iOS 10 barTintColor 动画

Question

我注意到 ios 10 中条形色调颜色的动画方式发生了变化。我创建了一个示例项目来概述变化:Github: ios10BarTintDemo

基本上在 ios 9 上，barTintColor 使用 [UIViewControllerTransitionCoordinator animateAlongsideTransition]

平滑地设置动画

但是在 ios 10 上，动画不太流畅，当弹出 View Controller 时根本没有动画，我尝试添加 [self.navigationController.navigationBar layoutIfNeeded] 一些类似的答案，但这在推送/弹出 Controller 时似乎没有任何效果。

Answer 1

更新

我已经在 iOS 10.3 中进行了测试，我认为问题已解决。并且 transitionCordinator 不再需要了。我觉得动画很流畅。请查看我的project on github或者看看这段代码:

class ViewControllerA: UIViewController {

    override func loadView() {
        super.loadView()
        title = "A"
        view.backgroundColor = .white
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "NEXT", style: .plain, target: self, action: #selector(self.showController))
    }

    override func viewWillAppear(_ animated: Bool) {
        setColors()
        super.viewWillAppear(animated)
    }

    func showController() {
        navigationController?.pushViewController(ViewControllerB(), animated: true)
    }

    private func setColors() {
        navigationController?.navigationBar.tintColor = .black
        navigationController?.navigationBar.barTintColor = .red
        navigationController?.navigationBar.isTranslucent = false
    }
}




class ViewControllerB: UIViewController {

    override func loadView() {
        super.loadView()
        title = "B"
        view.backgroundColor = .white
    }

    override func viewWillAppear(_ animated: Bool) {
        setColors()
        super.viewWillAppear(animated)
    }

    override func willMove(toParentViewController parent: UIViewController?) {
        if parent == nil {
            navigationController?.navigationBar.barTintColor = .red
        }
        super.willMove(toParentViewController: parent)
    }


    private func setColors() {
        navigationController?.navigationBar.tintColor = .black
        navigationController?.navigationBar.barTintColor = .blue
        navigationController?.navigationBar.isTranslucent = false
    }
}

============================================= ================================================ ================================================ ================================================ ================================================ ================================================ ===

要实现这种动画，您应该使用 UIViewControllerTransitionCoordinator 作为 Apple documentation说它是:

An object that adopts the UIViewControllerTransitionCoordinator protocol provides support for animations associated with a view controller transition.(...)

所以每个 UIViewController 都有自己的 transitionController。为此，您应该在 UIViewControllerClass 中调用:

self.transitionCoordinator()

来自 documentation :

Returns the active transition coordinator object.

因此，为了获得您想要的结果，您应该在 viewController transitionCoordinatior 中实现 animateAlongsideTransition 方法。当您单击 backButton 并向后滑动时，动画会起作用。

示例:

第一个 Controller :

class ViewControllerA: UIViewController {

    override func loadView() {
        super.loadView()
        title = "A"
        view.backgroundColor = .white
        navigationItem.rightBarButtonItem = UIBarButtonItem(title: "NEXT", style: .plain, target: self, action: #selector(self.showController))
        setColors()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        animate()
    }

    func showController() {
        navigationController?.pushViewController(ViewControllerB(), animated: true)
    }

    private func animate() {
        guard let coordinator = self.transitionCoordinator else {
            return
        }

        coordinator.animate(alongsideTransition: {
            [weak self] context in
            self?.setColors()
        }, completion: nil)
    }

    private func setColors() {
        navigationController?.navigationBar.tintColor = .black
        navigationController?.navigationBar.barTintColor = .red
    }
}

第二个 Controller :

class ViewControllerB : UIViewController {

    override func loadView() {
        super.loadView()
        title = "B"
        view.backgroundColor = .white
        setColors()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        animate()
    }

    override func willMove(toParentViewController parent: UIViewController?) { // tricky part in iOS 10
        navigationController?.navigationBar.barTintColor = .red //previous color
        super.willMove(toParentViewController: parent)
    }

    override func viewDidAppear(_ animated: Bool) {
        navigationController?.navigationBar.barTintColor = .blue
    }

    private func animate() {
        guard let coordinator = self.transitionCoordinator else {
            return
        }
        coordinator.animate(alongsideTransition: {
            [weak self] context in
            self?.setColors()
        }, completion: nil)
    }

    private func setColors(){
        navigationController?.navigationBar.tintColor = .black
        navigationController?.navigationBar.barTintColor = .blue
    }

}

更新 iOS 10

在 iOS 10 中，棘手的部分是在 second ViewController 中添加 willMoveTo(parentViewController parent: UIViewController?)。并将导航栏 tintColor 设置为 previous Controller 的颜色值。此外，在 second ViewControler 的 viewDidAppear 方法中，将 navigationBar.tintColor 设置为 第二个 viewController。

查看我的示例 project on github