UIPageviewcontroller:从中间开始

Question

不幸的是，搜索没有帮助我...我有以下问题：我有三个UItableviews（ViewController1，ViewController2和Viewcontroller3），我将它们嵌入到故事板的简单PageViewController屏幕截图中（我还不能在这里插入任何图片：/）。

为了显示三个 ViewController，我将它们放入我的 PageViewController.m（PageViewController 的自定义类）的 viewdidload 中的一个数组中，所以我没有使用 ViewController 作为容器将其他 ViewController 放入：

-(void)viewDidLoad
{
    [super viewDidLoad];
    
    self.delegate = self;
    self.dataSource = self;
    
    UIViewController *p1 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"TableView1"];
    UIViewController *p2 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"TableView2"];
    UIViewController *p3 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"TableView3"];
    
    myViewControllers = @[p1,p2,p3];
    

我可以选择从哪个视图控制器开始，然后选择

- 前进（方向： UIPageViewControllerNavigation**DirectionForward** ）：

        [self setViewControllers:@[p1]
                       direction:UIPageViewControllerNavigationDirectionForward
                        animated:NO completion:nil];
        
        NSLog(@"loaded!");
    }

或选择最后一个并倒退（UIPageViewControllerNavigation**DirectionReverse**）：

        [self setViewControllers:@[p3]
                   direction:UIPageViewControllerNavigationDirectionReverse
                   animated:NO completion:nil];
      

但是，我一直在试图弄清楚如何从ViewController2开始，并在左侧Viewcontroller1，在右侧ViewController3（cp。 截图）

任何建议或代码片段将不胜感激！

这是整个代码：

#import "StartScreenPageViewController.h"
@interface StartScreenPageViewController ()
@end
@implementation StartScreenPageViewController
{
    NSArray *myViewControllers;
}
-(void)viewDidLoad
{
    [super viewDidLoad];
    
    self.delegate = self;
    self.dataSource = self;
    
    UIViewController *p1 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"1"];
    UIViewController *p2 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"2"];
    UIViewController *p3 = [self.storyboard
                            instantiateViewControllerWithIdentifier:@"3"];
    
    myViewControllers = @[p1,p2,p3];
    
    [self setViewControllers:@[p1]
                   direction:UIPageViewControllerNavigationDirectionForward
                    animated:NO completion:nil];
    
    NSLog(@"loaded!");
}
-(UIViewController *)viewControllerAtIndex:(NSUInteger)index
{
    return myViewControllers[index];
}
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController
     viewControllerBeforeViewController:(UIViewController *)viewController
{
    NSUInteger currentIndex = [myViewControllers indexOfObject:viewController];
    
    --currentIndex;
    currentIndex = currentIndex % (myViewControllers.count);
    return [myViewControllers objectAtIndex:currentIndex];
}
-(UIViewController *)pageViewController:(UIPageViewController *)pageViewController
      viewControllerAfterViewController:(UIViewController *)viewController
{
    NSUInteger currentIndex = [myViewControllers indexOfObject:viewController];
    
    ++currentIndex;
    currentIndex = currentIndex % (myViewControllers.count);
    return [myViewControllers objectAtIndex:currentIndex];
}
-(NSInteger)presentationCountForPageViewController:
(UIPageViewController *)pageViewController
{
    return myViewControllers.count;
}
-(NSInteger)presentationIndexForPageViewController:
(UIPageViewController *)pageViewController
{
    return 0;
}
@end

Answer 1

您应该能够在 viewDidLoad 中设置初始视图控制器。您已经在这样做了，但您正在将其设置为第一个视图控制器：

 [self setViewControllers:@[p1]
                   direction:UIPageViewControllerNavigationDirectionForward
                    animated:NO completion:nil];

我认为您应该能够将其更改为：

 [self setViewControllers:@[p2]
                   direction:UIPageViewControllerNavigationDirectionForward
                    animated:NO completion:nil];

然后，只需确保pageViewController:viewControllerAfterViewController和pageViewController:viewControllerBeforeViewController方法根据所需的功能处理数据源的上下迭代。