获取RecyclerView可见项 [英] Get visible items in RecyclerView

问题描述

我需要知道哪些元素在我的RecyclerView当前显示。没有等同于<一个href="http://developer.android.com/reference/android/widget/AbsListView.OnScrollListener.html#onScroll%28android.widget.AbsListView,%20int,%20int,%20int%29"><$c$c>OnScrollListener.onScroll(...)方法上的列表视图。我试图与合作<一个href="http://developer.android.com/reference/android/view/View.html#getGlobalVisibleRect%28android.graphics.Rect,%20android.graphics.Point%29"><$c$c>View.getGlobalVisibleRect(...),但黑客是太丑陋，不总是工作了。

I need to know which elements are currently displayed in my RecyclerView. There is no equivalent to the OnScrollListener.onScroll(...) method on ListViews. I tried to work with View.getGlobalVisibleRect(...), but that hack is too ugly and does not always work too.

有人什么想法？

推荐答案

第一个/最后一个可见子依赖于布局管理。 如果您使用的是LinearLayoutManager或GridLayoutManager，你可以使用

first / last visible child depends on the LayoutManager. If you are using LinearLayoutManager or GridLayoutManager, you can use

int findFirstVisibleItemPosition();
int findFirstCompletelyVisibleItemPosition();
int findLastVisibleItemPosition();
int findLastCompletelyVisibleItemPosition();

例如：

GridLayoutManager layoutManager = ((GridLayoutManager)mRecyclerView.getLayoutManager());
int firstVisiblePosition = layoutManager.findFirstVisibleItemPosition();

有关LinearLayoutManager，第一/最后取决于适配器排序。不询问从RecyclerView儿童;布局管理可能preFER布局比可见多个项目进行缓存。

For LinearLayoutManager, first/last depends on the adapter ordering. Don't query children from RecyclerView; LayoutManager may prefer to layout more items than visible for caching.

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