跟踪列表的所有项目当前在屏幕上可见 [英] Tracking what all items of a list are currently visible on the screen

问题描述

假设我有一个包含10个项目的recyclerview.在这10个中，一次就能看到0-4.向下滚动时，第0个元素离开屏幕，第5个元素进入.我想跟踪这些事件-我知道元素0-4是可见的，然后滚动时是1-5.

Suppose I have a recyclerview with 10 items. Out of these 10, 0 - 4 are visible in one go. On scrolling down, 0th element goes away from the screen and 5th one enters. I want to track these events - where I get to know that elements 0 - 4 are visible and then on scrolling, 1-5 are.

反正有实现这一目标的方法吗?我想跟踪用户花了多长时间在recyclerview的特定项目上.

Is there anyway to achieve this? I want to keep track of how long a user is spending time on a particular items of the recyclerview.

推荐答案

在RecyclerView上设置 addOnScrollListener 并获取第一个和最后一个可见行

set addOnScrollListener on RecyclerView and get first and last visible rows

recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
        if (newState == RecyclerView.SCROLL_STATE_IDLE) {
            int firstVisiblePosition = ((LinearLayoutManager)recyclerView.getLayoutManager()).findFirstCompletelyVisibleItemPosition();
            int lastVisiblePosition = ((LinearLayoutManager)recyclerView.getLayoutManager()).findLastCompletelyVisibleItemPosition();

            // Now you can easily get all rows b/w first and last item
        }
    }
});

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