ViewPager 作为循环队列/包装 [英] ViewPager as a circular queue / wrapping

问题描述

我正在使用带有 FragmentStatePagerAdapter 的 ViewPager 以允许在某些片段之间导航.

I am using a ViewPager with the FragmentStatePagerAdapter to allow navigation between some fragments.

假设我有三个片段:A、B 和 C.ViewPager 最初显示 Fragment A，并允许您通过从右向左滑动导航到 Fragment B，然后再次滑动导航到 Fragment C.这允许以下导航路径: A <-->B<-->C.

Let's say I have three fragments: A, B and C. The ViewPager shows Fragment A initially, and allows you to navigate to Fragment B by swiping from right-to-left, and then to Fragment C by swiping again. This allows the following navigation paths: A <--> B <--> C.

我想要的是能够在片段 A 上从左到右滑动并让 ViewPager 显示片段 C，即让它表现为循环队列并允许 ... -->C<--><-->B<-->C<-->一个 <-- ...

What I would like is to be able to swipe from left-to-right on Fragment A and have the ViewPager show Fragment C, i.e. for it to behave as a circular queue and allow ... --> C <--> A <--> B <--> C <--> A <-- ...

我不希望 Fragments 在其他位置重复(即以三个以上的实例结束).

I do not want the Fragments duplicated in other positions (i.e. ending up with more than three instances).

ViewPager 是否可以实现这种包装功能?

Is this wrapping functionality possible with a ViewPager?

推荐答案

我已经实现了一个 ViewPager/PagerAdapter，它可以允许伪无限分页行为.它的工作原理是指定一个非常大的数字作为实际计数，但将它们映射到数据集/页面集的实际范围.它还会将开头偏移一个大数字，以便您可以立即从第一"页向左滚动.

I've implemented a ViewPager/PagerAdapter that can allow for pseudo-infinite paging behaviour. It works by specifying a very large number as the actual count, but maps them to the actual range of the dataset/pageset. It offsets the beginning by a large number also so that you can immediately scroll to the left from the 'first' page.

一旦您到达第 1,000,000 页(滚动时您会看到图形故障)，它就不会那么好用，但这通常不是现实世界的用例.我可以通过偶尔将计数重置为较低的数字来解决此问题，但我暂时保持原样.

It doesn't work so well once you get to 1,000,000th page (you will see graphical glitches when scrolling), but this is typically not a real-world use-case. I could fix this by resetting the count to a lower number once in a while, but I will leave it how it is for now.

InfinitePagerAdapter 包装了一个现有的 ViewPager，所以使用是非常透明的.InfiniteViewPager 做了一些工作，以确保您可以多次向左和向右滚动.

The InfinitePagerAdapter wraps an existing ViewPager, and so the usage is quite transparent. The InfiniteViewPager does does a bit of work to make sure you can potentially scroll to the left and right many times.

https://github.com/antonyt/InfiniteViewPager

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