add collectionview size for cell size calculation

Author: Igor Vedeneev

CollectionKit.xcodeproj/project.pbxproj

@@ -26,6 +26,7 @@
 		D638A9081F9D25EE00B858E9 /* CollectionItem.swift in Sources */ = {isa = PBXBuildFile; fileRef = D69EEF7C1F689911002B29E4 /* CollectionItem.swift */; };
 		D638A9091F9D25EE00B858E9 /* CollectionSection.swift in Sources */ = {isa = PBXBuildFile; fileRef = D69EEF801F690F70002B29E4 /* CollectionSection.swift */; };
 		D638A90A1F9D25EE00B858E9 /* Helpers.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6CBBEB01F82F048007CD4A7 /* Helpers.swift */; };
+		D66BFA951FD3648E0095EC38 /* Header.swift in Sources */ = {isa = PBXBuildFile; fileRef = D66BFA941FD3648E0095EC38 /* Header.swift */; };
 		D681B53D1FC4D0E10015A2CF /* CollectionUpdater.swift in Sources */ = {isa = PBXBuildFile; fileRef = D681B53C1FC4D0E10015A2CF /* CollectionUpdater.swift */; };
 		D69EEF6E1F6894F5002B29E4 /* CollectionKitTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D69EEF6D1F6894F5002B29E4 /* CollectionKitTests.swift */; };
 		D6EF701C1FAA7CFD00164BA9 /* Localizable.strings in Resources */ = {isa = PBXBuildFile; fileRef = D6EF701E1FAA7CFD00164BA9 /* Localizable.strings */; };
@@ -77,6 +78,7 @@
 		D638A8FD1F9D25AF00B858E9 /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
 		D638A9001F9D25AF00B858E9 /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		D638A9021F9D25AF00B858E9 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		D66BFA941FD3648E0095EC38 /* Header.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Header.swift; sourceTree = "<group>"; };
 		D681B53C1FC4D0E10015A2CF /* CollectionUpdater.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CollectionUpdater.swift; sourceTree = "<group>"; };
 		D69EEF581F6894F5002B29E4 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = AppDelegate.swift; path = ../CollectionKit/AppDelegate.swift; sourceTree = "<group>"; };
 		D69EEF5A1F6894F5002B29E4 /* ViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = ViewController.swift; path = ../CollectionKit/ViewController.swift; sourceTree = "<group>"; };
@@ -171,6 +173,7 @@
 				D638A9021F9D25AF00B858E9 /* Info.plist */,
 				D619850F1FCB201E00D6BCB1 /* CellFromXIB.swift */,
 				D61985111FCB235C00D6BCB1 /* CellFromXIB.xib */,
+				D66BFA941FD3648E0095EC38 /* Header.swift */,
 			);
 			path = Examples;
 			sourceTree = "<group>";
@@ -396,6 +399,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D66BFA951FD3648E0095EC38 /* Header.swift in Sources */,
 				D6077EF91F9FF38600DD8CA6 /* ViewController.swift in Sources */,
 				D6077EFA1F9FF38600DD8CA6 /* AppDelegate.swift in Sources */,
 				D6077EFB1F9FF38600DD8CA6 /* CollectionCell.swift in Sources */,

CollectionKit/CollectionCell.swift

@@ -34,8 +34,8 @@ class CollectionCell: UICollectionViewCell {
 }
 
 extension CollectionCell : ConfigurableCollectionItem {
-    static func estimatedSize(item: String?) -> CGSize {
-        return CGSize(width: UIScreen.main.bounds.width, height: 50)
+    static func estimatedSize(item: String?, collectionViewSize: CGSize) -> CGSize {
+        return CGSize(width: collectionViewSize.width, height: 50)
     }
 
     func configure(item: String) {

CollectionKit/CollectionDirector.swift

@@ -27,7 +27,7 @@ import UIKit
 open class CollectionDirector: NSObject {
     public var sections = [AbstractCollectionSection]()
     open var shouldUseAutomaticCellRegistration: Bool = false
-    ///Adjust z position for headers/footers @ iOS11
+    ///Adjust z position for headers/footers to prevent scroll indicator hiding at iOS11
     open var shouldAdjustSupplementaryViewLayerZPosition: Bool = true
     private weak var collectionView: UICollectionView!
     private var reuseIdentifiers: Set<String> = []
@@ -77,12 +77,6 @@ open class CollectionDirector: NSObject {
 
     //todo: add/remove array of sections
 
-    public func performWithoutReloading(changes: (() -> Void)) {
-        disableUpdates = true
-        changes()
-        disableUpdates = false
-    }
-    
     public func reload() {
         collectionView.reloadData()
     }
@@ -204,7 +198,7 @@ extension CollectionDirector : UICollectionViewDelegateFlowLayout {
 
     open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
         let item = sections[indexPath.section].item(for: indexPath.row)
-        return item.estimatedSize
+        return item.estimatedSize(collectionViewSize: collectionView.bounds.size)
     }
 
     open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
@@ -213,13 +207,13 @@ extension CollectionDirector : UICollectionViewDelegateFlowLayout {
 
     open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
         let section_ = sections[section]
-        let value = section_.headerItem?.estimatedSize ?? .zero
+        let value = section_.headerItem?.estimatedSize(collectionViewSize: collectionView.bounds.size) ?? .zero
         return value
     }
 
     open func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
         let section_ = sections[section]        
-        let value = section_.footerItem?.estimatedSize ?? .zero
+        let value = section_.footerItem?.estimatedSize(collectionViewSize: collectionView.bounds.size) ?? .zero
         return value
     }
 

CollectionKit/CollectionItem.swift

@@ -18,11 +18,15 @@ open class CollectionItem<CellType: ConfigurableCollectionItem>: AbstractCollect
     open var onUnighlight: ((_ indexPath: IndexPath) -> Void)?
     open var shouldHighlight: Bool?
 
-    open var estimatedSize: CGSize { return CellType.estimatedSize(item: self.item) }
     open var item: CellType.T
     open var reuseIdentifier: String { return CellType.reuseIdentifier }
+    
     public let identifier: String = UUID().uuidString
 
+    public func estimatedSize(collectionViewSize: CGSize) -> CGSize {
+        return CellType.estimatedSize(item: self.item, collectionViewSize: collectionViewSize)
+    }
+    
     public var cellType: AnyClass {
         return CellType.self
     }

CollectionKit/Helpers.swift

@@ -123,7 +123,7 @@ extension Array {
 //MARK:- ConfigurableCollectionItem
 public protocol ConfigurableCollectionItem : Reusable {
     associatedtype T
-    static func estimatedSize(item: T?) -> CGSize
+    static func estimatedSize(item: T?, collectionViewSize: CGSize) -> CGSize
     func configure(item: T)
 }
 
@@ -143,8 +143,9 @@ public protocol ActionableCollectionItem {
 //MARK:- AbstractCollectionItem
 public protocol AbstractCollectionItem : ActionableCollectionItem {
     var reuseIdentifier: String { get }
-    var estimatedSize: CGSize { get }
+//    var estimatedSize: CGSize { get }
     var identifier: String { get }
     var cellType: AnyClass { get }
     func configure(_: UICollectionReusableView)
+    func estimatedSize(collectionViewSize: CGSize) -> CGSize
 }

CollectionKit/ViewController.swift

@@ -18,9 +18,7 @@ class ViewController: UIViewController {
     override func viewDidLoad() {
         super.viewDidLoad()
         if #available(iOS 11.0, *) {
-//            navigationController?.navigationBar.prefersLargeTitles = true
-        } else {
-            // Fallback on earlier versions
+            navigationController?.navigationBar.prefersLargeTitles = true
         }
 
         collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: UICollectionViewFlowLayout())
@@ -30,12 +28,14 @@ class ViewController: UIViewController {
         collectionView.alwaysBounceVertical = true
         director = CollectionDirector(colletionView: collectionView)
         director.shouldUseAutomaticCellRegistration = true
+        collectionView.register(Header.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: Header.reuseIdentifier)
 //        collectionView.registerClass(CollectionCell.self)
 //        collectionView.registerNib(CellFromXIB.self)
         section = CollectionSection()
         section.minimumInterItemSpacing = 0.5
-        section.insetForSection = UIEdgeInsetsMake(20, 0, 20, 0)
+//        section.insetForSection = UIEdgeInsetsMake(20, 0, 20, 0)
         section.lineSpacing = 2
+        section.headerItem = CollectionItem<Header>(item: "title")
         for _ in 0..<3 {
             let row = CollectionItem<CollectionCell>(item: "text")
                 .onSelect({ (_) in

Examples/CellFromXIB.swift

@@ -14,8 +14,8 @@ final class CellFromXIB : UICollectionViewCell {
 }
 
 extension CellFromXIB : ConfigurableCollectionItem {
-    static func estimatedSize(item: String?) -> CGSize {
-        return CGSize(width: UIScreen.main.bounds.width - 40, height: 60)
+    static func estimatedSize(item: String?, collectionViewSize: CGSize) -> CGSize {
+        return CGSize(width: collectionViewSize.width - 40, height: 60)
     }
 
     func configure(item: String) {

Examples/Header.swift

@@ -0,0 +1,35 @@
+//
+//  Header.swift
+//  Examples
+//
+//  Created by Igor Vedeneev on 03.12.17.
+//  Copyright © 2017 Igor Vedeneev. All rights reserved.
+//
+
+import UIKit
+import CollectionKit
+
+final class Header: UICollectionReusableView {
+    let titleLabel = UILabel()
+    
+    override init(frame: CGRect) {
+        super.init(frame: frame)
+        titleLabel.font = UIFont.systemFont(ofSize: 12, weight: .light)
+        titleLabel.frame = CGRect(x: 20, y: 20, width: 100, height: 13)
+        addSubview(titleLabel)
+    }
+    
+    required init?(coder aDecoder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}
+
+extension Header : ConfigurableCollectionItem {
+    func configure(item: String) {
+        titleLabel.text = item.uppercased()
+    }
+    
+    static func estimatedSize(item: String?, collectionViewSize: CGSize) -> CGSize {
+        return CGSize(width: collectionViewSize.width, height: 48)
+    }
+}

README.md

@@ -7,11 +7,11 @@ Framework to manage complex `UICollectionView` in declarative way and very few l
  - [x] Type-safe generic cells
  - [x] No need to implement `UICollectionViewDataSource` and `UICollectionViewDelegate`
  - [x] Easy way to map your models into cells
- - [x] Updating without `performBatchUpdates` or whatever
+ - [x] Convinient updations
  - [x] Supports cells from code and xibs and storyboard
  - [x] Supports custom section imlementations
  - [x] Register cells and reusable views automatically
- - [x] Automatic cells and reusable views registration (if needed)
+ - [x] Fix scroll indicator clipping at iOS11 (https://stackoverflow.com/questions/46747960/ios11-uicollectionsectionheader-clipping-scroll-indicator)
 
 # Getting Started
 
@@ -43,8 +43,8 @@ director += section
 Cell must implement `ConfigurableCollectionCell` protocol. You need to specify cell size and configure methods:
 ```swift
 extension CollectionCell : ConfigurableCollectionItem {
-    static func estimatedSize(item: String?) -> CGSize {
-        return CGSize(width: UIScreen.main.bounds.width, height: 50)
+    static func estimatedSize(item: String, collectionViewSize: CGSize) -> CGSize {
+        return CGSize(width: collectionViewSize.width, height: 50)
     }
 
     func configure(item: String) {
@@ -74,20 +74,13 @@ section.lineSpacing = 2
 ```
 
 ## Updating
-You can update collection view only by operating with section and item objects without any `performBatchUpdates`:
+You can update collection view only by operating with section and item objects without any `IndexPath` mess: put usual operations in `performUpdates` block
 ```swift
-// insert item at specific position
-let row = CollectionItem<CollectionCell>(item: "hello")
-section.insert(item: row, at: 0)
-
-//append item to bottom of section
-section.append(item: row)
-
-//remove item at specific position
-section.remove(at: 0)
-
-//reload cell
-row.reload(with: "reloaded")
+self.director.performUpdates { [unowned self] in
+    self.section.append(item: row)
+    self.section.insert(item: row, at: 0)
+    self.section.remove(item: item)
+}
 ```
 
 ## Custom sections