[Issue 22] Fix bottom sheet height for navigation and table controllers (#27)

* Rename files

* Randomize test execution order

* New layout properties

* Use and test new layout height properties

* Add sizing for navigation controller and table views

* Don’t layout subviews when appearance changes

* Fix bug with clipped corners

Author: Mark Pospesel

.swiftpm/xcode/xcshareddata/xcschemes/YBottomSheet.xcscheme

@@ -58,7 +58,8 @@
       codeCoverageEnabled = "YES">
       <Testables>
          <TestableReference
-            skipped = "NO">
+            skipped = "NO"
+            testExecutionOrdering = "random">
             <BuildableReference
                BuildableIdentifier = "primary"
                BlueprintIdentifier = "YBottomSheetTests"

Sources/YBottomSheet/Animation/BottomSheetPresentAnimator.swift

@@ -28,6 +28,9 @@ class BottomSheetPresentAnimator: BottomSheetAnimator {
             var sheetFrame = sheet.sheetView.frame
             sheetFrame.origin.y = toFinalFrame.maxY + (sheet.appearance.elevation?.extent.top ?? 0)
             sheet.sheetView.frame = sheetFrame
+            // lay out sheet's subviews prior to first appearance
+            sheet.sheetView.layoutIfNeeded()
+            sheet.updateShadow()
             sheet.view.setNeedsLayout()
         }
 

Sources/YBottomSheet/BottomSheetController+Appearance+Layout.swift

@@ -0,0 +1,65 @@
+//
+//  BottomSheetController+Appearance+Layout.swift
+//  YBottomSheet
+//
+//  Created by Dev Karan on 19/01/23.
+//  Copyright © 2023 Y Media Labs. All rights reserved.
+//
+
+import UIKit
+
+extension BottomSheetController.Appearance {
+    /// A collection of layout properties for the `BottomSheetController`.
+    public struct Layout: Equatable {
+        /// Corner radius of bottom sheet view. Default is `16`.
+        public var cornerRadius: CGFloat
+
+        /// Minimum top offset of sheet from safe area top. Default is `44`.
+        ///
+        /// The top of the sheet will not move beyond this gap from the top of the safe area.
+        public var minimumTopOffset: CGFloat
+
+        /// Maximum content height of sheet.
+        ///
+        /// Only applicable for resizable sheets.
+        /// If `nil` a resizable sheet will be allowed to grow until it nearly fills the screen.
+        /// c.f. `minimumTopOffset`
+        public var maximumContentHeight: CGFloat?
+
+        /// Ideal content height of sheet.
+        ///
+        /// Used to determine the initial size of the sheet.
+        /// If `nil`, the content's `instrinsicContentHeight` will be used.
+        public var idealContentHeight: CGFloat?
+
+        /// Minimum content height of sheet.
+        ///
+        /// Only applicable for resizable sheets.
+        /// A resizable sheet will not be allowed to shrink its content below this value.
+        public var minimumContentHeight: CGFloat
+
+        /// Default layout.
+        public static let `default` = Layout()
+
+        // Initializes a bottom sheet layout.
+        /// - Parameters:
+        ///   - cornerRadius: corner radius of bottom sheet view. Default is `16`.
+        ///   - minimumTopOffset: minimum top offset. Default is `44`.
+        ///   - maximumContentHeight: maximum content height of sheet. Default is `nil`.
+        ///   - idealContentHeight: ideal content height of sheet. Default is `nil`.
+        ///   - minimumContentHeight: minimum content height of sheet. Default is `88`.
+        public init(
+            cornerRadius: CGFloat = 16,
+            minimumTopOffset: CGFloat = 44,
+            maximumContentHeight: CGFloat? = nil,
+            idealContentHeight: CGFloat? = nil,
+            minimumContentHeight: CGFloat = 88
+        ) {
+            self.cornerRadius = cornerRadius
+            self.minimumTopOffset = minimumTopOffset
+            self.maximumContentHeight = maximumContentHeight
+            self.idealContentHeight = idealContentHeight
+            self.minimumContentHeight = minimumContentHeight
+        }
+    }
+}

Sources/YBottomSheet/BottomSheetController+Appearance.swift

@@ -28,14 +28,6 @@ extension BottomSheetController {
         public var presentAnimationCurve: UIView.AnimationOptions
         /// Animation type during dismissing. Default is `curveEaseOut`.
         public var dismissAnimationCurve: UIView.AnimationOptions
-        /// Minimum top offset of sheet from safe area top. Default is `44`.
-        ///
-        /// The top of the sheet will not move beyond this gap from the top of the safe area.
-        public var minimumTopOffset: CGFloat
-        /// (Optional) Minimum content view height. Default is `nil`.
-        ///
-        /// Only applicable for resizable sheets. `nil` means to use the content view's intrinsic height as the minimum.
-        public var minimumContentHeight: CGFloat?
         /// Whether the sheet can be dismissed by swiping down or tapping on the dimmer. Default is `true`.
         ///
         /// The user can always dismiss the sheet from the close button if it is visible.
@@ -56,8 +48,6 @@ extension BottomSheetController {
         ///   - animationDuration: animation duration for bottom sheet. Default is `0.3`.
         ///   - presentAnimationCurve: animation type during presenting.
         ///   - dismissAnimationCurve: animation type during dismiss.
-        ///   - minimumTopOffset: minimum top offset. Default is `44`
-        ///   - minimumContentHeight: (optional) minimum content view height.
         ///   - isDismissAllowed: whether the sheet can be dismissed by swiping down or tapping on the dimmer.
         public init(
             indicatorAppearance: DragIndicatorView.Appearance? = nil,
@@ -68,8 +58,6 @@ extension BottomSheetController {
             animationDuration: TimeInterval = 0.3,
             presentAnimationCurve: UIView.AnimationOptions = .curveEaseIn,
             dismissAnimationCurve: UIView.AnimationOptions = .curveEaseOut,
-            minimumTopOffset: CGFloat = 44,
-            minimumContentHeight: CGFloat? = nil,
             isDismissAllowed: Bool = true
         ) {
             self.indicatorAppearance = indicatorAppearance
@@ -80,8 +68,6 @@ extension BottomSheetController {
             self.animationDuration = animationDuration
             self.presentAnimationCurve = presentAnimationCurve
             self.dismissAnimationCurve = dismissAnimationCurve
-            self.minimumTopOffset = minimumTopOffset
-            self.minimumContentHeight = minimumContentHeight
             self.isDismissAllowed = isDismissAllowed
         }
     }

Sources/YBottomSheet/BottomSheetController+build.swift

@@ -27,7 +27,7 @@ private extension BottomSheetController {
         if let backgroundColor = subview.backgroundColor,
            backgroundColor.rgbaComponents.alpha == 1 {
             // use the subview's background color for the sheet
-            sheetView.backgroundColor = backgroundColor
+            sheetContainerView.backgroundColor = backgroundColor
             // but we have to set the subview's background to nil or else
             // it will overflow the sheet and not be cropped by the corner radius.
             subview.backgroundColor = nil
@@ -58,7 +58,8 @@ private extension BottomSheetController {
         view.addSubview(dimmerView)
         view.addSubview(dimmerTapView)
         view.addSubview(sheetView)
-        sheetView.addSubview(stackView)
+        sheetView.addSubview(sheetContainerView)
+        sheetContainerView.addSubview(stackView)
         stackView.addArrangedSubview(indicatorContainer)
         stackView.addArrangedSubview(headerView)
         stackView.addArrangedSubview(contentView)
@@ -68,13 +69,19 @@ private extension BottomSheetController {
         dimmerView.constrainEdges()
         dimmerTapView.constrainEdges(.notBottom)
         dimmerTapView.constrain(.bottomAnchor, to: sheetView.topAnchor)
+        sheetContainerView.constrainEdges()
 
         sheetView.constrainEdges(.notTop)
         minimumTopOffsetAnchor = sheetView.constrain(
             .topAnchor,
             to: view.safeAreaLayoutGuide.topAnchor,
             relatedBy: .greaterThanOrEqual
         )
+        minimumContentHeightAnchor = contentView.constrain(
+            .heightAnchor,
+            relatedBy: .greaterThanOrEqual,
+            constant: appearance.layout.minimumContentHeight
+        )
 
         indicatorView.constrain(.bottomAnchor, to: indicatorContainer.bottomAnchor)
         indicatorTopAnchor = indicatorView.constrain(
@@ -83,11 +90,9 @@ private extension BottomSheetController {
         )
         indicatorView.constrainCenter(.x)
 
-        stackView.constrain(.topAnchor, to: sheetView.topAnchor)
+        stackView.constrainEdges(.top)
         stackView.constrainEdges(.horizontal, to: view.safeAreaLayoutGuide)
-        stackView.constrainEdges(.bottom, to: view.safeAreaLayoutGuide, relatedBy: .greaterThanOrEqual)
-        stackView.constrainEdges(.bottom, to: view.safeAreaLayoutGuide, priority: Priorities.sheetContentHugging)
-
+        stackView.constrainEdges(.bottom, to: view.safeAreaLayoutGuide)
         contentView.constrainEdges(.horizontal)
         headerView.constrainEdges(.horizontal)
     }

Sources/YBottomSheet/BottomSheetController.Appearance+Layout.swift

@@ -12,22 +12,17 @@ import UIKit
 public class BottomSheetController: UIViewController {
     internal let content: Content
     private var shadowSize: CGSize = .zero
+
     internal var minimumTopOffsetAnchor: NSLayoutConstraint?
     private var topAnchor: NSLayoutConstraint?
     internal var indicatorTopAnchor: NSLayoutConstraint?
-    private var childHeightAnchor: NSLayoutConstraint?
+    private var maximumContentHeightAnchor: NSLayoutConstraint?
+    internal var idealContentHeightAnchor: NSLayoutConstraint?
+    internal var minimumContentHeightAnchor: NSLayoutConstraint?
+
     private var panGesture: UIPanGestureRecognizer?
     internal lazy var lastYOffset: CGFloat = { sheetView.frame.origin.y }()
 
-    /// Absolute minimum height of sheet content
-    ///
-    /// Only used when `appearance.minimumContentHeight == nil`.
-    public var minimumContentHeight: CGFloat = 88 {
-        didSet {
-            updateChildView()
-        }
-    }
-
     /// Minimum downward velocity beyond which we interpret a pan gesture as a downward swipe.
     public var dismissThresholdVelocity: CGFloat = 1000
 
@@ -42,9 +37,12 @@ public class BottomSheetController: UIViewController {
     /// Dimmer view.
     let dimmerView = UIView()
     /// Bottom sheet view.
-    let sheetView: UIView = {
+    let sheetView = UIView()
+    /// Bottom sheet container view.
+    let sheetContainerView: UIView = {
         let view = UIView()
         view.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner]
+        view.clipsToBounds = true
         view.backgroundColor = .systemBackground
         return view
     }()
@@ -55,11 +53,7 @@ public class BottomSheetController: UIViewController {
     /// Bottom sheet header view.
     public internal(set) var headerView: SheetHeaderView!
     /// Holds the sheet's child content (view or view controller).
-    let contentView: UIView = {
-        let view = UIView()
-        view.clipsToBounds = true
-        return view
-    }()
+    let contentView = UIView()
 
     /// Comprises the indicator view, the header view, and the content view.
     let stackView: UIStackView = {
@@ -150,7 +144,7 @@ public class BottomSheetController: UIViewController {
 
         guard shadowSize != sheetView.bounds.size else { return }
         updateShadow()
-        shadowSize = contentView.bounds.size
+        shadowSize = sheetView.bounds.size
     }
 
     /// Performing the accessibility escape gesture dismisses the bottom sheet.
@@ -172,14 +166,13 @@ public class BottomSheetController: UIViewController {
 internal extension BottomSheetController {
     func updateViewAppearance() {
         dimmerTapView.isAccessibilityElement = appearance.isDismissAllowed
-        sheetView.layer.cornerRadius = appearance.layout.cornerRadius
-        minimumTopOffsetAnchor?.constant = appearance.minimumTopOffset
+        sheetContainerView.layer.cornerRadius = appearance.layout.cornerRadius
+        minimumTopOffsetAnchor?.constant = appearance.layout.minimumTopOffset
         updateShadow()
         dimmerView.backgroundColor = appearance.dimmerColor
         updateIndicatorView()
         updateHeaderView()
         updateChildView()
-        view.layoutIfNeeded()
     }
 
     func addGestures() {
@@ -189,6 +182,19 @@ internal extension BottomSheetController {
         let tapGesture = UITapGestureRecognizer(target: self, action: #selector(onDimmerTap))
         dimmerTapView.addGestureRecognizer(tapGesture)
     }
+
+    var childContentSize: CGSize {
+        switch content {
+        case .view(_, let view):
+            return view.layoutSize
+        case .controller(let viewController):
+            return viewController.layoutSize
+        }
+    }
+
+    func updateShadow() {
+        appearance.elevation?.apply(layer: sheetView.layer, cornerRadius: appearance.layout.cornerRadius)
+    }
 }
 
 private extension BottomSheetController {
@@ -226,33 +232,44 @@ private extension BottomSheetController {
     func updateChildView() {
         guard let childView = contentView.subviews.first else { return }
 
-        let height: CGFloat
-        let priority: UILayoutPriority
-
-        if let minimum = appearance.minimumContentHeight {
-            // If a minimum is specified, we make the sheet relatively easy to compress
-            // and enforce that specified minimum.
-            height = minimum
-            priority = Priorities.sheetCompressionResistanceLow
+        // Enforce maximum height (if any)
+        if let maximum = appearance.layout.maximumContentHeight {
+            if let maximumContentHeightAnchor = maximumContentHeightAnchor {
+                maximumContentHeightAnchor.constant = maximum
+            } else {
+                maximumContentHeightAnchor = childView.constrain(
+                    .heightAnchor,
+                    relatedBy: .lessThanOrEqual,
+                    constant: maximum
+                )
+            }
         } else {
-            // If no minimumContentHeight is specified, we make the sheet difficult
-            // to compress beyond intrinsicContentSize.height and enforce an absolute minimum.
-            height = minimumContentHeight // absolute minimum
-            priority = Priorities.sheetCompressionResistanceHigh
+            maximumContentHeightAnchor?.isActive = false
         }
 
-        childView.setContentCompressionResistancePriority(priority, for: .vertical)
-        if let anchor = childHeightAnchor {
-            anchor.constant = height
+        // Enforce ideal height (if any)
+        // (otherwise sheet height defaults to childView.instrinsicContentSize.height)
+        let idealHeight = appearance.layout.idealContentHeight ?? childContentSize.height
+        if idealHeight > 0.0 {
+            if let idealContentHeightAnchor = idealContentHeightAnchor {
+                idealContentHeightAnchor.constant = idealHeight
+            } else {
+                idealContentHeightAnchor = childView.constrain(
+                    .heightAnchor,
+                    constant: idealHeight,
+                    priority: Priorities.idealContentSize
+                )
+            }
         } else {
-            childHeightAnchor = childView.constrain(.heightAnchor, relatedBy: .greaterThanOrEqual, constant: height)
+            idealContentHeightAnchor?.isActive = false
         }
+
+        // Enforce minimum height
+        minimumContentHeightAnchor?.constant = appearance.layout.minimumContentHeight
+
+        childView.setContentCompressionResistancePriority(Priorities.sheetCompressionResistance, for: .vertical)
     }
 
-    func updateShadow() {
-        appearance.elevation?.apply(layer: sheetView.layer)
-    }
-
     func onDismiss() {
         dismiss(animated: true)
     }

Sources/YBottomSheet/BottomSheetController.swift

@@ -1,5 +1,5 @@
 //
-//  DragIndicatorView.Appearance+Layout.swift
+//  DragIndicatorView+Appearance+Layout.swift
 //  YBottomSheet
 //
 //  Created by Dev Karan on 05/01/23.

Sources/YBottomSheet/DragIndicatorView/DragIndicatorView.Appearance+Layout.swift renamed to Sources/YBottomSheet/DragIndicatorView/DragIndicatorView+Appearance+Layout.swift

@@ -12,9 +12,8 @@ internal extension BottomSheetController {
     /// Priorities for various non-required constraints.
     enum Priorities {
         static let panGesture = UILayoutPriority(775)
-        static let sheetContentHugging = UILayoutPriority(751)
-        static let sheetCompressionResistanceLow = UILayoutPriority.defaultLow
-        static let sheetCompressionResistanceHigh = UILayoutPriority(800)
+        static let idealContentSize = UILayoutPriority(251)
+        static let sheetCompressionResistance = UILayoutPriority.defaultLow
     }
 
     /// Types of content that can populate a bottom sheet