FSCalendar - create segue from day selected to another view controller

Question

I am a beginner in writing iOS apps and am currently working on a calendar app using FSCalendar. I want my app to go to the next view controller whenever I tap on the selected day on the FSCalendar (to show details about events on the selected day) but I couldn't find a way to create a segue that connects from the selected day to the view controller.

If segue is the way to go in this case, how do I make one? But if segue isn't the way to do it, please give some suggestions of other possible solutions. Thank you in advance!

Answer 1

FSCalendar has a "did select date" delegate function. If you are looking at the Swift Storyboard Sample, it is called and prints a formatted date to the debug console. That's where you can trigger your segue.

Start by adding a "Detail" view controller class:

//
//  DetailViewController.swift
//  FSCalendarSwiftExample
//
//  Created by Don Mag on 8/31/20.
//

import UIKit

class DetailViewController: UIViewController {

    var selectedDate: Date?
    
    @IBOutlet var myLabel: UILabel!
    
    fileprivate let formatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "yyyy/MM/dd"
        return formatter
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        if let d = selectedDate {
            myLabel.text = formatter.string(from: d)
        }
    }

}

Add a view controller to the Storyboard with a couple labels, set its class to DetailViewController, and connect the "Detail Label" to the myLabel @IBOutlet:

Ctrl-Drag from the view controller icon at the top of the FSCalendar view controller to your new Detail View Controller, and select Show from the popup menu:

You'll see that a segue has been added. Select that segue and give it an identifier of "gotoDetail":

In InterfaceBuilderViewController class, find this func:

func calendar(_ calendar: FSCalendar, didSelect date: Date, at monthPosition: FSCalendarMonthPosition) {
    print("calendar did select date \(self.formatter.string(from: date))")
    if monthPosition == .previous || monthPosition == .next {
        calendar.setCurrentPage(date, animated: true)
    }
}

and add a performSegue line at the end:

func calendar(_ calendar: FSCalendar, didSelect date: Date, at monthPosition: FSCalendarMonthPosition) {
    print("calendar did select date \(self.formatter.string(from: date))")
    if monthPosition == .previous || monthPosition == .next {
        calendar.setCurrentPage(date, animated: true)
    }
    // add this line
    self.performSegue(withIdentifier: "gotoDetail", sender: nil)
}

still in InterfaceBuilderViewController class, find the prepare(for segue... func:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let config = segue.destination as? CalendarConfigViewController {
        config.lunar = self.lunar
        config.theme = self.theme
        config.selectedDate = self.calendar.selectedDate
        config.firstWeekday = self.calendar.firstWeekday
        config.scrollDirection = self.calendar.scrollDirection
    }
}

and add this code at the end:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let config = segue.destination as? CalendarConfigViewController {
        config.lunar = self.lunar
        config.theme = self.theme
        config.selectedDate = self.calendar.selectedDate
        config.firstWeekday = self.calendar.firstWeekday
        config.scrollDirection = self.calendar.scrollDirection
    }
    // add this code
    if let detail = segue.destination as? DetailViewController {
        detail.selectedDate = calendar.selectedDate
    }
}

Run the app, select Interface Builder from the table view, and select a date. Your new Detail controller should be pushed into view, and it should display your selected date.