ADDED: Support for multiple date selections.

Calendar/CalendarKit/CalendarView.swift

@@ -11,8 +11,9 @@ import UIKit
 // 12 months - base date - 12 months
 let kMonthRange = 12
 
-protocol CalendarViewDelegate: class {
+@objc protocol CalendarViewDelegate: class {
     func didSelectDate(date: NSDate)
+    optional func didChangeSelectedDates(selectedDates: [NSDate])
 }
 
 class CalendarView: UIView, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout, UIScrollViewDelegate, MonthCollectionCellDelegate {
@@ -47,30 +48,43 @@ class CalendarView: UIView, UICollectionViewDataSource, UICollectionViewDelegate
         }
     }
 
-    var selectedDate: NSDate? {
+    var selectedDates: [NSDate] = [NSDate]() {
         didSet {
             collectionView.reloadData()
             dispatch_async(dispatch_get_main_queue()){
                 self.moveToSelectedDate(false)
-                if self.delegate != nil {
-                    self.delegate!.didSelectDate(self.selectedDate!)
+                if self.delegate != nil && self.selectedDates.count > 0 {
+                    self.delegate!.didSelectDate(self.selectedDates.last!)
+                    self.delegate!.didChangeSelectedDates?(self.selectedDates)
                 }
             }
         }
     }
+
+    var allowMultipleSelections = false
 
     override func awakeFromNib() {
         let nib = UINib(nibName: "MonthCollectionCell", bundle: nil)
         self.collectionView.registerNib(nib, forCellWithReuseIdentifier: "MonthCollectionCell")
     }
 
     class func instance(baseDate: NSDate, selectedDate: NSDate) -> CalendarView {
+        return instance(baseDate, selectedDates: [selectedDate])
+    }
+
+    class func instance(baseDate: NSDate, selectedDates: [NSDate]) -> CalendarView {
         let calendarView = NSBundle.mainBundle().loadNibNamed("CalendarView", owner: nil, options: nil).first as! CalendarView
-        calendarView.selectedDate = selectedDate
+         selectedDates.forEach({ (date) -> () in
+            calendarView.selectedDates.append(date.startOfDay)
+        })
+        if calendarView.selectedDates.count == 0 {
+            calendarView.selectedDates.append(NSDate().startOfDay)
+        }
         calendarView.baseDate = baseDate
         return calendarView
     }
 
+
     func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
         return collectionData.count
     }
@@ -82,8 +96,11 @@ class CalendarView: UIView, UICollectionViewDataSource, UICollectionViewDelegate
         cell.monthCellDelgate = self
 
         cell.logic = collectionData[indexPath.item]
-        if cell.logic!.isVisible(selectedDate!) {
-            cell.selectedDate = Date(date: selectedDate!)
+        cell.selectedDates.removeAll()
+        for date in selectedDates {
+            if cell.logic!.isVisible(date) {
+                cell.selectedDates.append(Date(date: date))
+            }
         }
 
         return cell
@@ -140,7 +157,7 @@ class CalendarView: UIView, UICollectionViewDataSource, UICollectionViewDelegate
         var index = -1
         for var i = 0; i < collectionData.count; i++  {
             let logic = collectionData[i]
-            if logic.containsDate(selectedDate!) {
+            if selectedDates.count > 0 && logic.containsDate(selectedDates.last!) {
                 index = i
                 break
             }
@@ -155,6 +172,25 @@ class CalendarView: UIView, UICollectionViewDataSource, UICollectionViewDelegate
 
     //MARK: Month cell delegate.
     func didSelect(date: Date) {
-        selectedDate = date.nsdate
+        if !allowMultipleSelections {
+            selectedDates[0] = date.nsdate.startOfDay
+        }
+        else {
+            selectedDates.append(date.nsdate.startOfDay)
+        }
+    }
+
+    func didDeselect(date: Date) {
+        if selectedDates.count == 1 {
+            return
+        }
+
+        for aDate in selectedDates {
+            if aDate.isSameDay(date.nsdate.startOfDay) {
+                if let index = selectedDates.indexOf(aDate) {
+                    selectedDates.removeAtIndex(index)
+                }
+            }
+        }
     }
 }

Calendar/CalendarKit/MonthCollectionCell.swift

@@ -10,6 +10,7 @@ import UIKit
 
 protocol MonthCollectionCellDelegate: class {
     func didSelect(date: Date)
+    func didDeselect(date: Date)
 }
 
 class MonthCollectionCell: UICollectionViewCell, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
@@ -31,7 +32,7 @@ class MonthCollectionCell: UICollectionViewCell, UICollectionViewDataSource, UIC
         }
     }
 
-    var selectedDate: Date? {
+    var selectedDates: [Date] = [Date]() {
         didSet {
             if collectionView != nil {
                 collectionView.reloadData()
@@ -78,8 +79,7 @@ class MonthCollectionCell: UICollectionViewCell, UICollectionViewDataSource, UIC
         let date = dates[indexPath.item]
 
         cell.date = (indexPath.item < dates.count) ? date : nil
-        cell.mark = (selectedDate == date)
-
+        cell.mark = selectedDates.contains(date)
         cell.disabled = (indexPath.item < previousMonthVisibleDatesCount) ||
                         (indexPath.item >= previousMonthVisibleDatesCount
                             + currentMonthVisibleDatesCount)
@@ -89,10 +89,15 @@ class MonthCollectionCell: UICollectionViewCell, UICollectionViewDataSource, UIC
 
     func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
         if monthCellDelgate != nil {
-            monthCellDelgate!.didSelect(dates[indexPath.item])
+            if selectedDates.contains(dates[indexPath.item]) {
+                monthCellDelgate!.didDeselect(dates[indexPath.item])
+            }
+            else {
+                monthCellDelgate!.didSelect(dates[indexPath.item])
+            }
         }
     }
-    
+
     func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
         return collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: "WeekHeaderView", forIndexPath: indexPath) 
     }

Calendar/CalendarKit/NSDateAdditions.swift

@@ -91,6 +91,10 @@ extension NSDate {
     var hour: Int {
         return components.hour
     }
+
+    func isSameDay(date: NSDate) -> Bool {
+        return !(self.year != date.year || self.month != date.month || self.day != date.day)
+    }
 
     //MARK: Private variable and methods.
 

Calendar/ViewController.swift

@@ -24,15 +24,32 @@ class ViewController: UIViewController, CalendarViewDelegate {
         let calendarView = CalendarView.instance(date, selectedDate: date)
         calendarView.delegate = self
         calendarView.translatesAutoresizingMaskIntoConstraints = false
+
+//        calendarView.allowMultipleSelections = true   //Allows selection of multiple dates. Defaults to false
+
         placeholderView.addSubview(calendarView)
 
         // Constraints for calendar view - Fill the parent view.
         placeholderView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[calendarView]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["calendarView": calendarView]))
         placeholderView.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[calendarView]|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["calendarView": calendarView]))
     }
 
+    //REQUIRED: Will be called whether allowMultipleSelections is true or false.
+    //Also will be called in cases of selection and deselection.
+    // Will return the last SELECTED date available
     func didSelectDate(date: NSDate) {
         print("\(date.year)-\(date.month)-\(date.day)")
     }
+
+    //OPTIONAL: Will return all selected dates. Useful when allowMultipleSelections is true
+    /*
+    func didChangeSelectedDates(selectedDates: [NSDate]) {
+        print("Selected Dates: {")
+        selectedDates.forEach { (date) -> () in
+            print("\(date.year)-\(date.month)-\(date.day)")
+        }
+        print("}")
+    }
+    */
 }