我正在制作教程，我正在尝试模仿 Path 教程的风格，如下所示：
http://www.appcoda.com/wp-content/uploads/2013/06/UIPageViewController-Tutorial-Screen.jpg
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;
}
然后我在点下得到这个愚蠢的黑条：
http://i.stack.imgur.com/pUEdh.png
有没有办法以类似于将 UINavigationBar 设置为半透明的方式使该栏半透明？
让它工作很容易。您只需要使 pageviewcontroller 更高，并将 PageControl 放入 XIB 文件中。诀窍是一开始就把 PageControl 放在前台（以及所有其他常用控件），然后用 PageViewController 更新 PageControl 的内容。这是代码：
- (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;
}
只需继承 UIPageViewController 并覆盖 viewDidLayoutSubviews 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];
}
那么就没有必要维护一个单独的 UIPageControl 之类的了。
斯威夫特 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)
}
}
这是 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()
}
我认为您无法更改 UIPageViewController 的行为，因此 Path 应用程序似乎很可能使用自己的视图控制器。您也可以这样做：创建您自己的容器视图控制器，该控制器使用 UIPageControl 来指示当前页面。
您可以简单地调整 UIPageViewController 的 UIPageControl 的 alpha。
首先，您应该像这样从 UIPageViewController 中检索它：
- (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，使用该功能。我在 ViewController 上创建了一个名为 childPageControl 的属性。给它 UIPageViewController 的 UIPageControl：
self.childPageControl = [self getPageControlForPageViewController:self.pageViewController];
接下来，您可以调整 alpha 以提供半透明效果：
self.childPageControl.alpha = .5;
您在影响 UIPageViewController 的 UIPageControl 方面可以做的事情非常有限，但您至少可以轻松实现这一点。
此代码在 Swift 在您的 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()
}
}
}
我今天发现的小技巧..
请看下面的代码。
self.pageController.dataSource = self;
CGRect rect = [self.view bounds];
rect.size.height+=37;
[[self.pageController view] setFrame:rect];
NSArray *subviews = self.pageController.view.subviews;
UIPageControl *thisControl = nil;
for (int i=0; i<[subviews count]; i++) {
if ([[subviews objectAtIndex:i] isKindOfClass:[UIPageControl class]]) {
thisControl = (UIPageControl *)[subviews objectAtIndex:i];
}
}
UIView *tempview = [[UIView alloc] initWithFrame:CGRectMake(0, -30, 320, 40)];
[tempview addSubview:thisControl];
thisControl.pageIndicatorTintColor = [UIColor lightGrayColor];
thisControl.currentPageIndicatorTintColor = [UIColor greenColor];
[self.view addSubview:tempview];
我使用以下代码解决：
- (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];
}
斯威夫特 5.2
您可以将此代码用于您的要求
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)
}
}
我想在我正在开发的应用程序中做类似的效果——我使用了一个 UIPageViewController 和一个单独的 UIPageControl。
这使您可以将 UIPageControl 放置在视图中您想要的任何位置，包括 UIPageViewController 的顶部，并通过 UIPageViewController 委托方法保持其活动页面点为最新：
- (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];
}
}
无需遍历子视图层次结构试图找到内部的 UIPageViewController 页面控件，也不必调整内部滚动视图的内容大小。
希望这可以帮助。
我找到了另一个更适合我的解决方法。
我重用zerotool 给出的代码来获取 UIPageViewController 使用的 UIPageControl（称为 pageControl 的变量）和 UIScrollView（称为 pageView 的变量）。
一旦在 viewDidLoad 中完成，我将阻止 pageView 的剪辑子视图，并让内容更多地传播到 UIPageControl 下方。
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];
}
}
}
一旦我的 pageView 覆盖了 pageControl 但在 pageControl 下占用的空间，我只需要调整显示为 page 的每个 viewController 的 nib 文件使用：