我有一个简单的UIPageViewController，它在页面底部显示默认的UIPageControl。我想知道是否可以修改UIPageControl的位置，例如位于屏幕顶部而不是底部。 我一直在环顾四周，只发现旧的讨论说我需要创建自己的UIPageControl。 这对iOS8和9来说更简单吗？ 谢谢。
答案 0 :(得分：34)
是的，您可以为此添加自定义页面控制器。
self.pageControl = [[UIPageControl alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height - 50, self.view.frame.size.width, 50)]; // your position
[self.view addSubview: self.pageControl];
然后删除
- (NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController
和
- (NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController
然后添加另一个委托方法：
- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers
{
PageContentViewController *pageContentView = (PageContentViewController*) pendingViewControllers[0];
self.pageControl.currentPage = pageContentView.pageIndex;
}
答案 1 :(得分：8)
覆盖pageviewcontroller的viewDidLayoutSubviews（）并使用此
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
// get pageControl and scroll view from view's subviews
let pageControl = view.subviews.filter{ $0 is UIPageControl }.first! as! UIPageControl
let scrollView = view.subviews.filter{ $0 is UIScrollView }.first! as! UIScrollView
// remove all constraint from view that are tied to pagecontrol
let const = view.constraints.filter { $0.firstItem as? NSObject == pageControl || $0.secondItem as? NSObject == pageControl }
view.removeConstraints(const)
// customize pagecontroll
pageControl.translatesAutoresizingMaskIntoConstraints = false
pageControl.addConstraint(pageControl.heightAnchor.constraintEqualToConstant(35))
pageControl.backgroundColor = view.backgroundColor
// create constraints for pagecontrol
let leading = pageControl.leadingAnchor.constraintEqualToAnchor(view.leadingAnchor)
let trailing = pageControl.trailingAnchor.constraintEqualToAnchor(view.trailingAnchor)
let bottom = pageControl.bottomAnchor.constraintEqualToAnchor(scrollView.topAnchor, constant:8) // add to scrollview not view
// pagecontrol constraint to view
view.addConstraints([leading, trailing, bottom])
view.bounds.origin.y -= pageControl.bounds.maxY
}
答案 2 :(得分：7)
Shameerjan的答案非常好，但是还需要一件事才能正常工作，那就是另一个委托方法的实现：
func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
// If user bailed our early from the gesture,
// we have to revert page control to previous position
if !completed {
let pageContentView = previousViewControllers[0] as! PageContentViewController;
self.pageControl.currentPage = pageContentView.pageIndex;
}
}
这是因为如果您没有，如果您稍微移动页面控件，它将返回到上一个位置 - 但页面控件将显示不同的页面。
希望它有所帮助！
答案 3 :(得分：7)
只需在PageViewController子类中查找PageControl并设置框架，位置或任何你想要的内容
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
for subView in view.subviews {
if subView is UIPageControl {
subView.frame.origin.y = self.view.frame.size.height - 164
}
}
}
答案 4 :(得分：3)
是的，Shameerjan的答案非常好，但不是添加其他页面控件，而是可以使用默认页面指示器：
- (UIPageControl*)pageControl {
for (UIView* view in self.view.subviews) {
if ([view isKindOfClass:[UIPageControl class]]) {
//set new pageControl position
view.frame = CGRectMake( 100, 200, width, height);
return (id)view;
}
}
return nil;
}
然后扩展UIPageViewController的大小以掩盖底部差距：
//somewhere in your code
self.view.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height+40);
答案 5 :(得分：3)
Swift 4版：
首先，您创建自定义pageControl：
let pageControl = UIPageControl()
您可以将其添加到视图中并根据需要进行定位：
self.view.addSubview(self.pageControl)
self.pageControl.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
self.pageControl.leftAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.leftAnchor, constant: 43),
self.pageControl.bottomAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.bottomAnchor, constant: -33)
])
然后您需要初始化pageControl：
self.pageControl.numberOfPages = self.dataSource.controllers.count
最后，您需要实施UIPageViewControllerDelegate及其方法pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:)：
func pageViewController(_ pageViewController: UIPageViewController,
didFinishAnimating finished: Bool,
previousViewControllers: [UIViewController],
transitionCompleted completed: Bool) {
// this will get you currently presented view controller
guard let selectedVC = pageViewController.viewControllers?.first else { return }
// and its index in the dataSource's controllers (I'm using force unwrap, since in my case pageViewController contains only view controllers from my dataSource)
let selectedIndex = self.dataSource.controllers.index(of: selectedVC)!
// and we update the current page in pageControl
self.pageControl.currentPage = selectedIndex
}
现在与@ Jan的答案相比，我们使用self.pageControl.currentPage（如上所示）更新pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:)，而不是pageViewController(_:willTransitionTo:)。这克服了取消转换的问题 - 在转换完成时始终调用pageViewController(_:didFinishAnimating:previousViewControllers:transitionCompleted:)（它也更好地模仿标准页面控制的行为）。
最后，要删除标准页面控件，请务必删除presentationCount(for:)的{{1}}和presentationIndex(for:)方法的实现 - 如果方法已实现，则标准页面控件将是呈现。
所以，你不希望在你的代码中有这个：
UIPageViewControllerDataSource答案 6 :(得分：2)
对于swift：
self.pageController = UIPageControl(
frame: CGRect(
x: 0,
y: self.view.frame.size.height - 50,
width: self.view.frame.size.width,
height: 50
)
)
self.view.addSubview(pageController)
记得使用pageController.numberOfPages并委托pageView
然后删除
func presentationCountForPageViewController(
pageViewController: UIPageViewController
) -> Int
和
func presentationIndexForPageViewController(
pageViewController: UIPageViewController
) -> Int
然后添加另一个委托方法：
func pageViewController(
pageViewController: UIPageViewController,
willTransitionToViewControllers pendingViewControllers:[UIViewController]){
if let itemController = pendingViewControllers[0] as? PageContentViewController {
self.pageController.currentPage = itemController.pageIndex
}
}
}
答案 7 :(得分：2)
这是一个非常有效的方法来更改PageViewController的默认PageControl的位置，而无需创建新的... ...
extension UIPageViewController {
override open func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
for subV in self.view.subviews {
if type(of: subV).description() == "UIPageControl" {
let pos = CGPoint(x: subV.frame.origin.x, y: subV.frame.origin.y - 75 * 2)
subV.frame = CGRect(origin: pos, size: subV.frame.size)
}
}
}
}
答案 8 :(得分：1)
这是我的看法。此版本仅在动画结束时更改de指示符，即当您到达目标页面时。
/** Each page you add to the UIPageViewController holds its index */
class Page: UIViewController {
var pageIndex = 0
}
class MyPageController : UIPageViewController {
private let pc = UIPageControl()
private var pendingPageIndex = 0
// ... add pc to your view, and add Pages ...
/** Will transition, so keep the page where it goes */
func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController])
{
let controller = pendingViewControllers[0] as! Page
pendingPageIndex = controller.pageIndex
}
/** Did finish the transition, so set the page where was going */
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool)
{
if (completed) {
pc.currentPage = pendingPageIndex
}
}
}
答案 9 :(得分：0)
This is good, and with more change
var pendingIndex = 0;
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if completed {
pageControl.currentPage = pendingIndex
}
}
func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
let itemController = pendingViewControllers.first as! IntroPageItemViewController
pendingIndex = itemController.itemIndex
}
答案 10 :(得分：0)
确保将pageControl添加为子视图。 然后在
UserID='$_SESSION['currentUserID']'答案 11 :(得分：0)
override func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
for view in self.view.subviews{
if view is UIScrollView{
view.frame = UIScreen.main.bounds
}
else if view is UIPageControl {
view.backgroundColor = UIColor.clear
view.frame.origin.y = self.view.frame.size.height - 75
}
}
}
答案 12 :(得分：0)
下面的示例使用自定义的UIPageControl，它位于UIPageViewController的底部中心位置。要使用该代码，请将MemberProfilePhotoViewController替换为您用作页面的视图控制器类型。
numberOfPages上设置pageControl属性。pageControl的大小，可以使用pageControl.size(forNumberOfPages: count)。presentationCount(...)和presentationIndex(...)以删除默认页面控件。UIPageViewControllerDelegate的{{1}}似乎是更新didFinishAnimating的更好时机。pageControl.currentPage答案 13 :(得分：-1)
只需获取第一个视图控制器并找出didFinishAnimating中的索引：
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
pageControl.currentPage = onboardingViewControllers.index(of: pageViewController.viewControllers!.first!)!
}