there.
Look at this code:
let dateComponents = DateComponents(year: year, month: month)
// startDate will be the first date of the month (Jan 1, Feb 1, Mar 1, etc...)
guard let startDate = calendar.date(from: dateComponents) else {
fatalError("Something is wrong with the date!")
}
// get the range of days in the month
guard let range = calendar.range(of: .day, in: .month, for: startDate) else {
fatalError("Something is wrong with the date!")
}
// get number of days in the month
let numberOfDaysInMonth = range.count
// get the day of the week for the first date in the month
// this returns 1-based numbering
// Nov 1, 2020 was a Sunday, so this would return 1
let startDayOfWeek = Calendar.current.component(.weekday, from: startDate)
// add the "leading days to the start date"
// so, if startDayOfWeek == 3 (Tuesday)
// we need to add 2 "empty day cells" for Sunday and Monday
let totalCellsNeeded = numberOfDaysInMonth + (startDayOfWeek - 1)
// calculate number of rows needed -- this will be 4, 5 or 6
// the only time we get 4 is if Feb 1st in a non-leapYear falls on a Sunday
let numRows = Int(ceil(Double(totalCellsNeeded) / Double(7)))
// we now know the Height needed for the collection view
// you said your calendar cell height is 75, so...
// cvHeight = numRows * 75
We can put that in a loop and print() the information to the debug console like this:
override func viewDidLoad() {
super.viewDidLoad()
let calendar = Calendar.current
// 2026 is the next year where Feb starts on a Sunday
// so let's use that year to see that we get 4 rows for Feb
let year = 2026
for month in 1...12 {
let dateComponents = DateComponents(year: year, month: month)
// startDate will be the first date of the month (Jan 1, Feb 1, Mar 1, etc...)
guard let startDate = calendar.date(from: dateComponents) else {
fatalError("Something is wrong with the date!")
}
// get the range of days in the month
guard let range = calendar.range(of: .day, in: .month, for: startDate) else {
fatalError("Something is wrong with the date!")
}
// get number of days in the month
let numberOfDaysInMonth = range.count
// get the day of the week for the first date in the month
// this returns 1-based numbering
// Nov 1, 2020 was a Sunday, so this would return 1
let startDayOfWeek = Calendar.current.component(.weekday, from: startDate)
// add the "leading days to the start date"
// so, if startDayOfWeek == 3 (Tuesday)
// we need to add 2 "empty day cells" for Sunday and Monday
let totalCellsNeeded = numberOfDaysInMonth + (startDayOfWeek - 1)
// calculate number of rows needed -- this will be 4, 5 or 6
// the only time we get 4 is if Feb 1st in a non-leapYear falls on a Sunday
let numRows = Int(ceil(Double(totalCellsNeeded) / Double(7)))
// we now know the Height needed for the collection view
// you said your calendar cell height is 75, so...
// cvHeight = numRows * 75
// debug output
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "EEEE"
let dayName = dateFormatter.string(from: startDate)
dateFormatter.dateFormat = "LLLL y"
let dateString = dateFormatter.string(from: startDate)
let dayPadded = dayName.padding(toLength: 10, withPad: " ", startingAt: 0)
let datePadded = dateString.padding(toLength: 16, withPad: " ", startingAt: 0)
print("\(datePadded) has \(numberOfDaysInMonth) days, starting on \(dayPadded) requiring \(numRows) rows")
}
}
Here's the output:
January 2026 has 31 days, starting on Thursday requiring 5 rows
February 2026 has 28 days, starting on Sunday requiring 4 rows
March 2026 has 31 days, starting on Sunday requiring 5 rows
April 2026 has 30 days, starting on Wednesday requiring 5 rows
May 2026 has 31 days, starting on Friday requiring 6 rows
June 2026 has 30 days, starting on Monday requiring 5 rows
July 2026 has 31 days, starting on Wednesday requiring 5 rows
August 2026 has 31 days, starting on Saturday requiring 6 rows
September 2026 has 30 days, starting on Tuesday requiring 5 rows
October 2026 has 31 days, starting on Thursday requiring 5 rows
November 2026 has 30 days, starting on Sunday requiring 5 rows
December 2026 has 31 days, starting on Tuesday requiring 5 rows
So... either in:
cellForRowAt ... calculate the needed height and set the CV height in the cell, or
heightForRowAt ... calculate and return the needed height for the row
Side note: I'd suggest using auto-layout for all of your cells, instead of returning various row heights.
Related
I have implemented date picker in swift. I want to enable the date for next 7 day in calendar.How its is Possible.
You can set a maximum date within a UIDatePicker like this:
var datePicker = UIDatePicker()
datePicker.datePickerMode = .date
// set the start date to today if you don't want to allow dates in the past
datePicker.minimumDate = Date()
// calculate +7 days
let next7Days = Calendar.current.date(byAdding: .day, value: 7, to: Date())
//set maximum date
datePicker.maximumDate = next7Days
this will only allow to chose a date within the next 7 days
I develop my own app and I work on sign up screen.The person who sign up my app have to enter a birth date in my textfield and only user has 18-55 age accept.My textField has UIDatePicker.When datePicker open ,I want to show min and max date range.For example today now 12/02/2022 , datePicker have to show min date 12/02/2004 (user has 18) and show max date 1/1/1967 (user has 55).
https://imgur.com/a/DBpT5eq
first change the version checking line to
if #available(iOS 13.4,*) {
}
secondly use calendar for min max date
let datePicker = UIDatePicker()
if let eighteenAgo = Calendar.current.date(byAdding: .year, value: -18, to: Date()),
let afterFiftyFive = Calendar.current.date(byAdding: .year, value: 55, to: Date()) {
print(eighteenAgo.formatted(), ": Min")
print(afterFiftyFive.formatted(), ": Max")
datePicker.minimumDate = eighteenAgo
datePicker.maximumDate = afterFiftyFive
}
This question already has answers here:
How to scroll List programmatically in SwiftUI?
(10 answers)
Closed 9 months ago.
I have a List with 12 sections that represent the months of a year and each seach has the number of days of a month as an item. The problem is ScrollViewReader only scrolls the items of the first section. for example, January contains 31 days and it works when I call scroll.scrollTo(23, anchor: .center). How can I make scrollView scroll to a specific section 5 (June) and item 9 (today)?. Here is my code:
let daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30 ,31]
ScrollViewReader { scroll in
List {
Section("January") {
ForEach(0..<daysInMonth[0], id:\.self) {
CalendarRow(calendar: fetchCalendarData(section: 0, index: $0))
}
}
.
.
.
// and other sections to December
}
}
.onAppear {
withAnimation { scroll.scrollTo(ROW, anchor: .center) }
}
scrollTo(_:, anchor:) goes to a view with a specific ID. You aren't assigning any IDs to your views, so presumably you're accidentally taking advantage of some default. Make a specific ID for each day in each month (e.g. January-01 ... December-31) and assign that to each calendar row:
CalendarRow(...).id("June-09")
I am working in UIDatePicker iOS 14 with below config:
datePicker.datePickerMode = .dateAndTime
datePicker.preferredDatePickerStyle = .inline
datePicker.minimumDate = Date() // 29 Dec 2020 at 14:00
When I change the time value and the value smaller than the minimum date (Ex: 29 Dec 2020 at 12:00), the DatePicker updated UI but the value still keeps the minimum date. It's working normally in iOS 13: the date picker returns the minimum value when the change value is less than the minimum value.
Is this the bug of UIDatePicker in iOS?
I have a UICollectionView which consists of 12 cells from Jan to Dec as shown in the screenshot below:
How can I make the current month to always to be at the center of the collection view? For example, Dec shall be shown on the center for this month.
One of the solutions is to scroll automatically to the next page and center the 12th cell but how can I achieve that?
You can use the cellForItem function to define how the cells are going to appear and the UICollectionView function reloadData() to update all the cells always you think it's necessary.
If December should be the cell in the middle, make sure that 5 or 6 cells come before December, you should be able to do this with simple conditions inside cellForItem.
For example, as you have 12 cells, you can get the current month as and integer (12 for December), and you will know that the first month will be 12 - 6 = 6 (June), so you can do this calculation for each indexPath.
To simplify your job:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = ...
let month = GetCurrentMonthAsInteger()
var cellMonth = month - 6 + indexPath.row //or section if you have 12 sections
if(cellMonth < 1) {cellMonth = 12 + cellMonth}
else if(cellMonth > 12) {cellMonth = cellMonth - 12}
cell.setInformationForMonth(cellMonth)
...
return cell
}
You can try making min spacing to zero for cells and lines