UIPageViewController 缓存

Posted 2023-03-11

【中文标题】UIPageViewController 缓存

【英文标题】：UIPageViewController caching

【发布时间】：2014-06-04 10:01:14

【问题描述】：

我有一个带有动态变化数据源的 UIPageViewController -

viewControllerAfterViewController

和

viewControllerBeforeViewController

如果数据还没有准备好，则返回 nil，如果数据准备好，则返回视图控制器。如果我尝试在某些时候快速向左翻页多次 viewControllerAfterViewController 将不再被调用。

可能是什么问题？我想 UIPageViewController 认为它知道一切并且什么都没有改变，所以它不调用那个方法，对吗？如何“重置”此缓存？

我使用 curl 过渡样式，这似乎只发生在横向模式下。

【参考方案1】：

我最终使用了自己的滑动手势。

首先从 UIPageViewController 中移除现有的滑动手势

for (UIGestureRecognizer * recognizer in _pageViewController.gestureRecognizers) 
    recognizer.enabled = NO;

然后将你自己的滑动手势识别器添加到 UIPageViewController

UISwipeGestureRecognizer * rightRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleRightSwipe:)];
[rightRecognizer setDirection:(UISwipeGestureRecognizerDirectionLeft)];
[_pageViewController.view addGestureRecognizer:rightRecognizer];

UISwipeGestureRecognizer * leftRecognizer = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleLeftSwipe:)];
[leftRecognizer setDirection:(UISwipeGestureRecognizerDirectionRight)];
[_pageViewController.view addGestureRecognizer:leftRecognizer];

- (void) handleRightSwipe: (id) sender 
// your swipe handler here 
// note that you need  to call didFinishAnimating manually now

// manually calculate next/prev view controller, also you should consider orientation too
 UIViewController * nextController = [_modelController pageViewController:_pageViewController viewControllerAfterViewController:existingController];


__weak typeof(self) weakSelf = self;
__weak UIPageViewController * wController = _pageViewController;
[_pageViewController setViewControllers:@[nextController] direction:
    UIPageViewControllerNavigationDirectionForward animated:YES completion:^(BOOL completed)
        [weakSelf pageViewController:wController didFinishAnimating:YES previousViewControllers:@[existingController] transitionCompleted:YES];
    ];
  
 

此外，您可以尝试不删除现有的滑动手势，如果现有识别器触发，它看起来不会调用您的自定义滑动手势，这样您在拖动页面角时也有很好的动画（如果您删除所有识别器）。