如何以编程方式在 UIStackView 中添加响应式 UIPageViewController？

Question

我试图将 UIPageViewController 放在没有预定高度的 UIView 中。 我想要实现的是构建一个响应式应用内消息，它具有一个或多个组件（按钮、文本、轮播等），其高度由其子项决定。

模态窗口适用于除 UIPageViewController 之外的所有组件。 UIView 会根据我放入的任何组件调整大小，但不会在我放置 UIPageViewController 时调整大小。 似乎缺少一些约束。

一般的层次结构是：

UIView (centered vertically on the screen with trailing and leading margins, no height)
|  UIStackView (inside this UIStackView I place any number of components I wish)
|  |  UILabel (example component)
|  |  UIButton (example component)
|  |  UIPageViewController (example component)
|  |  |  UIStackView (inside this UIStackView I place any other number of components)
|  |  |  |  UILabel (example component)
|  |  |  |  UIButton (example component)
…

以下日志摘录属于具有以下特征的应用内消息：

UIView (centered vertically on the screen with trailing and leading margins, no height)
|  UIStackView (leading and trailing anchors equal to parent, top and bottom anchors equal to children)
|  |  UIPageViewController (will display bellow the first slide content)
|  |  |  UIStackView
|  |  |  |  UIImageView
|  |  |  |  UILabel
|  |  |  |  UILabel

日志：

(lldb) po [[0x7feeb7a78e30 superview ] recursiveDescription]
<UIView: 0x7feeb76c44f0; frame = (0 0; 334 0); layer = <CALayer: 0x600002afd1c0>>
   | <_UIPageViewControllerContentView: 0x7feeb7a78e30; frame = (0 0; 334 0); clipsToBounds = YES; opaque = NO; autoresize = W+H; layer = <CALayer: 0x600002ae1500>>
   |    | <_UIQueuingScrollView: 0x7feeafbc6800; frame = (0 0; 334 0); clipsToBounds = YES; gestureRecognizers = <NSArray: 0x600002773600>; layer = <CALayer: 0x600002ae0e80>; contentOffset: {334, 0}; contentSize: {1002, 0}; adjustedContentInset: {0, -334, 0, -334}>
   |    |    | <UIView: 0x7feeb7a79b30; frame = (0 0; 334 0); layer = <CALayer: 0x600002ae04a0>>
   |    |    | <UIView: 0x7feeb7a79ca0; frame = (334 0; 334 0); layer = <CALayer: 0x600002ae0880>>
   |    |    |    | <UIView: 0x7feeb6f25990; frame = (0 0; 757 219.667); autoresize = W+H; layer = <CALayer: 0x600002aed700>>
   |    |    |    |    | <UIStackView: 0x7feeb6fb7a10; frame = (0 0; 757 219.667); layer = <CALayer: 0x600002aed8c0>>
   |    |    |    |    |    | <UIImageView: 0x7feeb76ceb70; frame = (0 0; 757 131.667); clipsToBounds = YES; opaque = NO; userInteractionEnabled = NO; layer = <CALayer: 0x600002aff560>>
   |    |    |    |    |    | <UILabel: 0x7feeb76ced40; frame = (0 141.667; 757 29.6667); text = 'This is the first slide t...'; userInteractionEnabled = NO; layer = <_UILabelLayer: 0x600000bddb30>>
   |    |    |    |    |    | <UILabel: 0x7feeb6fb7c60; frame = (0 181.333; 757 18.3333); text = 'This is the description f...'; userInteractionEnabled = NO; layer = <_UILabelLayer: 0x600000bca0d0>>
   |    |    | <UIView: 0x7feeb7a79e10; frame = (668 0; 334 0); layer = <CALayer: 0x600002ae0840>>
   |    | <UIPageControl: 0x7feeb76cb9b0; frame = (10 -25; 314 20); autoresize = W; userInteractionEnabled = NO; gestureRecognizers = <NSArray: 0x600002693180>; layer = <CALayer: 0x600002afdac0>>
   |    |    | <_UIPageControlContentView: 0x7feeb6fb4b10; frame = (111.667 -3; 91 26); layer = <CALayer: 0x600002aed0c0>>
   |    |    |    | <_UIPageControlIndicatorContentView: 0x7feeb6fb73b0; frame = (14.3333 0; 62.6667 26); autoresize = H; layer = <CALayer: 0x600002aec080>>
   |    |    |    |    | <_UIPageIndicatorView: 0x7feeb6f27570; frame = (0.166667 8.16667; 9.66667 9.66667); opaque = NO; userInteractionEnabled = NO; tintColor = UIExtendedGrayColorSpace 0.333333 1; layer = <CALayer: 0x600002ae5b00>>
   |    |    |    |    | <_UIPageIndicatorView: 0x7feeb0809630; frame = (17.5 8.16667; 9.66667 9.66667); opaque = NO; userInteractionEnabled = NO; tintColor = UIExtendedGrayColorSpace 0.666667 1; layer = <CALayer: 0x600002a01000>>
   |    |    |    |    | <_UIPageIndicatorView: 0x7feeb6cd34c0; frame = (35.5 8.16667; 9.66667 9.66667); opaque = NO; userInteractionEnabled = NO; tintColor = UIExtendedGrayColorSpace 0.666667 1; layer = <CALayer: 0x600002a01080>>
   |    |    |    |    | <_UIPageIndicatorView: 0x7feeb6fc6100; frame = (53.1667 8.16667; 9.66667 9.66667); opaque = NO; userInteractionEnabled = NO; tintColor = UIExtendedGrayColorSpace 0.666667 1; layer = <CALayer: 0x600002ae0140>>

这里有两个例子。 第一个是没有 UIPageViewController 的有效应用内消息。 第二个是我想要实现的目标，但作为 Android 上的一个工作示例。

在没有 UIPageViewController 的情况下工作应用内消息 Android 上的轮播工作示例

基于这些日志，有人能指出我纠正约束的正确方向吗？ 发生的情况是层次结构中较高的视图具有 0 高度，但它们的子视图没有。 这会导致 0 高度的应用内消息。

编辑

我将模态视图作为子视图添加到主视图中，当 UIPageViewController 出现在层次结构中时，我将它添加到顶部控制器：

一切都是通过代码完成的。 我没有添加视图控制器，只是在主视图中添加子视图：

UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
if (keyWindow != nil) {
    [keyWindow addSubview:self.parentView]; // self.parentView = blackish background + vertically centered UIView (the actual modal view) + UIStackView for the components
    if (hasCarousel){
        UIViewController *topController = [UIApplication getPresentedViewController];
        if (topController != nil)
            [topController embedViewController:pageViewController inView:carouselWrapper]; // carouselWrapper = UIView containing the pageViewController that is added to the UIStackView above

    }
}

Answer 1

根据我们的评论提供答案...

UIPageViewController加载并设置其“页面”控制器的视图大小。 因此，尝试以相反的方式进行 - 设置页面视图控制器的大小以匹配“页面”大小有点棘手。

此外，如果我们尝试为每个“页面”都这样做，框架会不断变化，并且（可能）会带来糟糕的用户体验。

但是，我们可以预加载页面并计算最大页面高度以设置我们的控制器。

概述代码将是：

MutableArray *pages = [NSMutableArray new];
// however we load and initialize our page controllers
[pages addObject:FirstPageVC()];
[pages addObject:SecondPageVC()];
// etc

CGFloat maxHeight = 0;

CGSize fitSize = CGSizeMake(_carouselWrapper.frame.size.width, UILayoutFittingCompressedSize.height);

for (UIViewController *vc in pages) {
    // get size of page view
    CGSize sz = [vc.view systemLayoutSizeFittingSize:fitSize withHorizontalFittingPriority:UILayoutPriorityRequired verticalFittingPriority:UILayoutPriorityDefaultLow];
    maxHeight = MAX(sz.height, maxHeight);
}

// if using the built-in PageControl
//  add height of PageControl + 1.5 (control is shown 1.5-pts below the view)
UIPageControl *c = [UIPageControl new];
maxHeight += [c sizeForNumberOfPages:1].height + 1.5;

// here we can set the height of the view frame for our PageViewController

我玩了一下，在这里放了一个工作示例项目： https : //github.com/DonMag/DynamicPGVC

您展示的内容的基本思想，尽管我将“parentView”（我称之为 OverlayView）作为一个单独的视图子类，以将大量活动排除在主视图控制器之外。

这是它的外观：