iOS：UIPageViewController - 使用按钮跳转到下一页

Question

我有一系列VCs在PageViewController中，用户可以通过手指从左到右导航。我需要添加按钮，这些按钮基本上执行与手指滑动相同的操作，通过VCs向左或向右移动一个。我该怎么做？现在，我正在使用这两种方法来动态设置VCs，因为用户滑动：

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

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

如果用户点击按钮，我是否有办法做同样的事情？

- user2563044

Answer 1

使用setViewControllers:direction:animated:completion:方法可以编程设置当前显示的视图控制器，并使用过渡动画。这是一个示例，它呈现具有随机背景颜色的视图控制器。您可以将其调整为使用您特定的视图控制器。

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.pvc = [[UIPageViewController alloc] initWithTransitionStyle:UIPageViewControllerTransitionStyleScroll navigationOrientation:UIPageViewControllerNavigationOrientationHorizontal options:nil];
    self.pvc.view.frame = CGRectInset(self.view.bounds, 200, 200);
    [self.view addSubview:self.pvc.view];

    [self.pvc setViewControllers:@[[self randomVC]] direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];
}

-(UIViewController*)randomVC
{
    UIViewController *vc = [[UIViewController alloc] init];
    UIColor *color = [UIColor colorWithRed:arc4random_uniform(255)/255.0 green:arc4random_uniform(255)/255.0 blue:arc4random_uniform(255)/255.0 alpha:1];
    vc.view.backgroundColor = color;
    return vc;
}

- (IBAction)previousButtonPressed:(id)sender {
    [self.pvc setViewControllers:@[[self randomVC]] direction:UIPageViewControllerNavigationDirectionReverse animated:YES completion:nil];
}

- (IBAction)nextButtonPressed:(id)sender {
    [self.pvc setViewControllers:@[[self randomVC]] direction:UIPageViewControllerNavigationDirectionForward animated:YES completion:nil];
}

- MJN

---

可以了！我还需要理解UIPageViewController背后的思想，但在此期间感谢您提供的解决方案 :) - user2563044

不客气。这实际上只是将内容带到屏幕上的另一种方式。而且，这个内容是在UIViewController子类中的。你可以使用这种技术使你的代码更加模块化，并使逻辑驻留在适当的视图控制器中，而不是在你的主视图控制器中。 - MJN

@MJN 如果前进和后退按钮分别放置在各自的视图控制器（页面）中，我们如何从那里调用IBAction方法？请回复。 - user3404693

你有几个选项。你可以让这些按钮调用自定义委托方法。你可以让这些按钮调用你指定的块。你也可以使用 UIControl 调用响应者链。 - MJN

这将从UIPageViewController中删除您以前的ViewController，因此如果您返回，您将获得一个新的ViewController。我的UIPageViewController控制注册过程，因此我需要保存先前VC的文本字段文本。有人能解释一下如何做到这一点吗？ - datWooWoo

Answer 2

如果页面可以通过添加的按钮（上一页，下一页）和滑动（开启页面控制）进行导航，请查看以下内容：

//Set Delegate & Data Source for PageView controller [Say in View Did Load]
   self.pageViewController.dataSource = self;
   self.pageViewController.delegate = self;



// PageBefore & After When User Scroll to move next or previous page 

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

    [_nextBtn setTitle:@"Next" forState:UIControlStateNormal];

    NSUInteger index = ((PageContentViewController*) viewController).pageIndex;

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

    if (index > 0)
    {
        index--;
    }
    else
    {
        return nil;
    }

    return [self viewControllerAtIndex:index];

}

- (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerAfterViewController:(UIViewController *)viewController{
    NSUInteger index = ((PageContentViewController*) viewController).pageIndex;

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


if (index < 3)
{
    index++;
}else
{
    return nil;
}
return [self viewControllerAtIndex:index];}

//To Match Exact Index page view when scrolled & navigated using button action. Place button index when page is been translated.



 - (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;
}
}

//上一个，下一个按钮的操作

-(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)nextBtnAction:(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
-(NSInteger)presentationCountForPageViewController:(UIPageViewController *)pageViewController{
    return [self.pageImages count];}

-(NSInteger)presentationIndexForPageViewController:(UIPageViewController *)pageViewController{
    return  buttonIndex;}

- Yogesh Lolusare