Ability of multiple selection on PhotoLibraryViewController

ALCameraViewController/Utilities/ImageFetcher.swift

@@ -61,4 +61,20 @@ public class ImageFetcher {
             }
         }
     }
+
+    public static func resolveAssets(_ assets: [PHAsset], size: CGSize = CGSize(width: 720, height: 1280)) -> [UIImage] {
+        let imageManager = PHImageManager.default()
+        let requestOptions = PHImageRequestOptions()
+        requestOptions.isSynchronous = true
+
+        var images = [UIImage]()
+        for asset in assets {
+            imageManager.requestImage(for: asset, targetSize: size, contentMode: .aspectFill, options: requestOptions) { image, _ in
+                if let image = image {
+                    images.append(image)
+                }
+            }
+        }
+        return images
+    }
 }

ALCameraViewController/ViewController/CameraViewController.swift

@@ -41,6 +41,20 @@ public extension CameraViewController {
 
         return navigationController
     }
+
+    /// Provides an multiple image picker wrapped inside a UINavigationController instance
+    public class func imagePickerViewController(completion: @escaping PhotoLibraryViewMultipleSelectionComplete) -> UINavigationController {
+        let imagePicker = PhotoLibraryViewController()
+        imagePicker.allowsMultipleSelection = true
+        imagePicker.onMultipleSelectionComplete = completion
+
+        let navigationController = UINavigationController(rootViewController: imagePicker)
+        navigationController.navigationBar.barTintColor = UIColor.black
+        navigationController.navigationBar.barStyle = UIBarStyle.black
+        navigationController.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
+
+        return navigationController
+    }
 }
 
 open class CameraViewController: UIViewController {

ALCameraViewController/ViewController/PhotoLibraryViewController.swift

@@ -14,12 +14,16 @@ internal let ImageCellIdentifier = "ImageCell"
 internal let defaultItemSpacing: CGFloat = 1
 
 public typealias PhotoLibraryViewSelectionComplete = (PHAsset?) -> Void
+public typealias PhotoLibraryViewMultipleSelectionComplete = ([PHAsset]?) -> Void
 
 public class PhotoLibraryViewController: UIViewController {
 
     internal var assets: PHFetchResult<PHAsset>? = nil
 
+    /// Controls whether multiple cells can be selected, default is `false`.
+    public var allowsMultipleSelection = false
     public var onSelectionComplete: PhotoLibraryViewSelectionComplete?
+    public var onMultipleSelectionComplete: PhotoLibraryViewMultipleSelectionComplete?
 
     private lazy var collectionView: UICollectionView = {
         let layout = UICollectionViewFlowLayout()
@@ -32,6 +36,7 @@ public class PhotoLibraryViewController: UIViewController {
         let collectionView = UICollectionView(frame: CGRect.zero, collectionViewLayout: layout)
         collectionView.translatesAutoresizingMaskIntoConstraints = false
         collectionView.backgroundColor = UIColor.clear
+        collectionView.allowsMultipleSelection = self.allowsMultipleSelection
         return collectionView
     }()
 
@@ -47,6 +52,12 @@ public class PhotoLibraryViewController: UIViewController {
                                                            target: self,
                                                            action: #selector(dismissLibrary))
 
+        if allowsMultipleSelection {
+            navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done,
+                                                                target: self,
+                                                                action: #selector(selectMultiple))
+        }
+
         view.backgroundColor = UIColor(white: 0.2, alpha: 1)
         view.addSubview(collectionView)
 
@@ -73,7 +84,12 @@ public class PhotoLibraryViewController: UIViewController {
     }
 
     @objc public func dismissLibrary() {
-        onSelectionComplete?(nil)
+        allowsMultipleSelection ? onMultipleSelectionComplete?(nil) : onSelectionComplete?(nil)
+    }
+
+    @objc public func selectMultiple() {
+        let assets: [PHAsset]? = collectionView.indexPathsForSelectedItems?.flatMap { self.itemAtIndexPath($0) }
+        onMultipleSelectionComplete?(assets)
     }
 
     private func onSuccess(_ photos: PHFetchResult<PHAsset>) {
@@ -122,6 +138,23 @@ extension PhotoLibraryViewController : UICollectionViewDataSource {
 // MARK: - UICollectionViewDelegate -
 extension PhotoLibraryViewController : UICollectionViewDelegateFlowLayout {
     public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
+        guard !allowsMultipleSelection else {
+            return
+        }
         onSelectionComplete?(itemAtIndexPath(indexPath))
     }
+
+    public func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
+        guard allowsMultipleSelection else {
+            return true
+        }
+
+        if let selectedItems = collectionView.indexPathsForSelectedItems {
+            if selectedItems.contains(indexPath) {
+                collectionView.deselectItem(at: indexPath, animated: true)
+                return false
+            }
+        }
+        return true
+    }
 }

ALCameraViewController/Views/ImageCell.swift

@@ -42,6 +42,13 @@ class ImageCell: UICollectionViewCell {
                                   compatibleWith: nil)
     }
 
+    override var isSelected: Bool {
+        didSet {
+            contentView.layer.borderWidth = 2.0
+            contentView.layer.borderColor = isSelected ? UIColor.blue.cgColor : UIColor.clear.cgColor
+        }
+    }
+
     func configureWithModel(_ model: PHAsset) {
 
         if tag != 0 {

Example/ViewController.swift

@@ -23,7 +23,8 @@ class ViewController: UIViewController {
     @IBOutlet weak var imageView: UIImageView!
     @IBOutlet weak var croppingParametersView: UIView!
     @IBOutlet weak var minimumSizeLabel: UILabel!
-
+    @IBOutlet weak var multipleSelectionSwitch: UISwitch!
+
     override func viewDidLoad() {
         super.viewDidLoad()
 
@@ -40,12 +41,23 @@ class ViewController: UIViewController {
     }
 
     @IBAction func openLibrary(_ sender: Any) {
-        let libraryViewController = CameraViewController.imagePickerViewController(croppingParameters: croppingParameters) { [weak self] image, asset in
-            self?.imageView.image = image
-            self?.dismiss(animated: true, completion: nil)
+        if multipleSelectionSwitch.isOn  {
+            let libraryViewController = CameraViewController.imagePickerViewController(completion: { [weak self] assets in
+                if let assets = assets {
+                    let images = ImageFetcher.resolveAssets(assets, size: largestPhotoSize())
+                    self?.imageView.image = images.last
+                }
+                self?.dismiss(animated: true, completion: nil)
+            })
+            present(libraryViewController, animated: true, completion: nil)
+        } else {
+            let libraryViewController = CameraViewController.imagePickerViewController(croppingParameters: croppingParameters) {
+                [weak self] image, asset in
+                self?.imageView.image = image
+                self?.dismiss(animated: true, completion: nil)
+            }
+            present(libraryViewController, animated: true, completion: nil)
         }
-
-        present(libraryViewController, animated: true, completion: nil)
     }
 
     @IBAction func libraryChanged(_ sender: Any) {

Example/ViewController.xib

@@ -1,11 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="13529" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="13771" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" useSafeAreas="YES" colorMatched="YES">
     <device id="retina4_0" orientation="portrait">
         <adaptation id="fullscreen"/>
     </device>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13527"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="13772"/>
         <capability name="Safe area layout guides" minToolsVersion="9.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
@@ -20,6 +20,7 @@
                 <outlet property="croppingParametersView" destination="aZk-39-lei" id="iih-He-zYC"/>
                 <outlet property="imageView" destination="I4G-in-XtY" id="U1I-c7-fHk"/>
                 <outlet property="minimumSizeLabel" destination="DXi-q2-e5s" id="NxY-Mc-zZv"/>
+                <outlet property="multipleSelectionSwitch" destination="gVG-zP-Dbh" id="oTo-4p-JDL"/>
                 <outlet property="view" destination="iN0-l3-epB" id="NQI-AD-Uhb"/>
             </connections>
         </placeholder>
@@ -28,11 +29,8 @@
             <rect key="frame" x="0.0" y="0.0" width="320" height="568"/>
             <autoresizingMask key="autoresizingMask" flexibleMinX="YES" widthSizable="YES" flexibleMaxX="YES" flexibleMinY="YES" heightSizable="YES" flexibleMaxY="YES"/>
             <subviews>
-                <imageView userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="I4G-in-XtY">
-                    <rect key="frame" x="0.0" y="0.0" width="320" height="568"/>
-                </imageView>
                 <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="QHP-Db-zQM">
-                    <rect key="frame" x="0.0" y="0.0" width="320" height="118"/>
+                    <rect key="frame" x="0.0" y="0.0" width="320" height="177"/>
                     <subviews>
                         <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="cgD-PF-WNE">
                             <rect key="frame" x="70" y="48" width="41" height="29"/>
@@ -45,7 +43,7 @@
                             </connections>
                         </button>
                         <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Cropping" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="3e8-yb-h3L">
-                            <rect key="frame" x="258" y="85" width="53.5" height="17"/>
+                            <rect key="frame" x="258" y="85" width="54" height="17"/>
                             <fontDescription key="fontDescription" name="AppleSDGothicNeo-Regular" family="Apple SD Gothic Neo" pointSize="14"/>
                             <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                             <nil key="highlightedColor"/>
@@ -61,7 +59,7 @@
                             </connections>
                         </button>
                         <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="kvv-7d-Re7">
-                            <rect key="frame" x="260.5" y="48" width="51" height="31"/>
+                            <rect key="frame" x="261" y="48" width="51" height="31"/>
                             <connections>
                                 <action selector="croppingChanged:" destination="-1" eventType="valueChanged" id="fjU-Hs-bwf"/>
                             </connections>
@@ -73,7 +71,16 @@
                             </connections>
                         </switch>
                         <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Library Access" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="VFc-CF-Vtc">
-                            <rect key="frame" x="158" y="85" width="84.5" height="17"/>
+                            <rect key="frame" x="158" y="85" width="85" height="17"/>
+                            <fontDescription key="fontDescription" name="AppleSDGothicNeo-Regular" family="Apple SD Gothic Neo" pointSize="14"/>
+                            <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                            <nil key="highlightedColor"/>
+                        </label>
+                        <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="gVG-zP-Dbh">
+                            <rect key="frame" x="176" y="110" width="51" height="31"/>
+                        </switch>
+                        <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Multiple Selection" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="5Bq-QY-3gS">
+                            <rect key="frame" x="148" y="148" width="105" height="17"/>
                             <fontDescription key="fontDescription" name="AppleSDGothicNeo-Regular" family="Apple SD Gothic Neo" pointSize="14"/>
                             <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                             <nil key="highlightedColor"/>
@@ -82,12 +89,16 @@
                     <color key="backgroundColor" red="1" green="1" blue="1" alpha="0.29999999999999999" colorSpace="custom" customColorSpace="sRGB"/>
                     <constraints>
                         <constraint firstItem="kvv-7d-Re7" firstAttribute="centerX" secondItem="3e8-yb-h3L" secondAttribute="centerX" id="03O-8V-75Q"/>
+                        <constraint firstItem="5Bq-QY-3gS" firstAttribute="centerX" secondItem="gVG-zP-Dbh" secondAttribute="centerX" id="1fg-i4-G4k"/>
                         <constraint firstItem="3e8-yb-h3L" firstAttribute="leading" secondItem="VFc-CF-Vtc" secondAttribute="trailing" constant="15.5" id="4Jt-tB-SUL"/>
-                        <constraint firstAttribute="bottom" secondItem="3e8-yb-h3L" secondAttribute="bottom" constant="16" id="5p4-dS-pea"/>
+                        <constraint firstAttribute="bottom" secondItem="3e8-yb-h3L" secondAttribute="bottom" constant="75" id="5p4-dS-pea"/>
                         <constraint firstItem="VFc-CF-Vtc" firstAttribute="top" secondItem="JPj-mG-Hu1" secondAttribute="bottom" constant="6" id="6Pj-pH-zeh"/>
                         <constraint firstItem="JPj-mG-Hu1" firstAttribute="top" secondItem="kvv-7d-Re7" secondAttribute="top" id="7aB-or-fz9"/>
                         <constraint firstItem="JPj-mG-Hu1" firstAttribute="centerX" secondItem="VFc-CF-Vtc" secondAttribute="centerX" id="9gI-Mi-9w4"/>
+                        <constraint firstItem="gVG-zP-Dbh" firstAttribute="top" secondItem="VFc-CF-Vtc" secondAttribute="bottom" constant="8" symbolic="YES" id="Ko5-KT-AwX"/>
                         <constraint firstItem="3e8-yb-h3L" firstAttribute="top" secondItem="kvv-7d-Re7" secondAttribute="bottom" constant="6" id="SdV-Ft-rmy"/>
+                        <constraint firstItem="gVG-zP-Dbh" firstAttribute="trailing" secondItem="JPj-mG-Hu1" secondAttribute="trailing" id="UQx-B3-kh2"/>
+                        <constraint firstItem="5Bq-QY-3gS" firstAttribute="top" secondItem="gVG-zP-Dbh" secondAttribute="bottom" constant="7" id="Wjn-jU-jjU"/>
                         <constraint firstAttribute="trailing" secondItem="3e8-yb-h3L" secondAttribute="trailing" constant="8.5" id="ZKC-Ah-kcn"/>
                         <constraint firstItem="kvv-7d-Re7" firstAttribute="top" secondItem="YHP-W6-S2W" secondAttribute="top" id="bj8-Oa-dOs"/>
                         <constraint firstItem="cgD-PF-WNE" firstAttribute="centerY" secondItem="YHP-W6-S2W" secondAttribute="centerY" id="cYp-Ej-9Ae"/>
@@ -121,7 +132,7 @@
                             </connections>
                         </slider>
                         <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Minimum size: 60" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="DXi-q2-e5s">
-                            <rect key="frame" x="185" y="64" width="105.5" height="17"/>
+                            <rect key="frame" x="184" y="64" width="106" height="17"/>
                             <fontDescription key="fontDescription" name="AppleSDGothicNeo-Regular" family="Apple SD Gothic Neo" pointSize="14"/>
                             <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                             <nil key="highlightedColor"/>
@@ -166,6 +177,9 @@
                         <constraint firstItem="k5h-ry-m8S" firstAttribute="centerX" secondItem="In7-Or-H5s" secondAttribute="centerX" id="z4S-xt-ZNI"/>
                     </constraints>
                 </view>
+                <imageView userInteractionEnabled="NO" contentMode="scaleAspectFit" horizontalHuggingPriority="251" verticalHuggingPriority="251" translatesAutoresizingMaskIntoConstraints="NO" id="I4G-in-XtY">
+                    <rect key="frame" x="0.0" y="0.0" width="320" height="568"/>
+                </imageView>
             </subviews>
             <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
             <constraints>