问题
I have four pages in a UIPageViewController, and I'd like to hide the dots on the last page. I successfully made a function that gets called on the last page of the UIPageViewController. Basically, if the current view is the last one, it is called. But what do I put in that function to hide the dots temporarily?
I found this https://stackoverflow.com/a/32016614/5700898 but it doesn't help with what goes inside that function. The normal method (hiding page dots on all pages), is not what I need.
How can I hide the page indicator dots only on the last page of a UIPageViewController?
Edit: Here's my code as asked for.
import UIKit
class TutorialController: UIPageViewController {
let pageControl = UIPageControl.appearanceWhenContainedInInstancesOfClasses([])
var currentview = "0"
private func stylePageControl() {
pageControl.currentPageIndicatorTintColor = UIColor.lightGrayColor()
pageControl.pageIndicatorTintColor = UIColor.darkGrayColor()
pageControl.backgroundColor = UIColor.whiteColor()
}
private func hidePageControl() { // this should let us hide the dots on the fourth view, by changing color.
pageControl.backgroundColor = UIColor(red: 0.2980392157, green: 0.2980392157, blue: 0.2980392157, alpha: 1.0)
pageControl.currentPageIndicatorTintColor = UIColor(red: 0.2980392157, green: 0.2980392157, blue: 0.2980392157, alpha: 1.0)
pageControl.pageIndicatorTintColor = UIColor(red: 0.2980392157, green: 0.2980392157, blue: 0.2980392157, alpha: 1.0)
}
private(set) lazy var orderedViewControllers: [UIViewController] = {
return [self.newViewController("1"),
self.newViewController("2"),
self.newViewController("3"),
self.newViewController("4")]
}()
private func newViewController(number: String) -> UIViewController {
return UIStoryboard(name: "Main", bundle: nil) .
instantiateViewControllerWithIdentifier("Tutorial\(number)") // calls the next view controller.
}
override func viewDidLoad() {
super.viewDidLoad()
stylePageControl() // just changing the color, this works.
dataSource = self
if let firstViewController = orderedViewControllers.first {
setViewControllers([firstViewController],
direction: .Forward,
animated: true,
completion: nil)
}
}
}
// MARK: UIPageViewControllerDataSource
extension TutorialController: UIPageViewControllerDataSource {
func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
return orderedViewControllers.count
}
func presentationIndexForPageViewController(pageViewController: UIPageViewController) -> Int {
guard let firstViewController = viewControllers?.first,
firstViewControllerIndex = orderedViewControllers.indexOf(firstViewController) else {
return 0
}
return firstViewControllerIndex
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerBeforeViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let previousIndex = viewControllerIndex - 1
guard previousIndex >= 0 else {
return nil
}
guard orderedViewControllers.count > previousIndex else {
return nil
}
return orderedViewControllers[previousIndex]
}
func pageViewController(pageViewController: UIPageViewController,
viewControllerAfterViewController viewController: UIViewController) -> UIViewController? {
guard let viewControllerIndex = orderedViewControllers.indexOf(viewController) else {
return nil
}
let nextIndex = viewControllerIndex + 1
currentview = "\(nextIndex)"
print("now on tutorial slide \(currentview)")
if currentview == "4" { // this is called successfully when the fourth page comes into view.
print("we are now on the fourth slide; hiding the page dots...") // this successfully prints.
UIPageControl.appearanceWhenContainedInInstancesOfClasses([TutorialController.self]).hidden = true // this should hide the all page controller dots, but it just doesn't work.
pageControl.hidden = true // also should hide page controller dots, also doesn't work.
hidePageControl() // this should change the color of the page controller dots, but doesn't (note that this function works to change color when I call it on viewDidLoad, but that's not where I want it; it doesn't work here).
print(pageControl.hidden) // always prints false, even though I am trying to set it to true.
}
let orderedViewControllersCount = orderedViewControllers.count
guard orderedViewControllersCount != nextIndex else {
return nil
}
guard orderedViewControllersCount > nextIndex else {
return nil
}
return orderedViewControllers[nextIndex]
}
}
回答1:
use the UIPageViewControllerDelegate method:
let pageControl = UIPageControl()
func pageViewController(pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if (index == numberOfPages()-1){
pageControl.hidden = true
}else{
pageControl.hidden = false
}
}
回答2:
I found that you can't actually hide the page control as it just never works. But a bit of a hack is to add this to your code:
func pageViewController(pageViewController: UIPageViewController, willTransitionToViewControllers pendingViewControllers: [UIViewController]) {
if let lastVC = pendingViewControllers.last?.isKindOfClass(youLastViewController){
if lastVC == true {
for view in self.view.subviews {
if view is UIScrollView {
view.frame = UIScreen.mainScreen().bounds
} else if view is UIPageControl {
view.center.y = self.view.frame.height * 1.5
}
}
}else {
for view in self.view.subviews {
if view is UIScrollView {
view.frame = UIScreen.mainScreen().bounds
} else if view is UIPageControl {
view.center.y = self.view.frame.height * 0.92
}
}
}
}
}
}
This actually move the page control of the screen and the same as hiding it.
回答3:
here is the complete code of UIPageViewController to hide dots from last page it's work fine
first create class for UIViewController and add UIPageViewControllerDelegate , UIPageViewControllerDataSource
create outlet for pageControl
@IBOutlet weak var pageControl: UIPageControl!
create variable for uipagecontroller
var pageControllerContainer : UIPageViewController!
var pages = [UIViewController]()
var currentIndex : Int?
private var pendingIndex : Int?
private var lastIndex : Int?
in ViewDidLoad: add following lines :
let page1 : UIViewController! = self.storyboard?.instantiateViewController(withIdentifier: "YourFirstPageViewController") as! YourFirstPageViewController
let page2 : UIViewController! = self.storyboard?.instantiateViewController(withIdentifier: "YourSecondPageViewController") as! YourSecondPageViewController
let page3 : UIViewController! = self.storyboard?.instantiateViewController(withIdentifier: "YourThirdPageViewController") as! YourThirdPageViewController
pages.append(page1)
pages.append(page2)
pages.append(page3)
pageControllerContainer = UIPageViewController(transitionStyle: .scroll, navigationOrientation: .horizontal, options: nil)
pageControllerContainer.delegate = self
pageControllerContainer.dataSource = self
pageControllerContainer.setViewControllers([page1], direction: .forward, animated: true, completion: nil)
view.addSubview(pageControllerContainer.view)
view.bringSubview(toFront: pageControl)
pageControl.numberOfPages = pages.count
pageControl.currentPage = 0
now create following delegates method for pageviewcontroller:
func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
let currentIndex = pages.index(of: viewController)
if currentIndex == 0
{
return nil
}
let previousIndex = abs((currentIndex! - 1) % pages.count)
return pages[previousIndex]
}
func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
let currentIndex = pages.index(of: viewController)
if currentIndex == pages.count - 1
{
return nil
}
let nextIndex = abs((currentIndex! + 1 ) % pages.count)
return pages[nextIndex]
}
after that create following datasource methods
func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
pendingIndex = pages.index(of: pendingViewControllers.first!)
}
func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
if completed
{
currentIndex = pendingIndex
if let index = currentIndex
{
pageControl.currentPage = index
}
}
lastIndex = pages.count - 1
print(lastIndex as Any)
print(currentIndex as Any)
if currentIndex == lastIndex
{
pageControl.isHidden = true
}
else
{
pageControl.isHidden = false
}
}
this will allows to hide page controller when it comes to last index means last page
hope this will help :-) thank you ...
回答4:
override func presentationCountForPageViewController(pageViewController: UIPageViewController) -> Int {
if /*current index is the last one*/ {
return 0
} else {
/*return number of pages*/
}
}
回答5:
Check out the accepted answer here to get the UIPageControl (the view with the dots):
Access the UIPageControl created by iOS6 UIPageViewController?
Then, once you have the pageControl, in pageViewController: didFinishAnimating: you can check if it's the last page, and if so set pageControl.hidden = true.
来源：https://stackoverflow.com/questions/36391401/hide-dots-on-final-page-of-uipageviewcontroller-swift