如何在UICollectionView中使用useLayoutToLayoutNavigationTransitions？ [英] How to use useLayoutToLayoutNavigationTransitions in UICollectionView?

问题描述

我试图在iOS7集合视图中学习新的布局过渡效果。

I was trying to learn the new layout transition effect in iOS7 collection view.

然而，我根本无法让它工作。我在下面附上了一个屏幕截图说明。

However, I am unable to get it to work at all. I have attached a screen shot description below.

我知道当此Transition效果生效时，控制器之间使用相同的Collection View。但是，为什么在转换发生时该集合视图不会重新加载。我甚至尝试重新加载集合视图太失败了。

I am aware that the same Collection View is used between Controllers when this Transition effect is in effect. But, why that collection view is not reloading when transition is happening. I even tried Reloading the collection view an that too failed.

应该有一些简单的观点我应该遗漏。请帮帮我。

There should be some simple point I should be missing. Help me please.

我附上了以下源代码。

    UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
    flowLayout.itemSize = CGSizeMake(75.0, 70.0);

    ALCollectionViewNoXibController* controller = [[ALCollectionViewNoXibController alloc] initWithCollectionViewLayout:flowLayout];
    controller.numberOfItems = _numberOfItems-1;
controller.transitionType = _transitionType;
    if (_transitionType == kLayoutTransition) {
        controller.useLayoutToLayoutNavigationTransitions = YES;
    }
   [self.navigationController pushViewController:controller animated:YES];

项目代码

推荐答案

新的您正在加载的flowLayout 确实正在使用。你可以看到它，例如，你做 flowLayout.itemSize = CGSizeMake（10.0 * _numberOfItems，10.0 * _numberOfItems）;

The new flowLayout that you are loading is indeed being used. You can see it if for instance, you do flowLayout.itemSize = CGSizeMake(10.0*_numberOfItems, 10.0*_numberOfItems);

您的问题是，为了使转换工作，iOS将在动画过渡期间更改您的数据源。

Your issue is that in order to make the transition work, iOS will change your datasource during the animated transition.

试试这个：

让你的班级成为导航代表：

Make your class a Navigation delegate:

@interface ALCollectionViewNoXibController ()<UINavigationControllerDelegate>

然后在推送之前将导航的代理设置为当前控制器

Then set the delegate of the navigation to the current controller, before pushing

self.navigationController.delegate = self;
[self.navigationController pushViewController:controller animated:YES];

现在你可以添加

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {

   ALCollectionViewNoXibController *controller = (ALCollectionViewNoXibController *)viewController;
   navigationController.delegate = controller;
   controller.collectionView.dataSource = controller;
}

当你导航回顶层控制器时，这个简单的例子将会中断，因为收到的viewController不是 ALCollectionViewNoXibController 类。但是你明白了。

This simple example will break when you navigate back to the top controller, because the viewController received is not of ALCollectionViewNoXibController class. But you get the idea.

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