Iphone 如何使带有UIPageViewController点的底部栏半透明？

我正在制作一个教程，我试图模仿Path教程的风格，如下所示：

我的问题是，如果将委托方法设置为：

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    // The number of items reflected in the page indicator.
    return 5;
}

然后我在圆点下面画了一条愚蠢的黑条：

---

是否有一种方法可以使此栏半透明，其方式类似于将UINavigationBar设置为半透明？

我认为您无法更改UIPageViewController的行为，因此路径应用程序可能使用自己的视图控制器。您也可以这样做：创建自己的容器视图控制器，该控制器使用UIPageControl来指示当前页面。

使其工作起来非常容易。只需将pageviewcontroller设置得更高，并将PageControl放置到XIB文件中即可。 诀窍是在开始时将PageControl（以及所有其他常用控件）放在前台，并使用PageViewController更新PageControl的内容。代码如下：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    self.pageController = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];

    self.pageController.dataSource = self;
    // We need to cover all the control by making the frame taller (+ 37)
    [[self.pageController view] setFrame:CGRectMake(0, 0, [[self view] bounds].size.width, [[self view] bounds].size.height + 37)];

    TutorialPageViewController *initialViewController = [self viewControllerAtIndex:0];

    NSArray *viewControllers = [NSArray arrayWithObject:initialViewController];

    [self.pageController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];

    [self addChildViewController:self.pageController];
    [[self view] addSubview:[self.pageController view]];
    [self.pageController didMoveToParentViewController:self];

    // Bring the common controls to the foreground (they were hidden since the frame is taller)
    [self.view bringSubviewToFront:self.pcDots];
    [self.view bringSubviewToFront:self.btnSkip];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController {

    NSUInteger index = [(TutorialPageViewController *)viewController index];

    [self.pcDots setCurrentPage:index];

    if (index == 0) {
        return nil;
    }

    index--;

    return [self viewControllerAtIndex:index];
}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController {

    NSUInteger index = [(TutorialPageViewController *)viewController index];

    [self.pcDots setCurrentPage:index];

    index++;

    if (index == 3) {
        return nil;
    }

    return [self viewControllerAtIndex:index];
}

- (TutorialPageViewController *)viewControllerAtIndex:(NSUInteger)index {

    TutorialPageViewController *childViewController = [[TutorialPageViewController alloc] initWithNibName:@"TutorialPageViewController" bundle:nil];
    childViewController.index = index;

    return childViewController;
}

- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController {
    // The number of items reflected in the page indicator.
    NSInteger tutorialSteps = 3;
    [self.pcDots setNumberOfPages:tutorialSteps];

    return tutorialSteps;
}

- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController {
    // The selected item reflected in the page indicator.
    return 0;
}

---

您可以简单地调整UIPageViewController的UIPageControl的alpha

首先，您应该从UIPageViewController中检索它，如下所示：

- (UIPageControl *)getPageControlForPageViewController:(UIPageViewController *)pageViewController {
      for (UIView *subview in self.pageViewController.view.subviews) {
        if ([subview isKindOfClass:[UIPageControl class]]) {
          return (UIPageControl *) subview;
        }
      }

      return nil;
    }

接下来，使用该函数。我在ViewController上创建了一个名为childPageControl的属性。将UIPageViewController的UIPageControl指定给它：

self.childPageControl = [self getPageControlForPageViewController:self.pageViewController];

接下来，可以调整alpha以提供半透明效果：

self.childPageControl.alpha = .5;

---

要影响UIPageViewController的UIPageControl，您所能做的非常有限，但您至少可以轻松实现这一点。

只需将UIPageViewController子类化并覆盖ViewDidLayoutSubview，即可实现相同的效果，如下所示：

-(void)viewDidLayoutSubviews {
    UIView* v = self.view;
    NSArray* subviews = v.subviews;
    // Confirm that the view has the exact expected structure.
    // If you add any custom subviews, you will want to remove this check.
    if( [subviews count] == 2 ) {
        UIScrollView* sv = nil;
        UIPageControl* pc = nil;
        for( UIView* t in subviews ) {
            if( [t isKindOfClass:[UIScrollView class]] ) {
                sv = (UIScrollView*)t;
            } else if( [t isKindOfClass:[UIPageControl class]] ) {
                pc = (UIPageControl*)t;
            }
        }
        if( sv != nil && pc != nil ) {
            // expand scroll view to fit entire view
            sv.frame = v.bounds;
            // put page control in front
            [v bringSubviewToFront:pc];
        }
    }
    [super viewDidLayoutSubviews];
}

---

这样就不需要维护单独的UIPageControl等。

我找到了另一个更适合我的工作区

我重用以获取UIPageControl（称为pageControl的变量）和UIPageViewController使用的UIScrollView（称为pageView的变量）

一旦在viewDidLoad中完成了这项操作，我就阻止了pageView的clip子视图，并让内容传播到UIPageControl之下

pageControl位于pageView下方，因此我们必须手动将其置于前面

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    if(
       [[[self view] subviews] count] == 2
       )
    {
        UIScrollView* pageView = nil;
        UIPageControl* pageControl = nil;

        UIView* selfView = self.view;
        NSArray* subviews = selfView.subviews;

        for( NSInteger i = 0 ; i < subviews.count && ( pageView == nil || pageControl == nil ) ; i++ )
        {
            UIView* t = subviews[i];
            if( [t isKindOfClass:[UIScrollView class]] )
            {
                pageView = (UIScrollView*)t;
            }
            else if( [t isKindOfClass:[UIPageControl class]] )
            {
                pageControl = (UIPageControl*)t;
            }
        }

        if( pageView != nil && pageControl != nil )
        {
            [pageView setClipsToBounds:NO];
            [selfView bringSubviewToFront:pageControl];
        }
    }
}

-（void）viewDidLoad
{
[超级视图下载]；
//加载视图后执行任何其他设置。
如果(
[[[self view]子视图]计数]==2
)
{
UIScrollView*pageView=nil；
UIPageControl*pageControl=nil；
UIView*selfView=self.view；
NSArray*子视图=selfView.subview；
对于（NSInteger i=0；i

一旦我的pageView覆盖了pageControl占用的空间，但在pageControl下，我只需调整显示为page的每个viewController的nib文件使用：

• 基础视图不应剪裁
• 第一个也是唯一的子视图：
  • 应具有从superview底部将底部设置为-37的约束（如果需要，可以设置为更多，但37是页面控件的大小）
  • 应该剪辑内容吗

---

我想在我正在开发的应用程序中实现类似的效果-我使用了一个带有单独UIPageControl的UIPageViewController

这使您可以将UIPageControl放置在视图中希望的任何位置，包括UIPageViewController顶部，并通过UIPageViewController委托方法使其活动页面点保持最新：

- (void)pageViewController:(UIPageViewController *)pageViewController
        didFinishAnimating:(BOOL)finished
   previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers
       transitionCompleted:(BOOL)completed {
    if (completed) {
        self.pageControl.currentPage = [self.pageViewControllers indexOfObject:pageViewController.viewControllers.firstObject];
    }
}

-（无效）pageViewController:（UIPageViewController*）pageViewController
完成了
PreviousViewController:（NSArray*）PreviousViewController
过渡已完成：（BOOL）已完成{
如果（已完成）{
self.pageControl.currentPage=[self.pageViewController索引对象：pageViewController.ViewController.firstObject]；
}
}

无需遍历子视图层次结构来查找内部UIPageViewController页面控件，也无需调整内部scrollview内容的大小

---

希望这能有所帮助。

我今天发现的小黑客

请参阅下面的代码

self.pageController.dataSource=self；
CGRect rect=[self.view bounds]；
矩形尺寸高度+=37；
[[self.pageController view]setFrame:rect]；
NSArray*子视图=self.pageController.view.subview；
UIPageControl*thisControl=nil；
对于（int i=0；i这里是Zerotool的解决方案到Swift 2.1的转换，尽管可能有一种更优雅的方式来编写它：

override func viewDidLayoutSubviews() {
    var scrollView: UIScrollView?
    var pageControl: UIPageControl?

    // If you add any custom subviews, you will want to remove this check.
    if (self.view.subviews.count == 2) {
        for view in self.view.subviews {
            if (view.isKindOfClass(UIScrollView)) {
                scrollView = view as? UIScrollView
            } else if (view.isKindOfClass(UIPageControl)) {
                pageControl = view as? UIPageControl
            }
        }
    }

    if let scrollView = scrollView {
        if let pageControl = pageControl {
            scrollView.frame = self.view.bounds
            self.view.bringSubviewToFront(pageControl)
        }
    }

    super.viewDidLayoutSubviews()
}

这个代码是用Swift写的
在UIPageViewController中添加以下内容

override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()

    for view in self.view.subviews {
        if view.isKindOfClass(UIScrollView) {
            view.frame = UIScreen.mainScreen().bounds
        } else if view.isKindOfClass(UIPageControl) {
            view.backgroundColor = UIColor.clearColor()
        }
    }
}

Swift 3片段

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let scrollView = view.subviews.filter({ $0 is UIScrollView }).first,
        let pageControl = view.subviews.filter({ $0 is UIPageControl }).first {
        scrollView.frame = view.bounds
        view.bringSubview(toFront:pageControl)
    }
}

我使用以下代码进行求解：

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.


self.namesImage = @[@"page1.png", @"page2.png", @"page3.png", @"page4.png"];

self.pageViewController = [self.storyboard instantiateViewControllerWithIdentifier:@"PageViewController"];
self.pageViewController.dataSource = self;


TutorialContentViewController *startingViewController = [self viewControllerAtIndex:0];
NSArray *viewControllers = @[startingViewController];

[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];


[self addChildViewController:self.pageViewController];
[self.view addSubview:self.pageViewController.view];
[self.pageViewController didMoveToParentViewController:self];

[[UIPageControl appearance] setPageIndicatorTintColor:[UIColor grayColor]];
[[UIPageControl appearance] setCurrentPageIndicatorTintColor:[UIColor whiteColor]];
[[UIPageControl appearance] setBackgroundColor: [[UIColor blackColor] colorWithAlphaComponent:0.1f]];
[[UIPageControl appearance] setOpaque:YES];

}

Swift 5.2

您可以根据需要使用此代码

 override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let myScrollView = view.subviews.filter({ $0 is UIScrollView }).first,
        let myPageControl = view.subviews.filter({ $0 is UIPageControl }).first {
        myScrollView.frame = view.bounds
        view.bringSubviewToFront(myPageControl)
    }
}

@MikeV如果你想要框架缺少的功能，向苹果提交一份bug报告是没有坏处的。很好，我可能会这么做。与此同时，我似乎在重写代码来解释这一点。我很惊讶。我在我的基本实用程序应用程序上使用了UiPageControl，默认情况下它是透明的。@Robvandervier问题并不是真正的问题控件的重要性，是由UIPageViewController管理的视图的大小以及UIPageControl在黑色背景上的位置。这不太好。只需转到第一页或最后一页，向无法转到的方向滚动，然后看着索引被抛出。@AdamPro13我同意，这对我也不起作用。我通过实现
UIPageViewController使其正常工作
 override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    if let myScrollView = view.subviews.filter({ $0 is UIScrollView }).first,
        let myPageControl = view.subviews.filter({ $0 is UIPageControl }).first {
        myScrollView.frame = view.bounds
        view.bringSubviewToFront(myPageControl)
    }
}