Implement grid layout

Development/Development/BookCollectionView.swift

@@ -418,3 +418,41 @@ struct BookPlatformList: View, PreviewProvider {
 
   return Preview()
 }
+
+#Preview("Simple grid layout") {
+
+  struct Book: View {
+
+    @State var selected: Set<Item.ID> = .init()
+
+    var body: some View {
+
+      CollectionView(
+        layout: .grid,
+        content: {
+          SelectableForEach(
+            data: Item.mock(),
+            selection: .multiple(
+              selected: selected,
+              canSelectMore: selected.count < 3,
+              onChange: { e, action in
+                switch action {
+                case .selected:
+                  selected.insert(e)
+                case .deselected:
+                  selected.remove(e)
+                }
+              }
+            ),
+            selectionIdentifier: \.id,
+            cell: { index, item in
+              Cell(index: index, item: item)
+            }
+          )
+        }
+      )
+    }
+  }
+
+  return Book()
+}

Sources/CollectionView/CollectionViewLayout.swift

@@ -155,36 +155,73 @@ public enum CollectionViewLayouts {
   }
 
   public struct Grid: CollectionViewLayoutType {
+
+    public let gridItems: [GridItem]
 
-    public let columns: [GridItem]
-    public let spacing: CGFloat?
+    public let direction: CollectionViewListDirection
+
+    public var showsIndicators: Bool = false
+
     public var contentPadding: EdgeInsets
 
+    public var spacing: CGFloat?
+
     public init(
-      columns: [GridItem],
+      gridItems: [GridItem],
+      direction: CollectionViewListDirection,
       spacing: CGFloat? = nil,
       contentPadding: EdgeInsets = .init()
     ) {
-      self.columns = columns
+      self.direction = direction
+      self.contentPadding = contentPadding
+      self.gridItems = gridItems
       self.spacing = spacing
       self.contentPadding = contentPadding
     }
 
+    public consuming func contentPadding(_ contentPadding: EdgeInsets) -> Self {
+
+      self.contentPadding = contentPadding
+
+      return self
+    }
+
+    public consuming func showsIndicators(_ showsIndicators: Bool) -> Self {
+
+      self.showsIndicators = showsIndicators
+
+      return self
+    }
+
     public func body(content: Content) -> some View {
-      ScrollView {
-        LazyVGrid(columns: columns, spacing: spacing) {
-          content
+      switch direction {
+      case .vertical:
+
+        ScrollView(.vertical, showsIndicators: showsIndicators) {
+          LazyVGrid(
+            columns: gridItems,
+            spacing: spacing
+          ) {
+            content
+          }          
+          .padding(contentPadding)
         }
-        .padding(contentPadding)
+
+      case .horizontal:
+
+        ScrollView(.horizontal, showsIndicators: showsIndicators) {          
+          LazyHGrid(
+            rows: gridItems,
+            spacing: spacing
+          ) {
+            content
+          }
+          .padding(contentPadding)
+        }
+
       }
     }
 
-    public consuming func contentPadding(_ contentPadding: EdgeInsets) -> Self {
-
-      self.contentPadding = contentPadding
-
-      return self
-    }
   }
 
 }
@@ -202,10 +239,15 @@ extension CollectionViewLayoutType where Self == CollectionViewLayouts.List<Empt
 extension CollectionViewLayoutType where Self == CollectionViewLayouts.Grid {
 
   public static func grid(
-    columns: [GridItem],
+    gridItems: [GridItem],
+    direction: CollectionViewListDirection,
     spacing: CGFloat? = nil
   ) -> Self {
-    CollectionViewLayouts.Grid(columns: columns, spacing: spacing)
+    CollectionViewLayouts.Grid(
+      gridItems: gridItems,
+      direction: direction,
+      spacing: spacing
+    )
   }
 
 }