A configurable framework for presenting bottom sheets on iOS.

• Features
• Requirements
• Installation
  • Swift Package Manager
  • CocoaPods
  • Carthage
• Usage
  • Overview
  • Configuration
  • Scroll View Interaction
  • Pushing/Popping Sheets
• Examples
• License

• Sheets can be presented in different sizes:
  • Full screen sheets are similar to UIModalPresentationPageSheet on iOS 13+.
  • Half screen sheets.
  • Fitting size sheets are sized to the content displayed, when smaller than a full screen sheet.
• Content in the sheet can be embedded in a scroll view to support scrolling when the content height exceeds that of the sheet.
• Supports sliding the sheet between different positions and swiping to dismiss.
• Sheets can be stacked - push additional sheets on and then pop them off.
• Automatically adjusts the sheet when the keyboard appears/disappears.
• Configure display properties like the top inset of a full-screen sheet, optional handle to indicate sheet sliding, dimmed background view and more.

Full Sheet	Half Sheet	Fitting Size Sheet	Fitting Size with a Keyboard

• iOS 11+

Add .package(url: "https://github.com/livefront/Duvet.git", exact: "0.0.7") to your Package.swift file dependencies.

Add pod Duvet to your Podfile.

Add github livefront/Duvet to your Cartfile.

1. Import Duvet into the file that you will present a sheet from.

   import Duvet

2. Create a SheetItem with the view controller that should will be shown in the sheet.

   let sheetItem = SheetItem(
       viewController: viewController,
       configuration: SheetConfiguration(),
       // See Scroll View Interaction below for an example with a scroll view.
       scrollView: nil
   )

3. Create a SheetViewController. The SheetViewController is a container view controller for a stack of sheets, similar to UINavigationController. It will allow you to push on and pop off additional SheetItems.

   let sheetViewController = SheetViewController(sheetItem: sheetItem)
   sheetViewController.modalPresentationStyle = .custom
   
   // Note: `sheetTransitioningDelegate` needs to be retained by the presenting
   // view controller since `sheetViewController` only keeps a weak reference.
   let sheetTransitioningDelegate = SheetTransitioningDelegate()
   sheetViewController.transitioningDelegate = sheetTransitioningDelegate

4. Conform the presenting view controller to SheetViewControllerDelegate to handle dismissing the sheet.

   extension PresentingViewController: SheetViewControllerDelegate {
       func dismissSheetViewController() {
           dismiss(animated: true, completion: nil)
       }
   }

5. Then the SheetViewController can be presented by your presenting view controller.

   <presentingViewController>.present(sheetViewController, animated: true)

Various parameters can be configured for a sheet via a SheetConfiguration when creating a SheetItem.

If the view controller that you want to show in the sheet has a scroll view that wraps the sheet content, Duvet needs to be able to interact with it so that it knows whether you should be scrolling the scroll view or sliding the sheet.

For this interaction to occur, pass a reference to your view controller's scroll view when creating the SheetItem:

let sheetItem = SheetItem(
    viewController: viewController,
    configuration: SheetConfiguration(),
    scrollView: viewController.scrollView
)

Duvet will make the following changes to the scroll view:

• Duvet will become the UIScrollView delegate. If there was an existing delegate on the scroll view, Duvet will continue forwarding any UIScrollViewDelegate methods to the original delegate. It's important to set a delegate, if necessary, before creating the SheetItem to continue receiving UIScrollViewDelegate methods.
• Enables alwaysBounceVertical. This is required for sliding the sheet or swipe to dismiss.
• The sheet view will also add itself as a target of the scroll view's panGestureRecognizer.

SheetViewController supports managing a stack of SheetItems. This allows additional sheets to be pushed on and then popped off of the stack.

1. Display an initial sheet.

   let sheetItem = SheetItem(
       viewController: <view controller for the first sheet>
       configuration: SheetConfiguration(),
       scrollView: nil
   )
   let sheetViewController = SheetViewController(sheetItem: sheetItem)
   sheetViewController.delegate = self
   sheetViewController.modalPresentationStyle = .custom
   sheetViewController.transitioningDelegate = sheetTransitioningDelegate
   present(sheetViewController, animated: true)

2. Push an additional sheet onto the sheet stack.

   let sheetItem2 = SheetItem(
       viewController: <view controller for the second sheet>
       configuration: SheetConfiguration(),
       scrollView: nil
   )
   sheetViewController.push(sheetItem: sheetItem2, animated: true)

3. Pop that sheet off of the sheet stack.

   sheetViewController.pop(animated: true)

There is an example application showing how to present and configure Duvet for many common use cases in the Example directory.

This library is released under the Apache 2.0 license. See the LICENSE file for details.