在 UIPageViewController
中,是否可以通过编程的方式翻页?
在 UIPageViewController
中,是否可以通过编程的方式翻页?
//Set Delegate & Data Source for PageView controller [Say in View Did Load]
self.pageViewController.dataSource = self;
self.pageViewController.delegate = self;
// Delegates called viewControllerBeforeViewController when User Scroll to previous page
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController *)viewController{
[_nextBtn setTitle:@"Next" forState:UIControlStateNormal];
NSUInteger index = ((PageContentViewController*) viewController).pageIndex;
if (index == NSNotFound){
return nil;
}else if (index > 0){
index--;
}else{
return nil;
}
return [self viewControllerAtIndex:index];
}
// 当用户滚动到下一页时,委托调用viewControllerAfterViewController
- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
NSUInteger index = ((PageContentViewController*) viewController).pageIndex;
if (index == NSNotFound){
return nil;
}else if (index < 3){
index++;
}else{
return nil;
}
return [self viewControllerAtIndex:index];}
//Delegate called while transition of pages. The need to apply logic in this delegate is to maintain the index of current page.
- (void)pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray *)pendingViewControllers{
buttonIndex = (int)((PageContentViewController*) pendingViewControllers.firstObject).pageIndex;
}
-(void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray *)previousViewControllers transitionCompleted:(BOOL)completed{
if (buttonIndex == 0){
_backButton.hidden = true;
}else if (buttonIndex == [self.pageImages count] - 1){
_backButton.hidden = false;
[_nextBtn setTitle:@"Begin" forState:UIControlStateNormal];
}else{
_backButton.hidden = false;
}
//自定义按钮(上一步和下一步)的逻辑
-(void)backBtnClicked:(id)sender{
if (buttonIndex > 0){
buttonIndex -= 1;
}
if (buttonIndex < 1) {
_backButton.hidden = YES;
}
if (buttonIndex >=0) {
[_nextBtn setTitle:@"Next" forState:UIControlStateNormal];
PageContentViewController *startingViewController = [self viewControllerAtIndex:buttonIndex];
NSArray *viewControllers = @[startingViewController];
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
}
}
-(void)nextBtnClicked:(id)sender{
if (buttonIndex < 3){
buttonIndex += 1;
}
if(buttonIndex == _pageImages.count){
//Navigate Outside Pageview controller
}else{
if (buttonIndex ==3) {
[_nextBtn setTitle:@"Begin" forState:UIControlStateNormal];
}
_backButton.hidden = NO;
PageContentViewController *startingViewController = [self viewControllerAtIndex:buttonIndex];
NSArray *viewControllers = @[startingViewController];
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:NO completion:nil];
}
}
//BUTTON INDEX & MAX COUNT
-(NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController{
return [self.pageImages count];}
-(NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController{
return buttonIndex;}
我还需要一个用于在PageViewController中向左导航的按钮,这个按钮应该执行与滑动手势相同的操作。
由于我已经在“pageViewController:viewControllerBeforeViewController”中设置了一些规则以处理自然滑动导航,因此我希望该按钮重用所有该代码,并且不能像之前的答案那样使用特定的索引来达到页面。所以,我必须采取另一种解决方案。
请注意,以下代码适用于我的自定义ViewController内部的一个Page View Controller,其脊柱设置为中间。
这是我为导航左侧按钮编写的代码:
- (IBAction)btnNavigateLeft_Click:(id)sender {
// Calling the PageViewController to obtain the current left page
UIViewController *currentLeftPage = [_pageController.viewControllers objectAtIndex:0];
// Creating future pages to be displayed
NSArray *newDisplayedPages = nil;
UIViewController *newRightPage = nil;
UIViewController *newLeftPage = nil;
// Calling the delegate to obtain previous pages
// My "pageViewController:viewControllerBeforeViewController" method returns nil if there is no such page (first page of the book).
newRightPage = [self pageViewController:_pageController viewControllerBeforeViewController:currentLeftPage];
if (newRightPage) {
newLeftPage = [self pageViewController:_pageController viewControllerBeforeViewController:newRightPage];
}
if (newLeftPage) {
newDisplayedPages = [[NSArray alloc] initWithObjects:newLeftPage, newRightPage, nil];
}
// If there are two new pages to display, show them with animation.
if (newDisplayedPages) {
[_pageController setViewControllers:newDisplayedPages direction:UIPageViewControllerNavigationDirectionReverse animated:YES completion:nil];
}
}
对于单页面,我只是编辑了@Jack Humphries的答案。
-(void)viewDidLoad
{
counter = 0;
}
-(IBAction)buttonClick:(id)sender
{
counter++;
DataViewController *secondVC = [self.modelController viewControllerAtIndex:counter storyboard:self.storyboard];
NSArray *viewControllers = nil;
viewControllers = [NSArray arrayWithObjects:secondVC, nil];
[self.pageViewController setViewControllers:viewControllers direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:NULL];
}
无论如何,您都需要这个简单的函数:
var currentIndex: Int {
if let visibleViewController = viewControllers?.first,
let ci = pages.firstIndex(of: visibleViewController) {
return ci
}
else {
return 0
}
}
然后对任何给定页面进行动画处理就很容易了:
public func go(toIndex: Int) {
setViewControllers(
[pages[toIndex]],
direction: ((currentIndex < toIndex) ? .forward : .reverse),
animated: true)
}
就是这样。
...
@property (nonatomic, strong) UIViewController *currentViewController;
@property (nonatomic, strong) UIViewController *nextViewController;
...
首先将 currentViewController 初始化为 UIPageViewController 设置的初始视图控制器。
- (void) viewDidLoad {
[super viewDidLoad];
...
self.currentViewController = self.viewControllers[0];
...
[self.pageViewController setViewControllers: @[self.currentViewController] direction: dir animated: YES completion: nil];
}
- (nullable UIViewController *) pageViewController: (UIPageViewController *) pageViewController viewControllerBeforeViewController: (UIViewController *) viewController {
NSInteger idx = [self.viewControllers indexOfObject: viewController];
if (idx > 0) {
return self.viewControllers[idx - 1];
} else {
return nil;
}
}
- (nullable UIViewController *) pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController: (UIViewController *) viewController {
NSInteger idx = [self.viewControllers indexOfObject: viewController];
if (idx == NSNotFound) {
return nil;
} else {
if (idx + 1 < self.viewControllers.count) {
return self.viewControllers[idx + 1];
} else {
return nil;
}
}
}
- (void) pageViewController:(UIPageViewController *)pageViewController willTransitionToViewControllers:(NSArray<UIViewController *> *)pendingViewControllers {
self.nextViewController = [pendingViewControllers firstObject];
}
- (void)pageViewController:(UIPageViewController *)pageViewController didFinishAnimating:(BOOL)finished previousViewControllers:(NSArray<UIViewController *> *)previousViewControllers transitionCompleted:(BOOL)completed {
if (completed) {
self.currentViewController = self.nextViewController;
}
}
- (void) onNext {
UIViewController *vc = [self pageViewController: self.tutorialViewController viewControllerAfterViewController: self.currentViewController];
if (vc != nil) {
self.currentViewController = vc;
[self.tutorialViewController setViewControllers: @[vc] direction: UIPageViewControllerNavigationDirectionForward animated: YES completion: nil];
}
}
我从昨天开始就在处理这个问题,最终我让它工作了。我不能完全使用标准模板,因为我有三个不同的视图控制器作为子视图:
1 - rootViewController;
2 - model;
3 - viewControllers
3.1 - VC1;
3.2 - VC2;
3.3 - VC3.
Note: all of VCs has Storyboard ID.
我只需要在第一个VC中添加一个触发按钮,因此我为pageViewController和model添加了一个属性:
#import <UIKit/UIKit.h>
#import "Model.h"
@interface VC1 : UIViewController
@property (nonatomic, strong) UIPageViewController *thePageViewController;
@property (nonatomic, strong) SeuTimePagesModel *theModel;
@end
- (id)initWithStoryboard:(UIStoryboard *)storyboard
andPageViewController:(UIPageViewController *)controller
{
if (self = [super init])
{
VC1 *vc1 = [storyboard instantiateViewControllerWithIdentifier:@"VC1"];
vc1.pageViewController = controller;
vc1.model = self;
VC2 *vc2 = [storyboard instantiateViewControllerWithIdentifier:@"VC2"];
VC3 *vc3 = [storyboard instantiateViewControllerWithIdentifier:@"VC3"];
self.pageData = [[NSArray alloc] initWithObjects:vc1, vc2, vc3, nil];
}
return self;
}
- (IBAction)go:(id)sender
{
VC2 *vc2 = [_model.pages objectAtIndex:1];
NSArray *viewControllers = @[vc2];
[_pageViewController setViewControllers:viewControllers
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:nil];
}
注意:我不需要查找VC的索引,我的按钮会带我到第二个VC,但获取所有索引并跟踪子视图并不难:
- (IBAction)selecionaSeuTime:(id)sender
{
NSUInteger index = [_model.pages indexOfObject:self];
index++;
VC2 *vc2 = [_model.pages objectAtIndex:1];
NSArray *viewControllers = @[vc2];
[_pageViewController setViewControllers:viewControllers
direction:UIPageViewControllerNavigationDirectionForward
animated:YES
completion:nil];
}
希望这对你有所帮助!
正如@samwize所指出的那样,分页的方法是使用
setViewControllers:array
由于ViewControllers嵌入在PageViewController中,您只需要执行以下操作:
以下是Xamarin的示例,但与Swift等功能类似。以下代码将在作为页面显示的其中一个ViewControllers中的Button Click委托中:
var parent = ParentViewController as WelcomePageViewController;
var next = parent.DataSource.GetNextViewController(parent, this);
parent.SetViewControllers(new UIViewController[] { next }, UIPageViewControllerNavigationDirection.Forward, true, null);