SwiftyCam capture session is not running

Question

I have created my camera view following the demo project on GitHub from SwiftyCam Everything lays out correctly and is going well; however, when the camera button is pushed I get a message in the console saying "[SwiftyCam]: Cannot take photo. Capture session is not running". There have been other people having this problem with swift 4 and you can find that here. I have gone through the whole framework line by line but for some reason I can't figure it out. I would really appreciate it if someone could look at the framework and the documentation and help me out. The way I'm doing it is just about exactly how it's done in the Swift 4 demo project so that would be the code reference.

Thank you in advance

EDIT: Below is the code when setting up the SwipeNavigationController after the WelcomeVC

let swipeNavigationController = SwipeNavigationController(centerViewController: CameraViewController())

    swipeNavigationController.topViewController = BlueView()
    swipeNavigationController.bottomViewController = PinkView()
    swipeNavigationController.leftViewController = OrangeView()
    swipeNavigationController.rightViewController = GreenView()



    cameraView.navigationController?.setNavigationBarHidden(true, animated: false)


    orangeView.navigationController?.setNavigationBarHidden(false, animated: false)

    greenView.navigationController?.setNavigationBarHidden(false, animated: false)





    let navController = UINavigationController(rootViewController: swipeNavigationController)

    self.present(navController, animated: true, completion: nil)

Below is all the code in the CameraVC

    class CameraViewController: SwiftyCamViewController, SwiftyCamViewControllerDelegate, SwipeNavigationControllerDelegate {




    let orangeVC = OrangeView()

    let greenVC = GreenView()
    let blueVC = BlueView()
    let pinkVC = PinkView()



    let flipCameraButton: UIButton = {
        let button = UIButton()
        let image = UIImage(named: "cameraSwitch")
        button.setImage(image, for: .normal)
        button.addTarget(self, action: #selector(cameraSwitchTapped), for: .touchUpInside)

        return button
    }()

    let captureButton: SwiftyRecordButton = {
        let button = SwiftyRecordButton(frame: CGRect(x: 150, y: 572, width: 75, height: 75))
        //let image = UIImage(named: "focus")
        //button.setImage(image, for: .normal)
        //button.addTarget(self, action: #selector(cameraTapped), for: .touchUpInside)




        return button
    }()



    let orangeButton: UIButton = {
        let button = UIButton()
        let image = UIImage(named: "OrangeIcon")
        button.setImage(image, for: .normal)
        button.addTarget(self, action: #selector(goToOrange), for: .touchUpInside)

        return button
    }()

    let greenButton: UIButton = {
        let button = UIButton()
        let image = UIImage(named: "GreenIcon")
        button.setImage(image, for: .normal)
        button.addTarget(self, action: #selector(goToGreen), for: .touchUpInside)

        return button
    }()

    let pinkButton: UIButton = {
        let button = UIButton()
        let image = UIImage(named: "pinkCameraIcon")
        button.setImage(image, for: .normal)
        button.addTarget(self, action: #selector(goToPink), for: .touchUpInside)

        return button
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        view.addSubview(flipCameraButton)
        view.addSubview(captureButton)
        view.addSubview(orangeButton)
        view.addSubview(greenButton)
        view.addSubview(pinkButton)

        shouldPrompToAppSettings = true
        cameraDelegate = self
        maximumVideoDuration = 10.0
        shouldUseDeviceOrientation = true
        allowAutoRotate = true
        audioEnabled = true


        // disable capture button until session starts
        captureButton.buttonEnabled = false

        navigationController?.isNavigationBarHidden = true

            UIApplication.shared.statusBarStyle = .lightContent
            navigationController?.isNavigationBarHidden = true

        setupViews()

    }


    override func viewWillAppear(_ animated: Bool) {
        UIApplication.shared.statusBarStyle = .lightContent
        navigationController?.isNavigationBarHidden = true

    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        captureButton.delegate = self

    }


    //


    @objc func goToOrange() {


        orangeVC.navigationController?.setNavigationBarHidden(false, animated: true)

        self.containerSwipeNavigationController?.showEmbeddedView(position: .left)
    }

    @objc func goToGreen() {


        greenVC.navigationController?.setNavigationBarHidden(false, animated: true)

        self.containerSwipeNavigationController?.showEmbeddedView(position: .right)


    }

    @objc func goToPink() {


        self.containerSwipeNavigationController?.showEmbeddedView(position: .bottom)
    }

    @objc func cameraSwitchTapped() {
        switchCamera()
    }

    @objc func cameraTapped() {
        print("CAMERA TAPPED")

        takePhoto()
    }




    func setupViews() {

        flipCameraButton.anchor(top: view.topAnchor, left: nil, bottom: nil, right: view.rightAnchor, paddingTop: 25, paddingLeft: 0, paddingBottom: 0, paddingRight: 12, width: 35, height: 35)

        captureButton.anchor(top: nil, left: nil, bottom: pinkButton.topAnchor, right: nil, paddingTop: 0, paddingLeft: 0, paddingBottom: 10, paddingRight: 0, width: 75, height: 75)
       captureButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true

        orangeButton.anchor(top: nil, left: view.leftAnchor, bottom: view.bottomAnchor, right: nil, paddingTop: 0, paddingLeft: 10, paddingBottom: 0, paddingRight: 0, width: 75, height: 75)

        greenButton.anchor(top: nil, left: nil, bottom: view.bottomAnchor, right: view.rightAnchor, paddingTop: 0, paddingLeft: 0, paddingBottom: 0, paddingRight: 10, width: 75, height: 75)

        pinkButton.anchor(top: nil, left: nil, bottom: view.bottomAnchor, right: nil, paddingTop: 0, paddingLeft: 0, paddingBottom: -10, paddingRight: 0, width: 75, height: 75)
        pinkButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true

        view.addSubview(flipCameraButton)
        view.addSubview(captureButton)
        view.addSubview(orangeButton)
        view.addSubview(greenButton)
        view.addSubview(pinkButton)
    }



    //MARK: Camera Protocols

    func swiftyCamSessionDidStartRunning(_ swiftyCam: SwiftyCamViewController) {
        print("Session did start running")
        captureButton.buttonEnabled = true
    }

    func swiftyCamSessionDidStopRunning(_ swiftyCam: SwiftyCamViewController) {
        print("Session did stop running")
        captureButton.buttonEnabled = false
    }


    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didTake photo: UIImage) {
        let newVC = AfterPhotoTakenView(image: photo)
        self.present(newVC, animated: true, completion: nil)
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didBeginRecordingVideo camera: SwiftyCamViewController.CameraSelection) {
        print("Did Begin Recording")
        captureButton.growButton()
        hideButtons()
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFinishRecordingVideo camera: SwiftyCamViewController.CameraSelection) {
        print("Did finish Recording")
        captureButton.shrinkButton()
        showButtons()
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFinishProcessVideoAt url: URL) {
        let newVC = VideoView(videoURL: url)
        self.present(newVC, animated: true, completion: nil)
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFocusAtPoint point: CGPoint) {
        print("Did focus at point: \(point)")
        focusAnimationAt(point)
    }

    func swiftyCamDidFailToConfigure(_ swiftyCam: SwiftyCamViewController) {
        let message = NSLocalizedString("Unable to capture media", comment: "Alert message when something goes wrong during capture session configuration")
        let alertController = UIAlertController(title: "AVCam", message: message, preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Alert OK button"), style: .cancel, handler: nil))
        present(alertController, animated: true, completion: nil)
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didChangeZoomLevel zoom: CGFloat) {
        print("Zoom level did change. Level: \(zoom)")
        print(zoom)
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didSwitchCameras camera: SwiftyCamViewController.CameraSelection) {
        print("Camera did change to \(camera.rawValue)")
        print(camera)
    }

    func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFailToRecordVideo error: Error) {
        print(error)
    }








    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }


}




extension CameraViewController {

    fileprivate func hideButtons() {
        UIView.animate(withDuration: 0.25) {

            self.flipCameraButton.alpha = 0.0
        }
    }

    fileprivate func showButtons() {
        UIView.animate(withDuration: 0.25) {

            self.flipCameraButton.alpha = 1.0
        }
    }

    fileprivate func focusAnimationAt(_ point: CGPoint) {
        let focusView = UIImageView(image: #imageLiteral(resourceName: "focus"))
        focusView.center = point
        focusView.alpha = 0.0
        view.addSubview(focusView)

        UIView.animate(withDuration: 0.25, delay: 0.0, options: .curveEaseInOut, animations: {
            focusView.alpha = 1.0
            focusView.transform = CGAffineTransform(scaleX: 1.25, y: 1.25)
        }) { (success) in
            UIView.animate(withDuration: 0.15, delay: 0.5, options: .curveEaseInOut, animations: {
                focusView.alpha = 0.0
                focusView.transform = CGAffineTransform(translationX: 0.6, y: 0.6)
            }) { (success) in
                focusView.removeFromSuperview()
            }
        }
    }

    fileprivate func toggleFlashAnimation() {
        if flashEnabled == true {
            //flashButton.setImage(#imageLiteral(resourceName: "flash"), for: UIControlState())
        } else {
            //flashButton.setImage(#imageLiteral(resourceName: "flashOutline"), for: UIControlState())
        }
    }
}

This is what it looks like when a user swipes to another view, as well as the buttons aren't responsive and the user can't swipe up or down for those views either.

Here is an example of a view I'm trying to present when the user swipes from left to right or clicks the pink messages button.

class MessagesView: UITableViewController {

override func viewDidLoad() {
    super.viewDidLoad()


    view.backgroundColor = UIColor.white

    setupNavBar()

    navigationController?.isNavigationBarHidden = false

    if #available(iOS 11.0, *) {
        navigationController?.navigationBar.prefersLargeTitles = true
        self.navigationController?.navigationBar.largeTitleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
    } else {
        // Fallback on earlier versions
    }


}

override func viewWillAppear(_ animated: Bool) {

    if #available(iOS 11.0, *) {
        navigationController?.navigationBar.prefersLargeTitles = true
        self.navigationController?.navigationBar.largeTitleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
        setupNavBar()
    } else {
        setupNavBar()
    }
}

func setupNavBar() {
    UIApplication.shared.statusBarStyle = .lightContent
    self.navigationController?.isNavigationBarHidden = false
    self.navigationController?.navigationBar.topItem?.title = "Messages"
    self.navigationController?.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: UIColor.white]
    self.navigationController?.navigationBar.barTintColor = UIColor.pinkNeonColor
    self.navigationController?.navigationBar.tintColor = UIColor.white
}

}

Answer 1

public enum Position {
case center
case top
case bottom
case left
case right
}

enum ActivePanDirection {
case undefined
case horizontal
case vertical
}


public protocol SwipeNavigationControllerDelegate: class {

func swipeNavigationController(_ controller: SwipeNavigationController, willShowEmbeddedViewForPosition position: Position)

func swipeNavigationController(_ controller: SwipeNavigationController, didShowEmbeddedViewForPosition position: Position)
}

open class SwipeNavigationController: SwiftyCamViewController, SwiftyCamViewControllerDelegate {

@IBOutlet fileprivate var currentXOffset: NSLayoutConstraint!
@IBOutlet fileprivate var currentYOffset: NSLayoutConstraint!

open fileprivate(set) weak var activeViewController: UIViewController!

public weak var delegate: SwipeNavigationControllerDelegate?

open fileprivate(set) var centerViewController: UIViewController!

open var topViewController: UIViewController? {
    willSet(newValue) {
        self.shouldShowTopViewController = newValue != nil
        guard let viewController = newValue else {

            return
        }
        addEmbeddedViewController(viewController, previousViewController: topViewController, position: .top)
    }
}
open var bottomViewController: UIViewController? {
    willSet(newValue) {
        self.shouldShowBottomViewController = newValue != nil
        guard let viewController = newValue else {
            return
        }
        addEmbeddedViewController(viewController, previousViewController: bottomViewController, position: .bottom)
    }
}
open var leftViewController: UIViewController? {
    willSet(newValue) {
        self.shouldShowLeftViewController = newValue != nil
        guard let viewController = newValue else {
            return
        }
        addEmbeddedViewController(viewController, previousViewController: leftViewController, position: .left)
    }
}
open var rightViewController: UIViewController? {
    willSet(newValue) {
        self.shouldShowRightViewController = newValue != nil
        guard let viewController = newValue else {
            return
        }
        addEmbeddedViewController(viewController, previousViewController: rightViewController, position: .right)
    }
}

open override var shouldAutomaticallyForwardAppearanceMethods: Bool {
    get {
        return false
    }
}

@IBOutlet fileprivate var mainPanGesture: UIPanGestureRecognizer!
fileprivate var previousNonZeroDirectionChange = CGVector(dx: 0.0, dy: 0.0)
fileprivate var activePanDirection = ActivePanDirection.undefined
fileprivate let verticalSnapThresholdFraction: CGFloat = 0.15
fileprivate let horizontalSnapThresholdFraction: CGFloat = 0.15

fileprivate var centerContainerOffset: CGVector!
fileprivate var topContainerOffset: CGVector!
fileprivate var bottomContainerOffset: CGVector!
fileprivate var leftContainerOffset: CGVector!
fileprivate var rightContainerOffset: CGVector!

open var shouldShowTopViewController = true
open var shouldShowBottomViewController = true
open var shouldShowLeftViewController = true
open var shouldShowRightViewController = true
open var shouldShowCenterViewController = true

fileprivate let swipeAnimateDuration = 0.2

public init(centerViewController: UIViewController) {
    super.init(nibName: nil, bundle: nil)
    shouldShowTopViewController = false
    shouldShowBottomViewController = false
    shouldShowLeftViewController = false
    shouldShowRightViewController = false
    self.centerViewController = centerViewController
    addChildViewController(centerViewController)
    centerViewController.didMove(toParentViewController: self)
}


public func swiftyCamSessionDidStartRunning(_ swiftyCam: SwiftyCamViewController) {
    print("Session did start running")
    captureButton.buttonEnabled = true
}

public func swiftyCamSessionDidStopRunning(_ swiftyCam: SwiftyCamViewController) {
    print("Session did stop running")
    captureButton.buttonEnabled = false
}

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didTake photo: UIImage) {
    let newVC = PhotoViewController(image: photo)
    self.present(newVC, animated: true, completion: nil)
}

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didBeginRecordingVideo camera: SwiftyCamViewController.CameraSelection) {
        print("Did Begin Recording")
        captureButton.growButton()
        hideButtons()
    }

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFinishRecordingVideo camera: SwiftyCamViewController.CameraSelection) {
        print("Did finish Recording")
        captureButton.shrinkButton()
        showButtons()
    }

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFinishProcessVideoAt url: URL) {
        let newVC = VideoViewController(videoURL: url)
        self.present(newVC, animated: true, completion: nil)
    }

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFocusAtPoint point: CGPoint) {
        print("Did focus at point: \(point)")
        focusAnimationAt(point)
    }

public func swiftyCamDidFailToConfigure(_ swiftyCam: SwiftyCamViewController) {
    let message = NSLocalizedString("Unable to capture media", comment: "Alert message when something goes wrong during capture session configuration")
    let alertController = UIAlertController(title: "AVCam", message: message, preferredStyle: .alert)
    alertController.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Alert OK button"), style: .cancel, handler: nil))
    present(alertController, animated: true, completion: nil)
}

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didChangeZoomLevel zoom: CGFloat) {
    print("Zoom level did change. Level: \(zoom)")
    print(zoom)
}

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didSwitchCameras camera: SwiftyCamViewController.CameraSelection) {
    print("Camera did change to \(camera.rawValue)")
    print(camera)
}

public func swiftyCam(_ swiftyCam: SwiftyCamViewController, didFailToRecordVideo error: Error) {
    print(error)
}
public required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
}

let flipCameraButton: UIButton = {
    let button = UIButton()
    let image = UIImage(named: "cameraSwitch")
    button.setImage(image, for: .normal)
    button.addTarget(self, action: #selector(cameraSwitchTapped), for: .touchUpInside)

    return button
}()

let captureButton: SwiftyRecordButton = {
    let button = SwiftyRecordButton(frame: CGRect(x: 150, y: 572, width: 75, height: 75))
    let image = UIImage(named: "focus")
    button.setImage(image, for: .normal)
    button.addTarget(self, action: #selector(cameraTapped), for: .touchUpInside)
    return button
}()

let orangeButton: UIButton = {
    let button = UIButton()
    let image = UIImage(named: "OrangeIcon")
    button.setImage(image, for: .normal)
    button.addTarget(self, action: #selector(goToOrange), for: .touchUpInside)

    return button
}()

let greenButton: UIButton = {
    let button = UIButton()
    let image = UIImage(named: "GreenIcon")
    button.setImage(image, for: .normal)
    button.addTarget(self, action: #selector(goToGreen), for: .touchUpInside)

    return button
}()

let pinkButton: UIButton = {
    let button = UIButton()
    let image = UIImage(named: "pinkCameraIcon")
    button.setImage(image, for: .normal)
    button.addTarget(self, action: #selector(goToPink), for: .touchUpInside)

    return button
}()

@objc func goToOrange() {
    //orangeVC.navigationController?.setNavigationBarHidden(false, animated: true)
    self.containerSwipeNavigationController?.showEmbeddedView(position: .left)
}

@objc func goToGreen() {
    //greenVC.navigationController?.setNavigationBarHidden(false, animated: true)
    self.containerSwipeNavigationController?.showEmbeddedView(position: .right)
}

@objc func goToPink() {
    self.containerSwipeNavigationController?.showEmbeddedView(position: .bottom)
}

@objc func cameraSwitchTapped() {
    switchCamera()
}

@objc func cameraTapped() {
    print("CAMERA TAPPED")

    takePhoto()
}

// Mark: - Functions
open override func viewDidLoad() {
    super.viewDidLoad()
    self.cameraDelegate = self

    if currentXOffset == nil && currentYOffset == nil {
        view.addSubview(centerViewController.view)
        centerViewController.view.isHidden = true
        centerViewController.view.translatesAutoresizingMaskIntoConstraints = false
        self.currentXOffset = alignCenterXConstraint(forItem: centerViewController.view, toItem: view, position: .center)
        self.currentYOffset = alignCenterYConstraint(forItem: centerViewController.view, toItem: view, position: .center)
        view.addConstraints([self.currentXOffset, self.currentYOffset])
        view.addConstraints(sizeConstraints(forItem: centerViewController.view, toItem: view))
    }

    testViewdid()
    assert(currentXOffset != nil && currentYOffset != nil, "both currentXOffset and currentYOffset must be set")

    if mainPanGesture == nil {
        mainPanGesture = UIPanGestureRecognizer(target: self, action: #selector(onPanGestureTriggered(sender:)))
        view.addGestureRecognizer(mainPanGesture)
    }


    let frameWidth = view.frame.size.width
    let frameHeight = view.frame.size.height
    centerContainerOffset = CGVector(dx: currentXOffset.constant, dy: currentYOffset.constant)
    topContainerOffset = CGVector(dx: centerContainerOffset.dx, dy: centerContainerOffset.dy + frameHeight)
    bottomContainerOffset = CGVector(dx: centerContainerOffset.dx, dy: centerContainerOffset.dy - frameHeight)
    leftContainerOffset = CGVector(dx: centerContainerOffset.dx + frameWidth, dy: centerContainerOffset.dy)
    rightContainerOffset = CGVector(dx: centerContainerOffset.dx - frameWidth, dy: centerContainerOffset.dy)
    activeViewController = centerViewController
}

open override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    activeViewController.beginAppearanceTransition(true, animated: animated)

}

open override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    activeViewController.endAppearanceTransition()
    captureButton.delegate = self

}

open override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    activeViewController.beginAppearanceTransition(false, animated: animated)
}

open override func viewDidDisappear(_ animated: Bool) {
    super.viewDidDisappear(animated)
    activeViewController.endAppearanceTransition()
}

func testViewdid() {
    view.addSubview(flipCameraButton)
    view.addSubview(captureButton)
    view.addSubview(orangeButton)
    view.addSubview(greenButton)
    view.addSubview(pinkButton)

    shouldPrompToAppSettings = true
    cameraDelegate = self
    maximumVideoDuration = 10.0
    shouldUseDeviceOrientation = true
    allowAutoRotate = true
    audioEnabled = true
    captureButton.buttonEnabled = true

    navigationController?.isNavigationBarHidden = true

    UIApplication.shared.statusBarStyle = .lightContent
    navigationController?.isNavigationBarHidden = true

    //setupViews()
}

// Let UIKit handle rotation forwarding calls
open override func shouldAutomaticallyForwardRotationMethods() -> Bool {
    return true
}

// MARK: - Containers
open func showEmbeddedView(position: Position) {
    weak var disappearingViewController: UIViewController?
    let targetOffset: CGVector

    switch position {
    case .center:

        if !activeViewController.isEqual(centerViewController) {
            disappearingViewController = activeViewController
        }
        activeViewController = centerViewController
        targetOffset = centerContainerOffset
    case .top:
        activeViewController = topViewController
        targetOffset = topContainerOffset
    case .bottom:
        activeViewController = bottomViewController
        targetOffset = bottomContainerOffset
    case .left:
        activeViewController = leftViewController
        targetOffset = leftContainerOffset
    case .right:
        activeViewController = rightViewController
        targetOffset = rightContainerOffset
    }

    if !activeViewController.isEqual(centerViewController) {
        disappearingViewController = centerViewController
    }

    currentXOffset.constant = targetOffset.dx
    currentYOffset.constant = targetOffset.dy
    disappearingViewController?.beginAppearanceTransition(false, animated: true)
    activeViewController.beginAppearanceTransition(true, animated: true)
    delegate?.swipeNavigationController(self, willShowEmbeddedViewForPosition: position)
    UIView.animate(withDuration: swipeAnimateDuration, animations: {
        self.view.layoutIfNeeded()
    }) { (finished) in
        self.delegate?.swipeNavigationController(self, didShowEmbeddedViewForPosition: position)
        self.activeViewController.endAppearanceTransition()
        disappearingViewController?.endAppearanceTransition()
    }
}

open func isContainerActive(position: Position) -> Bool {
    let targetOffset: CGVector
    switch position {
    case .center:
        targetOffset = centerContainerOffset
    case .top:
        targetOffset = topContainerOffset
    case .bottom:
        targetOffset = bottomContainerOffset
    case .left:
        targetOffset = leftContainerOffset
    case .right:
        targetOffset = rightContainerOffset
    }
    return (currentXOffset.constant, currentYOffset.constant) == (targetOffset.dx, targetOffset.dy)
}


open func lock() {
    self.mainPanGesture.isEnabled = false
}
open func unlock() {
    self.mainPanGesture.isEnabled = true
}

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
    return true
}

@IBAction fileprivate func onPanGestureTriggered(sender: UIPanGestureRecognizer) {
    switch sender.state {
    case .began:

        if isContainerActive(position: .top) || isContainerActive(position: .bottom) {
            activePanDirection = .vertical
        } else if isContainerActive(position: .left) || isContainerActive(position: .right) {
            activePanDirection = .horizontal
        } else {
            activePanDirection = .undefined
        }

    case .changed:

        let translationInMainView = sender.translation(in: view)

        if translationInMainView.x != 0 {
            previousNonZeroDirectionChange.dx = translationInMainView.x
        }

        if translationInMainView.y != 0 {
            previousNonZeroDirectionChange.dy = translationInMainView.y
        }

        switch activePanDirection {
        case .undefined:
            activePanDirection = fabs(translationInMainView.x) > fabs(translationInMainView.y) ? .horizontal : .vertical

        case .horizontal:

            let isCurrentlyShowingRightViewController = currentXOffset.constant < centerContainerOffset.dx
            let isCurrentlyShowingLeftViewController = currentXOffset.constant > centerContainerOffset.dx
            let minX = isCurrentlyShowingRightViewController || shouldShowRightViewController ? rightContainerOffset.dx : centerContainerOffset.dx
            let maxX = isCurrentlyShowingLeftViewController || shouldShowLeftViewController ? leftContainerOffset.dx : centerContainerOffset.dx

            if shouldShowCenterViewController {
                currentXOffset.constant = min(max(minX, currentXOffset.constant + translationInMainView.x), maxX)
            }
        case .vertical:

            let isCurrentlyShowingBottomViewController = currentYOffset.constant < centerContainerOffset.dy
            let isCurrentlyShowingTopViewController = currentYOffset.constant > centerContainerOffset.dy
            let minY = isCurrentlyShowingBottomViewController || shouldShowBottomViewController ? bottomContainerOffset.dy : centerContainerOffset.dy
            let maxY = isCurrentlyShowingTopViewController || shouldShowTopViewController ? topContainerOffset.dy : centerContainerOffset.dy

            if shouldShowCenterViewController {
                currentYOffset.constant = min(max(minY, currentYOffset.constant + translationInMainView.y), maxY)
            }
        }

        // reset translation for next iteration
        sender.setTranslation(CGPoint.zero, in: view)

    case .ended:
        /*
         * Handle snapping here
         */
        switch activePanDirection {
        case .horizontal:

            if currentXOffset.constant > 0.0 {

                // within range of center container
                if currentXOffset.constant < (horizontalSnapThresholdFraction * view.frame.size.width) {
                    showEmbeddedView(position: .center)
                }

                    // within range of left container
                else if currentXOffset.constant > ((1.0 - horizontalSnapThresholdFraction) * view.frame.size.width) {
                    showEmbeddedView(position: .left)
                }

                    // center region: depends on inertia direction
                else {
                    // pulled right
                    if previousNonZeroDirectionChange.dx > 0.0 {
                        showEmbeddedView(position: .left)
                    }

                        // pulled left
                    else {
                        showEmbeddedView(position: .center)
                    }
                }
            }

            else if currentXOffset.constant < 0.0 {

                // within range of center container
                if currentXOffset.constant > (horizontalSnapThresholdFraction * -view.frame.size.width) {
                    showEmbeddedView(position: .center)
                }

                    // within range of right container
                else if currentXOffset.constant < ((1.0 - horizontalSnapThresholdFraction) * -view.frame.size.width) {
                    showEmbeddedView(position: .right)
                }

                    // center region: depends on inertia direction
                else {
                    // pulled left
                    if previousNonZeroDirectionChange.dx < 0.0 {
                        showEmbeddedView(position: .right)
                    }

                        // pulled right
                    else {
                        showEmbeddedView(position: .center)
                    }
                }
            }

        case .vertical:
            if currentYOffset.constant > 0.0 {

                if currentYOffset.constant < (verticalSnapThresholdFraction * view.frame.size.height) {
                    showEmbeddedView(position: .center)
                }

                else if currentYOffset.constant > ((1.0 - verticalSnapThresholdFraction) * view.frame.size.height) {
                    showEmbeddedView(position: .top)
                }
                else {

                    if previousNonZeroDirectionChange.dy > 0.0 {
                        showEmbeddedView(position: .top)
                    }

                    else {
                        showEmbeddedView(position: .center)
                    }
                }
            }

            else if currentYOffset.constant < 0.0 {

                if currentYOffset.constant > (verticalSnapThresholdFraction * -view.frame.size.height) {
                    showEmbeddedView(position: .center)
                }

                else if currentYOffset.constant < ((1.0 - verticalSnapThresholdFraction) * -view.frame.size.height) {
                    showEmbeddedView(position: .bottom)
                }
                else {

                    if previousNonZeroDirectionChange.dy < 0.0 {

                        showEmbeddedView(position: .bottom)
                    }

                    else {
                        showEmbeddedView(position: .center)
                    }
                }
            }

        case .undefined:
            break
        }
    default:
        break
    }
}

func addEmbeddedViewController(_ viewController: UIViewController, previousViewController: UIViewController?, position: Position) {
    if viewController.isEqual(previousViewController) {
        return
    }
    previousViewController?.beginAppearanceTransition(false, animated: false)
    previousViewController?.view.removeFromSuperview()
    previousViewController?.endAppearanceTransition()
    previousViewController?.willMove(toParentViewController: nil)
    previousViewController?.removeFromParentViewController()

    addChildViewController(viewController)
    view.addSubview(viewController.view)
    view.sendSubview(toBack: viewController.view)
    viewController.view.translatesAutoresizingMaskIntoConstraints = false
    viewController.didMove(toParentViewController: self)
    view.addConstraint(alignCenterXConstraint(forItem: viewController.view, toItem: centerViewController.view, position: position))
    view.addConstraint(alignCenterYConstraint(forItem: viewController.view, toItem: centerViewController.view, position: position))
    view.addConstraints(sizeConstraints(forItem: viewController.view, toItem: centerViewController.view))
}

func alignCenterXConstraint(forItem item: UIView, toItem: UIView, position: Position) -> NSLayoutConstraint {
    let offset = position == .left ? -self.view.frame.width : position == .right ? toItem.frame.width : 0
    return NSLayoutConstraint(item: item, attribute: .centerX, relatedBy: .equal, toItem: toItem, attribute: .centerX, multiplier: 1, constant: offset)
}

func alignCenterYConstraint(forItem item: UIView, toItem: UIView, position: Position) -> NSLayoutConstraint {
    let offset = position == .top ? -self.view.frame.height : position == .bottom ? toItem.frame.height : 0
    return NSLayoutConstraint(item: item, attribute: .centerY, relatedBy: .equal, toItem: toItem, attribute: .centerY, multiplier: 1, constant: offset)
}

func sizeConstraints(forItem item: UIView, toItem: UIView) -> [NSLayoutConstraint] {
    let widthConstraint = NSLayoutConstraint(item: item, attribute: .width, relatedBy: .equal, toItem: toItem, attribute: .width, multiplier: 1, constant: 0)
    let heightConstraint = NSLayoutConstraint(item: item, attribute: .height, relatedBy: .equal, toItem: toItem, attribute: .height, multiplier: 1, constant: 0)
    return [widthConstraint, heightConstraint]
}
func hideButtons() {
    UIView.animate(withDuration: 0.25) {

        self.flipCameraButton.alpha = 0.0
    }
}

 func showButtons() {
    UIView.animate(withDuration: 0.25) {

        self.flipCameraButton.alpha = 1.0
    }
}

 func focusAnimationAt(_ point: CGPoint) {
    let focusView = UIImageView(image: #imageLiteral(resourceName: "focus"))
    focusView.center = point
    focusView.alpha = 0.0
    view.addSubview(focusView)

    UIView.animate(withDuration: 0.25, delay: 0.0, options: .curveEaseInOut, animations: {
        focusView.alpha = 1.0
        focusView.transform = CGAffineTransform(scaleX: 1.25, y: 1.25)
    }) { (success) in
        UIView.animate(withDuration: 0.15, delay: 0.5, options: .curveEaseInOut, animations: {
            focusView.alpha = 0.0
            focusView.transform = CGAffineTransform(translationX: 0.6, y: 0.6)
        }) { (success) in
            focusView.removeFromSuperview()
        }
    }
}

 func toggleFlashAnimation() {
    if flashEnabled == true {
        //flashButton.setImage(#imageLiteral(resourceName: "flash"), for: UIControlState())
    } else {
        //flashButton.setImage(#imageLiteral(resourceName: "flashOutline"), for: UIControlState())
    }
}
}

CameraViewControler -

class CameraViewController: UIViewController {
override func viewDidLoad() {
    super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
    UIApplication.shared.statusBarStyle = .lightContent
    navigationController?.isNavigationBarHidden = true

}
}