Allow backwards selection of date range.

.swift-version

@@ -1 +1 @@
-3.0
+4.2

CalendarDateRangePickerViewController.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'CalendarDateRangePickerViewController'
-  s.version          = '0.1.0'
+  s.version          = '0.3.0'
   s.summary          = 'A calendar date range picker view controller in Swift for iOS.'
 
 # This description is used to generate tags and improve search results.
@@ -39,4 +39,6 @@ This is a calendar date range picker view controller written in Swift for iOS. T
   # s.public_header_files = 'Pod/Classes/**/*.h'
   # s.frameworks = 'UIKit', 'MapKit'
   # s.dependency 'AFNetworking', '~> 2.3'
+
+  s.swift_version = '4.2'
 end

CalendarDateRangePickerViewController/Classes/CalendarDateRangePickerCell.swift

@@ -11,9 +11,13 @@ import UIKit
 class CalendarDateRangePickerCell: UICollectionViewCell {
 
     private let defaultTextColor = UIColor.darkGray
-    private let highlightedColor = UIColor(white: 0.9, alpha: 1.0)
+    var highlightedColor = UIColor(white: 0.9, alpha: 1.0)
     private let disabledColor = UIColor.lightGray
-
+    var font = UIFont(name: "HelveticaNeue", size: CalendarDateRangePickerViewController.defaultCellFontSize) {
+        didSet {
+            label?.font = font
+        }
+    }
     var selectedColor: UIColor!
 
     var date: Date?
@@ -36,7 +40,7 @@ class CalendarDateRangePickerCell: UICollectionViewCell {
     func initLabel() {
         label = UILabel(frame: frame)
         label.center = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
-        label.font = UIFont(name: "HelveticaNeue", size: 15.0)
+        label.font = font
         label.textColor = UIColor.darkGray
         label.textAlignment = NSTextAlignment.center
         self.addSubview(label)
@@ -67,7 +71,7 @@ class CalendarDateRangePickerCell: UICollectionViewCell {
         selectedView?.backgroundColor = selectedColor
         selectedView?.layer.cornerRadius = height / 2
         self.addSubview(selectedView!)
-        self.sendSubview(toBack: selectedView!)
+        self.sendSubviewToBack(selectedView!)
 
         label.textColor = UIColor.white
     }
@@ -79,7 +83,7 @@ class CalendarDateRangePickerCell: UICollectionViewCell {
         halfBackgroundView = UIView(frame: CGRect(x: width / 2, y: 0, width: width / 2, height: height))
         halfBackgroundView?.backgroundColor = highlightedColor
         self.addSubview(halfBackgroundView!)
-        self.sendSubview(toBack: halfBackgroundView!)
+        self.sendSubviewToBack(halfBackgroundView!)
 
         addRoundHighlightView()
     }
@@ -91,7 +95,7 @@ class CalendarDateRangePickerCell: UICollectionViewCell {
         halfBackgroundView = UIView(frame: CGRect(x: 0, y: 0, width: width / 2, height: height))
         halfBackgroundView?.backgroundColor = highlightedColor
         self.addSubview(halfBackgroundView!)
-        self.sendSubview(toBack: halfBackgroundView!)
+        self.sendSubviewToBack(halfBackgroundView!)
 
         addRoundHighlightView()
     }
@@ -103,7 +107,7 @@ class CalendarDateRangePickerCell: UICollectionViewCell {
         roundHighlightView?.backgroundColor = highlightedColor
         roundHighlightView?.layer.cornerRadius = height / 2
         self.addSubview(roundHighlightView!)
-        self.sendSubview(toBack: roundHighlightView!)
+        self.sendSubviewToBack(roundHighlightView!)
     }
 
     func highlight() {

CalendarDateRangePickerViewController/Classes/CalendarDateRangePickerHeaderView.swift

@@ -11,6 +11,11 @@ import UIKit
 class CalendarDateRangePickerHeaderView: UICollectionReusableView {
 
     var label: UILabel!
+    var font = UIFont(name: "HelveticaNeue-Light", size: CalendarDateRangePickerViewController.defaultHeaderFontSize) {
+        didSet {
+            label?.font = font
+        }
+    }
 
     override init(frame: CGRect) {
         super.init(frame: frame)
@@ -24,11 +29,14 @@ class CalendarDateRangePickerHeaderView: UICollectionReusableView {
 
     func initLabel() {
         label = UILabel(frame: frame)
-        label.center = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
-        label.font = UIFont(name: "HelveticaNeue-Light", size: 17.0)
+        label.font = font
         label.textColor = UIColor.darkGray
         label.textAlignment = NSTextAlignment.center
         self.addSubview(label)
     }
 
+    override func layoutSubviews() {
+        super.layoutSubviews()
+        label.center = CGPoint(x: frame.size.width / 2, y: frame.size.height / 2)
+    }
 }

CalendarDateRangePickerViewController/Classes/CalendarDateRangePickerViewController.swift

@@ -11,6 +11,18 @@ import UIKit
 public protocol CalendarDateRangePickerViewControllerDelegate {
     func didCancelPickingDateRange()
     func didPickDateRange(startDate: Date!, endDate: Date!)
+
+    // Optional
+    func didPickDate(date: Date)
+    func calendarViewDidLayoutSubviews()
+    func calendarViewWillLayoutSubviews()
+}
+
+public extension CalendarDateRangePickerViewControllerDelegate {
+    // Making these optional. For backwards compatiblity.
+    func didPickDate(date: Date) {}
+    func calendarViewDidLayoutSubviews() {}
+    func calendarViewWillLayoutSubviews() {}
 }
 
 public class CalendarDateRangePickerViewController: UICollectionViewController {
@@ -22,17 +34,41 @@ public class CalendarDateRangePickerViewController: UICollectionViewController {
 
     let itemsPerRow = 7
     let itemHeight: CGFloat = 40
-    let collectionViewInsets = UIEdgeInsets(top: 0, left: 25, bottom: 0, right: 25)
+
+    // 3/20/18; Changed from `let` to `var`, and made public, to allow Cocoapod user to change insets.
+    public var collectionViewInsets = UIEdgeInsets(top: 0, left: 25, bottom: 0, right: 25)
+
+    // Allow the user select "backwards" in the calendar? E.g., say I select March 16 first and then want to select March 14 for range of March 14 to March 16. Default is `false` because this was the original behavior of this Cocoapod.
+    public var allowBackwardSelection: Bool = false
+
+    // Only allow a single date (not a date range) to be selected. Default behavior is not to allow this.
+    public var onlySingleDateSelection: Bool = false
+
+    // If you set this to false, then you get a callback for date selection on every tap. `true` is the original behavior of this Cocoapod.
+    public var requireDone: Bool = true
+
+    fileprivate var calendar:Calendar = Calendar.current
+    public var timezone: TimeZone = TimeZone.current {
+        didSet {
+            calendar.timeZone = timezone
+        }
+    }
 
     public var minimumDate: Date!
     public var maximumDate: Date!
 
     public var selectedStartDate: Date?
     public var selectedEndDate: Date?
 
+    public var cellHighlightedColor = UIColor(white: 0.9, alpha: 1.0)
+    public static let defaultCellFontSize:CGFloat = 15.0
+    public static let defaultHeaderFontSize:CGFloat = 17.0
+    public var cellFont:UIFont = UIFont(name: "HelveticaNeue", size: CalendarDateRangePickerViewController.defaultCellFontSize)!
+    public var headerFont:UIFont = UIFont(name: "HelveticaNeue-Light", size: CalendarDateRangePickerViewController.defaultHeaderFontSize)!
+
     public var selectedColor = UIColor(red: 66/255.0, green: 150/255.0, blue: 240/255.0, alpha: 1.0)
     public var titleText = "Select Dates"
-
+    
     override public func viewDidLoad() {
         super.viewDidLoad()
 
@@ -43,40 +79,55 @@ public class CalendarDateRangePickerViewController: UICollectionViewController {
         collectionView?.backgroundColor = UIColor.white
 
         collectionView?.register(CalendarDateRangePickerCell.self, forCellWithReuseIdentifier: cellReuseIdentifier)
-        collectionView?.register(CalendarDateRangePickerHeaderView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: headerReuseIdentifier)
+        collectionView?.register(CalendarDateRangePickerHeaderView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: headerReuseIdentifier)
         collectionView?.contentInset = collectionViewInsets
 
         if minimumDate == nil {
             minimumDate = Date()
         }
         if maximumDate == nil {
-            maximumDate = Calendar.current.date(byAdding: .year, value: 3, to: minimumDate)
+            maximumDate = calendar.date(byAdding: .year, value: 3, to: minimumDate)
         }
 
         self.navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Cancel", style: .plain, target: self, action: #selector(CalendarDateRangePickerViewController.didTapCancel))
         self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "Done", style: .done, target: self, action: #selector(CalendarDateRangePickerViewController.didTapDone))
         self.navigationItem.rightBarButtonItem?.isEnabled = selectedStartDate != nil && selectedEndDate != nil
     }
 
-    func didTapCancel() {
+    override public func viewDidLayoutSubviews() {
+        super.viewDidLayoutSubviews()
+        delegate.calendarViewDidLayoutSubviews()
+    }
+
+    override public func viewWillLayoutSubviews() {
+        super.viewWillLayoutSubviews()
+        delegate.calendarViewWillLayoutSubviews()
+    }
+
+    @objc func didTapCancel() {
         delegate.didCancelPickingDateRange()
     }
 
-    func didTapDone() {
-        if selectedStartDate == nil || selectedEndDate == nil {
+    @objc func didTapDone() {
+        if selectedStartDate == nil {
+            return
+        }
+
+        if selectedEndDate == nil {
+            delegate.didPickDate(date: selectedStartDate!)
             return
         }
+
         delegate.didPickDateRange(startDate: selectedStartDate!, endDate: selectedEndDate!)
     }
-
 }
 
 extension CalendarDateRangePickerViewController {
 
     // UICollectionViewDataSource
 
     override public func numberOfSections(in collectionView: UICollectionView) -> Int {
-        let difference = Calendar.current.dateComponents([.month], from: minimumDate, to: maximumDate)
+        let difference = calendar.dateComponents([.month], from: minimumDate, to: maximumDate)
         return difference.month! + 1
     }
 
@@ -90,7 +141,9 @@ extension CalendarDateRangePickerViewController {
 
     override public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
         let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellReuseIdentifier, for: indexPath) as! CalendarDateRangePickerCell
+        cell.highlightedColor = self.cellHighlightedColor
         cell.selectedColor = self.selectedColor
+        cell.font = self.cellFont
         cell.reset()
         let blankItems = getWeekday(date: getFirstDateForSection(section: indexPath.section)) - 1
         if indexPath.item < 7 {
@@ -132,9 +185,10 @@ extension CalendarDateRangePickerViewController {
 
     override public func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
         switch kind {
-        case UICollectionElementKindSectionHeader:
+        case UICollectionView.elementKindSectionHeader:
             let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: headerReuseIdentifier, for: indexPath) as! CalendarDateRangePickerHeaderView
             headerView.label.text = getMonthLabel(date: getFirstDateForSection(section: indexPath.section))
+            headerView.font = headerFont
             return headerView
         default:
             fatalError("Unexpected element kind")
@@ -144,6 +198,11 @@ extension CalendarDateRangePickerViewController {
 }
 
 extension CalendarDateRangePickerViewController : UICollectionViewDelegateFlowLayout {
+    func didPickDateRangeIfNeeded() {
+        if !requireDone {
+            didTapDone()
+        }
+    }
 
     override public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
         let cell = collectionView.cellForItem(at: indexPath) as! CalendarDateRangePickerCell
@@ -153,20 +212,29 @@ extension CalendarDateRangePickerViewController : UICollectionViewDelegateFlowLa
         if isBefore(dateA: cell.date!, dateB: minimumDate) {
             return
         }
-        if selectedStartDate == nil {
+        if selectedStartDate == nil || onlySingleDateSelection {
             selectedStartDate = cell.date
         } else if selectedEndDate == nil {
             if isBefore(dateA: selectedStartDate!, dateB: cell.date!) {
                 selectedEndDate = cell.date
                 self.navigationItem.rightBarButtonItem?.isEnabled = true
             } else {
-                // If a cell before the currently selected start date is selected then just set it as the new start date
-                selectedStartDate = cell.date
+                if allowBackwardSelection && selectedStartDate != cell.date {
+                    selectedEndDate = selectedStartDate
+                    selectedStartDate = cell.date
+                }
+                else {
+                    // If a cell before the currently selected start date is selected then just set it as the new start date
+                    selectedStartDate = cell.date
+                }
             }
         } else {
             selectedStartDate = cell.date
             selectedEndDate = nil
         }
+
+        didPickDateRangeIfNeeded()
+
         collectionView.reloadData()
     }
 
@@ -198,54 +266,56 @@ extension CalendarDateRangePickerViewController {
     // Helper functions
 
     func getFirstDate() -> Date {
-        var components = Calendar.current.dateComponents([.month, .year], from: minimumDate)
+        var components = calendar.dateComponents([.month, .year], from: minimumDate)
         components.day = 1
-        return Calendar.current.date(from: components)!
+        return calendar.date(from: components)!
     }
 
     func getFirstDateForSection(section: Int) -> Date {
-        return Calendar.current.date(byAdding: .month, value: section, to: getFirstDate())!
+        return calendar.date(byAdding: .month, value: section, to: getFirstDate())!
     }
 
     func getMonthLabel(date: Date) -> String {
         let dateFormatter = DateFormatter()
+        dateFormatter.timeZone = timezone
         dateFormatter.dateFormat = "MMMM yyyy"
         return dateFormatter.string(from: date)
     }
 
     func getWeekdayLabel(weekday: Int) -> String {
         var components = DateComponents()
-        components.calendar = Calendar.current
+        components.calendar = calendar
         components.weekday = weekday
-        let date = Calendar.current.nextDate(after: Date(), matching: components, matchingPolicy: Calendar.MatchingPolicy.strict)
+        let date = calendar.nextDate(after: Date(), matching: components, matchingPolicy: Calendar.MatchingPolicy.strict)
         if date == nil {
             return "E"
         }
         let dateFormatter = DateFormatter()
+        dateFormatter.timeZone = timezone
         dateFormatter.dateFormat = "EEEEE"
         return dateFormatter.string(from: date!)
     }
 
     func getWeekday(date: Date) -> Int {
-        return Calendar.current.dateComponents([.weekday], from: date).weekday!
+        return calendar.dateComponents([.weekday], from: date).weekday!
     }
 
     func getNumberOfDaysInMonth(date: Date) -> Int {
-        return Calendar.current.range(of: .day, in: .month, for: date)!.count
+        return calendar.range(of: .day, in: .month, for: date)!.count
     }
 
     func getDate(dayOfMonth: Int, section: Int) -> Date {
-        var components = Calendar.current.dateComponents([.month, .year], from: getFirstDateForSection(section: section))
+        var components = calendar.dateComponents([.month, .year], from: getFirstDateForSection(section: section))
         components.day = dayOfMonth
-        return Calendar.current.date(from: components)!
+        return calendar.date(from: components)!
     }
 
     func areSameDay(dateA: Date, dateB: Date) -> Bool {
-        return Calendar.current.compare(dateA, to: dateB, toGranularity: .day) == ComparisonResult.orderedSame
+        return calendar.compare(dateA, to: dateB, toGranularity: .day) == ComparisonResult.orderedSame
     }
 
     func isBefore(dateA: Date, dateB: Date) -> Bool {
-        return Calendar.current.compare(dateA, to: dateB, toGranularity: .day) == ComparisonResult.orderedAscending
+        return calendar.compare(dateA, to: dateB, toGranularity: .day) == ComparisonResult.orderedAscending
     }
 
 }