Dynamic item size, disable pinning

CustomCollectionLayout/CollectionViewController.swift

@@ -70,6 +70,22 @@ extension CollectionViewController: UICollectionViewDataSource {
 
 }
 
+extension CollectionViewController: CustomCollectionViewLayoutDelegate {
+
+    func collectionView(_ collectionView: UICollectionView, widthOfColumn column: Int) -> CGFloat {
+        return 90
+    }
+
+    func collectionView(_ collectionView: UICollectionView, heightOfSection section: Int) -> CGFloat {
+        return 48
+    }
+
+    func numberOfColumns(in collectionView: UICollectionView) -> Int {
+        return 8
+    }
+
+}
+
 // MARK: - UICollectionViewDelegate
 extension CollectionViewController: UICollectionViewDelegate {
 

CustomCollectionLayout/CustomCollectionViewLayout.swift

@@ -8,15 +8,24 @@
 
 import UIKit
 
+protocol CustomCollectionViewLayoutDelegate: class {
+    func collectionView(_ collectionView: UICollectionView, widthOfColumn column: Int) -> CGFloat
+    func collectionView(_ collectionView: UICollectionView, heightOfSection section: Int) -> CGFloat
+}
+
 class CustomCollectionViewLayout: UICollectionViewLayout {
 
-    let numberOfColumns = 8
+    var numberOfColumns = 0
     var shouldPinFirstColumn = true
     var shouldPinFirstRow = true
 
     var itemAttributes = [[UICollectionViewLayoutAttributes]]()
     var itemsSize = [CGSize]()
     var contentSize: CGSize = .zero
+
+    weak var delegate: CustomCollectionViewLayoutDelegate? {
+        return collectionView?.delegate as? CustomCollectionViewLayoutDelegate
+    }
 
     override func prepare() {
         guard let collectionView = collectionView else {
@@ -27,25 +36,28 @@ class CustomCollectionViewLayout: UICollectionViewLayout {
             return
         }
 
+        numberOfColumns = collectionView.numberOfItems(inSection: 0)
+
         if itemAttributes.count != collectionView.numberOfSections {
             generateItemAttributes(collectionView: collectionView)
             return
         }
-
+        
         for section in 0..<collectionView.numberOfSections {
+
             for item in 0..<collectionView.numberOfItems(inSection: section) {
                 if section != 0 && item != 0 {
                     continue
                 }
 
                 let attributes = layoutAttributesForItem(at: IndexPath(item: item, section: section))!
-                if section == 0 {
+                if shouldPinFirstRow && section == 0 {
                     var frame = attributes.frame
                     frame.origin.y = collectionView.contentOffset.y
                     attributes.frame = frame
                 }
 
-                if item == 0 {
+                if shouldPinFirstColumn && item == 0 {
                     var frame = attributes.frame
                     frame.origin.x = collectionView.contentOffset.x
                     attributes.frame = frame
@@ -86,10 +98,7 @@ class CustomCollectionViewLayout: UICollectionViewLayout {
 extension CustomCollectionViewLayout {
 
     func generateItemAttributes(collectionView: UICollectionView) {
-        if itemsSize.count != numberOfColumns {
-            calculateItemSizes()
-        }
-
+
         var column = 0
         var xOffset: CGFloat = 0
         var yOffset: CGFloat = 0
@@ -101,7 +110,7 @@ extension CustomCollectionViewLayout {
             var sectionAttributes: [UICollectionViewLayoutAttributes] = []
 
             for index in 0..<numberOfColumns {
-                let itemSize = itemsSize[index]
+                let itemSize = sizeForItem(column: index, section: section)
                 let indexPath = IndexPath(item: index, section: section)
                 let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)
                 attributes.frame = CGRect(x: xOffset, y: yOffset, width: itemSize.width, height: itemSize.height).integral
@@ -149,28 +158,10 @@ extension CustomCollectionViewLayout {
         }
     }
 
-    func calculateItemSizes() {
-        itemsSize = []
-
-        for index in 0..<numberOfColumns {
-            itemsSize.append(sizeForItemWithColumnIndex(index))
-        }
-    }
-
-    func sizeForItemWithColumnIndex(_ columnIndex: Int) -> CGSize {
-        var text: NSString
-
-        switch columnIndex {
-        case 0:
-            text = "MMM-99"
-
-        default:
-            text = "Content"
-        }
-
-        let size: CGSize = text.size(attributes: [NSFontAttributeName: UIFont.systemFont(ofSize: 14.0)])
-        let width: CGFloat = size.width + 16
-        return CGSize(width: width, height: 30)
+    func sizeForItem(column: Int, section: Int) -> CGSize {
+        let width = delegate?.collectionView(collectionView!, widthOfColumn: column) ?? 0
+        let height = delegate?.collectionView(collectionView!, heightOfSection: section) ?? 0
+        return CGSize(width: width, height: height)
     }
 
 }

CustomCollectionLayout/Info.plist

@@ -31,6 +31,8 @@
 	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
 	</array>
 </dict>
 </plist>