iOS 10 barTintColor动画

Question

我注意到ios 10中条形图颜色动画的方式发生了变化。

基本上，在ios 9上，barTintColor使用[UIViewControllerTransitionCoordinator animateAlongsideTransition]平稳地动画。

但是在ios 10上，动画就不那么流畅了，当弹出一个视图控制器时，我尝试了添加一些类似的答案中提到的[self.navigationController.navigationBar layoutIfNeeded]，但是在推送/弹出控制器时，这似乎没有任何效果。

Answer 1

更新

我在iOS 10.3中进行了测试，我认为问题已经解决了。transitionCordinator也不再需要了。我觉得动画很流畅。请查看我的github项目或查看以下代码：

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，就像苹果文档说的那样：

采用UIViewControllerTransitionCoordinator协议的对象提供对与视图控制器转换相关联的动画的支持。

所以每个UIViewController都有自己的transitionController。要获得这个结果，您应该调用UIViewControllerClass：

self.transitionCoordinator()

来自文档

返回活动转换协调器对象。

因此，要获得您想要的结果，您应该在viewController transitionCoordinatior中实现viewController方法。当您单击backButton并向后滑动时，动画工作。

例子：

​

​

第一任主计长：

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
    }
}

第二主计长：

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，棘手的部分是在第二个 ViewController中添加willMoveTo(parentViewController parent: UIViewController?)。并将navigationBar tintColor设置为以前的控制器的颜色值。此外，在viewDidAppear方法中，第二次 ViewControler将navigationBar.tintColor设置为来自第二 viewController的颜色。

查看了我的示例 https://github.com/k8mil/NavBarColorAnimation

Answer 2

您可以通过添加类似于此的内容来解决这个弹出问题，在viewWillDisappear中运行它在iOS10中由于某种原因无法工作。

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