Question

我有一个主视图控制器，在这个视图控制器中我将另一个视图控制器显示为其子视图控制器。显示子视图控制器的代码如下所示。 self.currentController是子控制器，它将位于主控制器内。

        self.addChildViewController(self.currentController!)
        self.currentController?.view.frame = self.operationView.bounds
        self.currentController?.view.layoutIfNeeded()
        self.operationView.addSubview((self.currentController?.view!)!)
        self.setNeedsStatusBarAppearanceUpdate()

现在我想通过使用下面的代码在子视图控制器中执行show segue（另一个控制器，让我们称之为ThirdController）：

performSegueWithIdentifier("ShowSegue", sender: nil)

这样做，ThirdController将填满全屏。我想要做的是在子控制器位置显示第三个控制器。我怎么能这样做？

Answer 1

好的，抱歉，我不知道如何在Swift中写出答案。所以我将向您展示我的解决方案是如何在Objective-C中完成的。

加载第一个子视图的代码：

- (void)loadASubview
{
    subview = [self.storyboard instantiateViewControllerWithIdentifier:@"FirstView"];

    [self addChildViewController:subview];
    [self.view addSubview:subview.view];

    [subview didMoveToParentViewController:self];
    [subview.view setFrame:self.view.bounds];
}

卸载子视图的代码：

- (void)unloadASubview
{
    [subview willMoveToParentViewController:nil];
    [subview.view removeFromSuperview];
    [subview removeFromParentViewController];
}

最初，当我需要加载子视图A时，我只需调用 loadASubview 。之后，如果我需要加载另一个子视图，我将在加载新子视图之前通过调用unloadASubview卸载我之前加载的子视图。

请注意，函数内的“subview”变量在外部声明。

我希望这会对你有所帮助。

Answer 2

Swift 4

func loadASubView(){
    subview = self.storyboard?.instantiateViewController(withIdentifier: "childviewstoryboardid")
    self.addChildViewController(subview!)

    self.containerView.addSubview(subview!.view)
    subview?.didMove(toParentViewController: self)
    subview?.view.frame = self.containerView.frame

}

func unloadASubview(){
    subview?.willMove(toParentViewController: nil)
    subview?.view.removeFromSuperview()
    subview?.removeFromParentViewController()

}

Answer 3

这是我对autoLayout的决心。这是无需进行任何额外修改的最佳方法。

在Children View Controller中，通常可以使用此功能“ show（vc：UIViewController，sender：Any？）” 来显示viewController（如果具有navigationController，它将推送新的Controller ，也不展示它）

Swift 4.2

func setChild() {
    let vc = UIStoryboard(name: "YOUR_STORYBOARD_NAME", bundle: nil).instantiateViewController(withIdentifier: "YOUR_CHILD_ID")
    self.addChild(vc)
    // need to set translatesAutoresizingMaskIntoConstraints false to enable auto layout
    vc.view.translatesAutoresizingMaskIntoConstraints = false
    /// add subview to parent
    view.addSubview(vc.view)
    /// send subview to back for show other view in parent
    view.sendSubviewToBack(vc.view)
    /// call did move to parent to show current children
    vc.didMove(toParent: self)

    /// <---create auto layout with VFL--->
    let horiConstraints = NSLayoutConstraint.constraints(withVisualFormat: "H:|-0-[view]-0-|",
                                                        options: .alignAllCenterY,
                                                        metrics: nil,
                                                        views: ["view" : vc.view])
    let verticalConstraints = NSLayoutConstraint.constraints(withVisualFormat: "V:|-0-[view]-0-|",
                                                        options: .alignAllCenterX,
                                                        metrics: nil,
                                                        views: ["view" : vc.view])
    view.addConstraints(horiConstraints)
    view.addConstraints(verticalConstraints)
    view.layoutIfNeeded()
}

之后，您可以删除第一个孩子

func removeFirstChild() {
    children.first?.willMove(toParent: nil)
    children.first?.view.removeFromSuperview()
    children.first?.didMove(toParent: nil)
}

或从父母中删除所有孩子

func removeAllChild() {
    for child in children {
        child.willMove(toParent: nil)
        child.view.removeFromSuperview()
        child.didMove(toParent: nil)
    }
}

Object-C

- (void)setChild {
    UIViewController *vc = [[UIStoryboard storyboardWithName:@"YOUR_STORYBOARD_NAME" bundle:nil] instantiateViewControllerWithIdentifier:@"YOUR_CHILD_ID"];
    [self addChildViewController:vc];
    // need to set translatesAutoresizingMaskIntoConstraints false to enable auto layout
    vc.view.translatesAutoresizingMaskIntoConstraints = NO;
    /// add subview to parent
    [self.view addSubview:vc.view];
    /// send subview to back for show other view in parent
    [self.view sendSubviewToBack:vc.view];
    /// call did move to parent to show current children
    [vc didMoveToParentViewController:self];


    /// <---create auto layout with VFL--->
    NSArray<__kindof NSLayoutConstraint *> *horiConstraints;
    horiConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-0-[view]-0-|"options:NSLayoutAttributeCenterY
                                                          metrics:nil
                                                            views:@{@"view": vc.view}];
    NSArray<__kindof NSLayoutConstraint *> *verticalConstraints;
    verticalConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"V:|-0-[view]-0-|"
                                                              options:NSLayoutAttributeCenterX
                                                              metrics:nil
                                                                views:@{@"view": vc.view}];
    [self.view addConstraints:horiConstraints];
    [self.view addConstraints:verticalConstraints];
    [self.view layoutIfNeeded];
}

之后，您可以删除第一个孩子

- (void)removeFirstChild {
    UIViewController *child = self.childViewControllers.firstObject;
    [child willMoveToParentViewController:nil];
    [child.view removeFromSuperview];
    [child didMoveToParentViewController:nil];
}

或从父母中删除所有孩子

- (void)removeAllChild {
    for (UIViewController* child in self.childViewControllers) {
        [child willMoveToParentViewController:nil];
        [child.view removeFromSuperview];
        [child didMoveToParentViewController:nil];
    }
}

如何在子视图控制器中显示segue？

3 个答案: