如何以编程方式解开或在背面UIBarButton上弹出多个viewControllers？

Question

我有以下方式的6个viewControllers。 VCA，VCB，VCC，VCD，VCE，VCF。

mainVC - ＆GT; VCA - ＆GT; VCB - ＆GT; VCC - ＆GT; VCD ... {{1 }}

VCE - ＆GT; mainVC - ＆GT; VCA ... VCD

（ - ＆gt;）通过segues连接，而（...）VCF和VCE是以编程方式VCF。

我的问题是如何在pushed in navigationController上的VCD UIBarButton上从VCE，VCF或VCA到Back弹出多个viewControllers < / p>

根据此StackOverFlow问题Link和Link： -

尝试了这段代码，但它没有用。

navigationController

Answer 1

如果您知道VCA已被推送到mainVC，那么您的导航控制器堆栈为[mainVC, VCA, VCB, ..., VCF]或[mainVC, VCA, VCD, ..., VCF]，因此您希望在项目中弹回VC堆栈中的一个：

func back(sender: UIBarButtonItem) {

        if let vc = navigationController?.viewControllers[1] {
            _ = navigationController?.popToViewController(vc, animated: true)
        }

}

如果你真正想做的是回到导航控制器的 root VC，你可以简单地说：

func back(sender: UIBarButtonItem) {

        _ = navigationController?.popToRootViewController(animated: true)

}

修改

其他信息：

// if you want to pop to the First VC, regardless of VC type
func popToFirst() {

    if let vc = navigationController?.viewControllers[1] {
        _ = navigationController?.popToViewController(vc, animated: true)
    } else {
        print("NO VC found as element 1 in navigation controller's stack")
    }

}

// if you want to pop to the First VC, but
// *only* if it is an instance of VCAViewController
func popToFirstOnlyIfA() {

    if let vc = navigationController?.viewControllers[1] as? VCAViewController {
        _ = navigationController?.popToViewController(vc, animated: true)
    } else {
        print("viewControllers[1] is NOT an instance of VCAViewController")
    }

}

// if you want to pop to an instance of VCAViewController,
// whether it's the root, first, second, third, etc VC in the stack
func popToAAnywhereInTheStack() {

    guard let aVCs = navigationController?.viewControllers else {
        print("No Array of View Controllers from navigationController!")
        return
    }

    for vc in aVCs {
        if vc is VCAViewController {
            _ = navigationController?.popToViewController(vc, animated: true)
            return
        }
    }

    print("No instance of VCAViewController found in the stack")

}

// if you simply want to pop to the navigation controller's Root VC
func popToRoot() {

    _ = navigationController?.popToRootViewController(animated: true)

}

Answer 2

从当前视图控制器（它将是最后一个）和视图控制器之间的navigationController?.viewControllers删除所有视图控制器，然后执行navigationController?.popViewController(animated: true)