/FloatingPanel

A clean and easy-to-use floating panel UI component for iOS

Primary LanguageSwiftMIT LicenseMIT

Build Status Version Carthage compatible Platform Swift 4.2

FloatingPanel

FloatingPanel is a simple and easy-to-use UI component for a new interface introduced in Apple Maps, Shortcuts and Stocks app. The new interface displays the related contents and utilities in parallel as a user wants.

Maps Stocks

Maps(Landscape)

Features

  • Simple container view controller
  • Fluid animation and gesture handling
  • Scroll view tracking
  • Common UI elements: Grabber handle, Backdrop and Surface rounding corners
  • 1~3 anchor positions(full, half, tip)
  • Layout customization for all trait environments(i.e. Landscape orientation support)
  • Behavior customization
  • Free from common issues of Auto Layout and gesture handling

Examples are here.

Requirements

FloatingPanel is written in Swift 4.2. Compatible with iOS 10.0+

Installation

CocoaPods

FloatingPanel is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod 'FloatingPanel'

Carthage

For Carthage, add the following to your Cartfile:

github "scenee/FloatingPanel"

Getting Started

import UIKit
import FloatingPanel

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    var fpc: FloatingPanelController!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Initialize a `FloatingPanelController` object.
        fpc = FloatingPanelController()

        // Assign self as the delegate of the controller.
        fpc.delegate = self // Optional

        // Set a content view controller.
        let contentVC = ContentViewController()
        fpc.set(contentViewController: contentVC)

        // Track a scroll view(or the siblings) in the content view controller.
        fpc.track(scrollView: contentVC.tableView)

        // Add and show the views managed by the `FloatingPanelController` object to self.view.
        fpc.addPanel(toParent: self)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        // Remove the views managed by the `FloatingPanelController` object from self.view.
        fpc.removePanelFromParent()
    }
    ...
}

Usage

Customize the layout of a floating panel with FloatingPanelLayout protocol

Change the initial position and height

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    ...
    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
        return MyFloatingPanelLayout()
    }
    ...
}

class MyFloatingPanelLayout: FloatingPanelLayout {
    public var initialPosition: FloatingPanelPosition {
        return .tip
    }

    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
        switch position {
            case .full: return 16.0 // A top inset from safe area
            case .half: return 216.0 // A bottom inset from the safe area
            case .tip: return 44.0 // A bottom inset from the safe area
        }
    }
}

Support your landscape layout

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    ...
    func floatingPanel(_ vc: FloatingPanelController, layoutFor newCollection: UITraitCollection) -> FloatingPanelLayout? {
        return (newCollection.verticalSizeClass == .compact) ? FloatingPanelLandscapeLayout() : nil // Returning nil indicates to use the default layout
    }
    ...
}

class FloatingPanelLandscapeLayout: FloatingPanelLayout {
    public var initialPosition: FloatingPanelPosition {
        return .tip
    }
    public var supportedPositions: Set<FloatingPanelPosition> {
        return [.full, .tip]
    }

    public func insetFor(position: FloatingPanelPosition) -> CGFloat? {
        switch position {
            case .full: return 16.0
            case .tip: return 69.0
            default: return nil
        }
    }

    public func prepareLayout(surfaceView: UIView, in view: UIView) -> [NSLayoutConstraint] {
        return [
            surfaceView.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuid.leftAnchor, constant: 8.0),
            surfaceView.widthAnchor.constraint(equalToConstant: 291),
        ]
    }
}

Customize the behavior with FloatingPanelBehavior protocol

Modify your floating panel's interaction

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    ...
    func floatingPanel(_ vc: FloatingPanelController, behaviorFor newCollection: UITraitCollection) -> FloatingPanelBehavior? {
        return FloatingPanelStocksBehavior()
    }
    ...
}
...

class FloatingPanelStocksBehavior: FloatingPanelBehavior {
    var velocityThreshold: CGFloat {
        return 15.0
    }

    func interactionAnimator(_ fpc: FloatingPanelController, to targetPosition: FloatingPanelPosition, with velocity: CGVector) -> UIViewPropertyAnimator {
        let damping = self.damping(with: velocity)
        let springTiming = UISpringTimingParameters(dampingRatio: damping, initialVelocity: velocity)
        return UIViewPropertyAnimator(duration: 0.5, timingParameters: springTiming)
    }
    ...
}

Create an additional floating panel for a detail

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    var searchPanelVC: FloatingPanelController!
    var detailPanelVC: FloatingPanelController!

    override func viewDidLoad() {
        // Setup Search panel
        self.searchPanelVC = FloatingPanelController()

        let searchVC = SearchViewController()
        self.searchPanelVC.set(contentViewController: searchVC)
        self.searchPanelVC.track(scrollView: contentVC.tableView)

        self.searchPanelVC.addPanel(toParent: self)

        // Setup Detail panel
        self.detailPanelVC = FloatingPanelController()

        let contentVC = ContentViewController()
        self.detailPanelVC.set(contentViewController: contentVC)
        self.detailPanelVC.track(scrollView: contentVC.scrollView)

        self.detailPanelVC.addPanel(toParent: self)
    }
    ...
}

Move a position with an animation

In the following example, I move a floating panel to full or half position while opening or closing a search bar like Apple Maps.

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        ...
        fpc.move(to: .half, animated: true)
    }

    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
        ...
        fpc.move(to: .full, animated: true)
    }

Make your contents correspond with a floating panel behavior

class ViewController: UIViewController, FloatingPanelControllerDelegate {
    ...
    func floatingPanelWillBeginDragging(_ vc: FloatingPanelController) {
        if vc.position == .full {
            searchVC.searchBar.showsCancelButton = false
            searchVC.searchBar.resignFirstResponder()
        }
    }

    func floatingPanelDidEndDragging(_ vc: FloatingPanelController, withVelocity velocity: CGPoint, targetPosition: FloatingPanelPosition) {
        if targetPosition != .full {
            searchVC.hideHeader()
        }
    }
    ...
}

Notes

'Show' or 'Show Detail' Segues from FloatingPanelController's content view controller

'Show' or 'Show Detail' segues from a content view controller will be managed by a view controller(hereinafter called 'master VC') adding a floating panel. Because a floating panel is just a subview of the master VC.

FloatingPanelController has no way to manage a stack of view controllers like UINavigationController. If so, it would be so complicated and the interface will become UINavigationController. This component should not have the responsibility to manage the stack.

By the way, a content view controller can present a view controller modally with present(_:animated:completion:) or 'Present Modally' segue.

However, sometimes you want to show a destination view controller of 'Show' or 'Show Detail' segue with another floating panel. It's possible to override show(_:sender) of the master VC!

Here is an example.

class ViewController: UIViewController {
    var fpc: FloatingPanelController!
    var secondFpc: FloatingPanelController!

    ...
    override func show(_ vc: UIViewController, sender: Any?) {
        secondFpc = FloatingPanelController()

        secondFpc.set(contentViewController: vc)

        secondFpc.addPanel(toParent: self)
    }
    ...
}

A FloatingPanelController object proxies an action for show(_:sender) to the master VC. That's why the master VC can handle a destination view controller of a 'Show' or 'Show Detail' segue and you can hook show(_:sender) to show a secondally floating panel set the destination view controller to the content.

It's a greate way to decouple between a floating panel and the content VC.

FloatingPanelSurfaceView's issue on iOS 10

  • On iOS 10, FloatingPanelSurfaceView.cornerRadius isn't not automatically masked with the top rounded corners because of UIVisualEffectView issue. See https://forums.developer.apple.com/thread/50854. So you need to draw top rounding corners of your content. Here is an example in Examples/Maps.
override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    if #available(iOS 10, *) {
        visualEffectView.layer.cornerRadius = 9.0
        visualEffectView.clipsToBounds = true
    }
}
  • If you sets clear color to FloatingPanelSurfaceView.backgroundColor, please note the bottom overflow of your content on bouncing at full position. To prevent it, you need to expand your content. For example, See Example/Maps's Auto Layout settings of UIVisualEffectView in Main.storyborad.

Author

Shin Yamamoto shin@scenee.com

License

FloatingPanel is available under the MIT license. See the LICENSE file for more info.