Add Expandable protocol and ExpandableCellHeightCalculator

Sources/ConfigurableCell.swift

@@ -25,10 +25,15 @@ public protocol ConfigurableCell {
     associatedtype CellData
 
     static var reuseIdentifier: String { get }
+
     static var estimatedHeight: CGFloat? { get }
+
     static var defaultHeight: CGFloat? { get }
 
+    static var layoutType: LayoutType { get }
+
     func configure(with _: CellData)
+
 }
 
 public extension ConfigurableCell where Self: UITableViewCell {
@@ -44,4 +49,9 @@ public extension ConfigurableCell where Self: UITableViewCell {
     static var defaultHeight: CGFloat? {
         return nil
     }
+
+    static var layoutType: LayoutType {
+        return .auto
+    }
+
 }

Sources/Expandable.swift

@@ -0,0 +1,70 @@
+import UIKit
+
+public protocol Expandable {
+
+    associatedtype ViewModelType: ExpandableCellViewModel
+
+    var viewModel: ViewModelType? { get }
+
+    func configureAppearance(isCollapsed: Bool)
+
+}
+
+extension Expandable where Self: UITableViewCell & ConfigurableCell {
+
+    public func initState() {
+        guard let viewModel = viewModel else {
+            return
+        }
+
+        changeState(isCollapsed: viewModel.isCollapsed)
+    }
+
+    private func changeState(isCollapsed: Bool) {
+        // layout to get right frames, frame of bottom subview can be used to get expanded height
+        layoutIfNeeded()
+
+        // apply changes
+        configureAppearance(isCollapsed: isCollapsed)
+        layoutIfNeeded()
+    }
+
+    public func toggleState(animated: Bool = true,
+                            animationDuration: TimeInterval = 0.3) {
+
+        guard let tableView = tableView,
+              let viewModel = viewModel else {
+            return
+        }
+
+        let contentOffset = tableView.contentOffset
+
+        if animated {
+            UIView.animate(withDuration: animationDuration,
+                           animations: { [weak self] in
+                self?.applyChanges(isCollapsed: !viewModel.isCollapsed)
+            }, completion: { _ in
+                viewModel.isCollapsed.toggle()
+            })
+        } else {
+            applyChanges(isCollapsed: !viewModel.isCollapsed)
+            viewModel.isCollapsed.toggle()
+        }
+
+        tableView.beginUpdates()
+        tableView.endUpdates()
+
+        tableView.setContentOffset(contentOffset, animated: false)
+    }
+
+    private func applyChanges(isCollapsed: Bool) {
+        changeState(isCollapsed: isCollapsed)
+
+        if let indexPath = indexPath,
+           let tableDirector = (tableView?.delegate as? TableDirector),
+           let cellHeightCalculator = tableDirector.rowHeightCalculator as? ExpandableCellHeightCalculator {
+            cellHeightCalculator.updateCached(height: height(layoutType: Self.layoutType), for: indexPath)
+        }
+    }
+
+}

Sources/ExpandableCellHeightCalculator.swift

@@ -0,0 +1,55 @@
+import UIKit
+
+public final class ExpandableCellHeightCalculator: RowHeightCalculator {
+
+    private weak var tableView: UITableView?
+
+    private var prototypes = [String: UITableViewCell]()
+
+    private var cachedHeights = [IndexPath: CGFloat]()
+
+    public init(tableView: UITableView?) {
+        self.tableView = tableView
+    }
+
+    public func updateCached(height: CGFloat, for indexPath: IndexPath) {
+        cachedHeights[indexPath] = height
+    }
+
+    public func height(forRow row: Row, at indexPath: IndexPath) -> CGFloat {
+
+        guard let tableView = tableView else {
+            return 0
+        }
+
+        if let height = cachedHeights[indexPath] {
+            return height
+        }
+
+        var prototypeCell = prototypes[row.reuseIdentifier]
+        if prototypeCell == nil {
+            prototypeCell = tableView.dequeueReusableCell(withIdentifier: row.reuseIdentifier)
+            prototypes[row.reuseIdentifier] = prototypeCell
+        }
+
+        guard let cell = prototypeCell else {
+            return 0
+        }
+
+        row.configure(cell)
+        cell.layoutIfNeeded()
+
+        let height = cell.height(layoutType: row.layoutType)
+        cachedHeights[indexPath] = height
+        return height
+    }
+
+    public func estimatedHeight(forRow row: Row, at indexPath: IndexPath) -> CGFloat {
+        return height(forRow: row, at: indexPath)
+    }
+
+    public func invalidate() {
+        cachedHeights.removeAll()
+    }
+
+}

Sources/ExpandableCellViewModel.swift

@@ -0,0 +1,5 @@
+public protocol ExpandableCellViewModel: class {
+
+    var isCollapsed: Bool { get set }
+
+}

Sources/LayoutType.swift

@@ -0,0 +1,7 @@
+public enum LayoutType {
+
+    case manual
+
+    case auto
+
+}

Sources/TableKit.swift

@@ -33,6 +33,7 @@ public struct TableKitUserInfoKeys {
 public protocol RowConfigurable {
 
     func configure(_ cell: UITableViewCell)
+
 }
 
 public protocol RowActionable {
@@ -58,7 +59,8 @@ public protocol Row: RowConfigurable, RowActionable, RowHashable {
 
     var reuseIdentifier: String { get }
     var cellType: AnyClass { get }
-
+
+    var layoutType: LayoutType { get }
     var estimatedHeight: CGFloat? { get }
     var defaultHeight: CGFloat? { get }
 }

Sources/TableRow.swift

@@ -41,6 +41,10 @@ open class TableRow<CellType: ConfigurableCell>: Row where CellType: UITableView
     open var defaultHeight: CGFloat? {
         return CellType.defaultHeight
     }
+
+    open var layoutType: LayoutType {
+        return CellType.layoutType
+    }
 
     open var cellType: AnyClass {
         return CellType.self
@@ -59,7 +63,7 @@ open class TableRow<CellType: ConfigurableCell>: Row where CellType: UITableView
 
         (cell as? CellType)?.configure(with: item)
     }
-    
+
     // MARK: - RowActionable -
 
     open func invoke(action: TableRowActionType, cell: UITableViewCell?, path: IndexPath, userInfo: [AnyHashable: Any]? = nil) -> Any? {

Sources/UITableViewCell+Extensions.swift

@@ -0,0 +1,32 @@
+import UIKit
+
+extension UITableViewCell {
+
+    var tableView: UITableView? {
+        var view = superview
+
+        while view != nil && !(view is UITableView) {
+            view = view?.superview
+        }
+
+        return view as? UITableView
+    }
+
+    var indexPath: IndexPath? {
+        guard let indexPath = tableView?.indexPath(for: self) else {
+            return nil
+        }
+
+        return indexPath
+    }
+
+    public func height(layoutType: LayoutType) -> CGFloat {
+        switch layoutType {
+        case .auto:
+            return contentView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize).height
+        case .manual:
+            return contentView.subviews.map { $0.frame.maxY }.max() ?? 0
+        }
+    }
+
+}

TableKit.xcodeproj/project.pbxproj

@@ -7,6 +7,11 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		3201E78421BE9DE1001DF9E7 /* ExpandableCellHeightCalculator.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3201E78321BE9DE1001DF9E7 /* ExpandableCellHeightCalculator.swift */; };
+		3201E78621BE9E25001DF9E7 /* UITableViewCell+Extensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3201E78521BE9E25001DF9E7 /* UITableViewCell+Extensions.swift */; };
+		3201E78821BE9EB2001DF9E7 /* Expandable.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3201E78721BE9EB2001DF9E7 /* Expandable.swift */; };
+		3201E78A21BE9ED4001DF9E7 /* ExpandableCellViewModel.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3201E78921BE9ED4001DF9E7 /* ExpandableCellViewModel.swift */; };
+		32BDFE9F21C167F400D0BBB4 /* LayoutType.swift in Sources */ = {isa = PBXBuildFile; fileRef = 32BDFE9E21C167F400D0BBB4 /* LayoutType.swift */; };
 		50CF6E6B1D6704FE004746FF /* TableCellRegisterer.swift in Sources */ = {isa = PBXBuildFile; fileRef = 50CF6E6A1D6704FE004746FF /* TableCellRegisterer.swift */; };
 		50E858581DB153F500A9AA55 /* TableKit.swift in Sources */ = {isa = PBXBuildFile; fileRef = 50E858571DB153F500A9AA55 /* TableKit.swift */; };
 		DA9EA7AF1D0EC2C90021F650 /* ConfigurableCell.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA9EA7A61D0EC2C90021F650 /* ConfigurableCell.swift */; };
@@ -32,6 +37,11 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		3201E78321BE9DE1001DF9E7 /* ExpandableCellHeightCalculator.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ExpandableCellHeightCalculator.swift; sourceTree = "<group>"; };
+		3201E78521BE9E25001DF9E7 /* UITableViewCell+Extensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UITableViewCell+Extensions.swift"; sourceTree = "<group>"; };
+		3201E78721BE9EB2001DF9E7 /* Expandable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Expandable.swift; sourceTree = "<group>"; };
+		3201E78921BE9ED4001DF9E7 /* ExpandableCellViewModel.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ExpandableCellViewModel.swift; sourceTree = "<group>"; };
+		32BDFE9E21C167F400D0BBB4 /* LayoutType.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LayoutType.swift; sourceTree = "<group>"; };
 		50CF6E6A1D6704FE004746FF /* TableCellRegisterer.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TableCellRegisterer.swift; sourceTree = "<group>"; };
 		50E858571DB153F500A9AA55 /* TableKit.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TableKit.swift; sourceTree = "<group>"; };
 		DA9EA7561D0B679A0021F650 /* TableKit.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = TableKit.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -90,16 +100,21 @@
 		DA9EA7A51D0EC2B90021F650 /* Sources */ = {
 			isa = PBXGroup;
 			children = (
-				50E858571DB153F500A9AA55 /* TableKit.swift */,
-				DA9EA7AA1D0EC2C90021F650 /* TableDirector.swift */,
+				DA9EA7A61D0EC2C90021F650 /* ConfigurableCell.swift */,
+				3201E78321BE9DE1001DF9E7 /* ExpandableCellHeightCalculator.swift */,
+				DA9EA7A81D0EC2C90021F650 /* Operators.swift */,
+				DA9EA7A91D0EC2C90021F650 /* TableCellAction.swift */,
 				50CF6E6A1D6704FE004746FF /* TableCellRegisterer.swift */,
+				DA9EA7AA1D0EC2C90021F650 /* TableDirector.swift */,
+				50E858571DB153F500A9AA55 /* TableKit.swift */,
+				DA9EA7A71D0EC2C90021F650 /* TablePrototypeCellHeightCalculator.swift */,
 				DA9EA7AB1D0EC2C90021F650 /* TableRow.swift */,
 				DA9EA7AC1D0EC2C90021F650 /* TableRowAction.swift */,
 				DA9EA7AE1D0EC2C90021F650 /* TableSection.swift */,
-				DA9EA7A91D0EC2C90021F650 /* TableCellAction.swift */,
-				DA9EA7A71D0EC2C90021F650 /* TablePrototypeCellHeightCalculator.swift */,
-				DA9EA7A61D0EC2C90021F650 /* ConfigurableCell.swift */,
-				DA9EA7A81D0EC2C90021F650 /* Operators.swift */,
+				3201E78521BE9E25001DF9E7 /* UITableViewCell+Extensions.swift */,
+				3201E78721BE9EB2001DF9E7 /* Expandable.swift */,
+				3201E78921BE9ED4001DF9E7 /* ExpandableCellViewModel.swift */,
+				32BDFE9E21C167F400D0BBB4 /* LayoutType.swift */,
 			);
 			path = Sources;
 			sourceTree = "<group>";
@@ -231,13 +246,18 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				3201E78A21BE9ED4001DF9E7 /* ExpandableCellViewModel.swift in Sources */,
 				50CF6E6B1D6704FE004746FF /* TableCellRegisterer.swift in Sources */,
 				DA9EA7AF1D0EC2C90021F650 /* ConfigurableCell.swift in Sources */,
 				DA9EA7B31D0EC2C90021F650 /* TableDirector.swift in Sources */,
+				3201E78821BE9EB2001DF9E7 /* Expandable.swift in Sources */,
 				DA9EA7B71D0EC2C90021F650 /* TableSection.swift in Sources */,
 				DA9EA7B01D0EC2C90021F650 /* TablePrototypeCellHeightCalculator.swift in Sources */,
+				3201E78421BE9DE1001DF9E7 /* ExpandableCellHeightCalculator.swift in Sources */,
 				DA9EA7B51D0EC2C90021F650 /* TableRowAction.swift in Sources */,
 				DA9EA7B21D0EC2C90021F650 /* TableCellAction.swift in Sources */,
+				32BDFE9F21C167F400D0BBB4 /* LayoutType.swift in Sources */,
+				3201E78621BE9E25001DF9E7 /* UITableViewCell+Extensions.swift in Sources */,
 				DA9EA7B11D0EC2C90021F650 /* Operators.swift in Sources */,
 				DA9EA7B41D0EC2C90021F650 /* TableRow.swift in Sources */,
 				50E858581DB153F500A9AA55 /* TableKit.swift in Sources */,