How to adjust space between two UIBarButtonItem in rightBarButtonItems

Question

I am using the following codes to add two button to self.navigationItem.rightBarButtonItems, and I think in iOS7, the space between two buttons are too wide, is there a way

Answer 1

Without any code. I just put another UIBarButtonItem in-between the buttons that need spacing in storyboard. The button is just a placeholder for spacing and the UIBarButton should have UIView as subview of the UIBarButtonItem. adjust the view's width for your spacing. See Screen shots.

Answer 2

another answer : It works in ios 9 - 12. You should call fixNavigationItemsMargin(margin:) in function viewDidAppear(_ animated: Bool) and viewDidLayoutSubviews(). fixNavigationItemsMargin(margin:) would modify the UINavigationController stack.

you could call fixNavigationItemsMargin(margin:) in BaseNavigationController ,do the common work. And call fixNavigationItemsMargin(margin:) in UIViewController do precise layout.

// do common initilizer
class BaseNavigationController: UINavigationController {
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        fixNavigationItemsMargin()
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        fixNavigationItemsMargin()
    }

}

extension UINavigationController {
func fixNavigationItemsMargin(_ margin: CGFloat = 8) {
    let systemMajorVersion = ProcessInfo.processInfo.operatingSystemVersion.majorVersion
    if systemMajorVersion >= 11 {
        // iOS >= 11
        guard let contentView = navigationBar.subviews
            .first(
                where: { sub in
                    String(describing: sub).contains("ContentView")
            }) else { return }

        // refer to: https://www.matrixprojects.net/p/uibarbuttonitem-ios11/
        // if rightBarButtonItems has not any custom views, then margin would be 8(320|375)/12(414)
        // should use customView
        let needAdjustRightItems: Bool
        if let currentVC = viewControllers.last,
            let rightItems = currentVC.navigationItem.rightBarButtonItems,
            rightItems.count > 0,
            rightItems.filter({ $0.customView != nil }).count > 0 {
            needAdjustRightItems = true
        } else {
            print("Use 8(320|375)/12(414), if need precious margin ,use UIBarButtonItem(customView:)!!!")
            needAdjustRightItems = false
        }

        let needAdjustLeftItems: Bool
        if let currentVC = viewControllers.last,
            let leftItems = currentVC.navigationItem.leftBarButtonItems,
            leftItems.count > 0,
            leftItems.filter({ $0.customView != nil }).count > 0 {
            needAdjustLeftItems = true
        } else {
            print("Use 8(320|375)/12(414), if need precious margin ,use UIBarButtonItem(customView:)!!!")
            needAdjustLeftItems = false
        }

        let layoutMargins: UIEdgeInsets
        if #available(iOS 11.0, *) {
            let directionInsets = contentView.directionalLayoutMargins
            layoutMargins = UIEdgeInsets(
                top: directionInsets.top,
                left: directionInsets.leading,
                bottom: directionInsets.bottom,
                right: directionInsets.trailing)
        } else {
            layoutMargins = contentView.layoutMargins
        }

        contentView.constraints.forEach(
            { cst in

                // iOS 11 the distance between rightest item and NavigationBar should be  margin
                // rightStackView trailing space is -margin / 2
                // rightestItem trailing to rightStackView trailing is -margin / 2
                let rightConstant = -margin / 2

                switch (cst.firstAttribute, cst.secondAttribute) {
                case (.leading, .leading), (.trailing, .trailing):

                    if let stackView = cst.firstItem as? UIStackView,
                        stackView.frame.minX < navigationBar.frame.midX {
                        // is leftItems
                        if needAdjustLeftItems {
                            cst.constant = margin - layoutMargins.left
                        }
                    } else if let layoutGuide = cst.firstItem as? UILayoutGuide,
                        layoutGuide.layoutFrame.minX < navigationBar.frame.midX {
                        // is leftItems
                        if needAdjustLeftItems {
                            cst.constant = margin - layoutMargins.left
                        }
                    }

                    if let stackView = cst.firstItem as? UIStackView,
                        stackView.frame.maxX > navigationBar.frame.midX {
                        // is rightItems
                        if needAdjustRightItems {
                            cst.constant = rightConstant
                        }
                    } else if let layoutGuide = cst.firstItem as? UILayoutGuide,
                        layoutGuide.layoutFrame.maxX > navigationBar.frame.midX {
                        // is rightItems
                        if needAdjustRightItems {
                            cst.constant = rightConstant
                        }
                    }

                default: break
                }

        })

        // ensure items space == 8， minispcae
        contentView.subviews.forEach(
            { subsub in
                guard subsub is UIStackView else { return }
                subsub.constraints.forEach(
                    { cst in
                        guard cst.firstAttribute == .width
                            || cst.secondAttribute == .width
                            else { return }
                        cst.constant = 0
                })
        })

    } else {
        // iOS < 11

        let versionItemsCount: Int
        if systemMajorVersion == 10 {
            // iOS 10 navigationItem.rightBarButtonItems == 0
            // space = 16(320|375) / 20(414)
            // should adjust margin
            versionItemsCount = 0
        } else {
            // iOS 9 navigationItem.rightBarButtonItems == 0
            // space = 8(320|375) / 12(414)
            // should not adjust margin
            versionItemsCount = 1
        }

        let spaceProducer = { () -> UIBarButtonItem in
            let spaceItem = UIBarButtonItem(
                barButtonSystemItem: .fixedSpace,
                target: nil,
                action: nil)
            spaceItem.width = margin - 16
            return spaceItem
        }
        if let currentVC = viewControllers.last,
            var rightItems = currentVC.navigationItem.rightBarButtonItems,
            rightItems.count > versionItemsCount,
            let first = rightItems.first {

            // ensure the first BarButtonItem is NOT fixedSpace
            if first.title == nil && first.image == nil && first.customView == nil {
                print("rightBarButtonItems SPACE SETTED!!!  SPACE: ", abs(first.width))

            } else {
                rightItems.insert(spaceProducer(), at: 0)

                // arranged right -> left
                currentVC.navigationItem.rightBarButtonItems = rightItems
            }
        }

        if let currentVC = viewControllers.last,
            var leftItems = currentVC.navigationItem.leftBarButtonItems,
            leftItems.count > versionItemsCount,
            let first = leftItems.first {
            if first.title == nil && first.image == nil && first.customView == nil {
                print("leftBarButtonItems  SPACE SETTED!!!  SPACE: ", abs(first.width))
            } else {
                leftItems.insert(spaceProducer(), at: 0)

                // arranged left -> right
                currentVC.navigationItem.leftBarButtonItems = leftItems
            }
        }
    }
}
}

// do precise layout
class ViewController: UIViewController {
  override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()
    navigationController?.fixNavigationItemsMargin(40)
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    navigationController?.fixNavigationItemsMargin(40)
}