Android RecyclerView曝光采集

一、背景

近期pm提出需要统计首页商品的曝光亮，由于我们的首页是用的recylerview实现的，这里就来讲下如何使用监听recylerview的滚动事件来实现子view的曝光量统计，我们这里说的view都是列表中的子item条目（子view）

二、监听recylerview的滚动事件OnScrollListener

onScrollStateChanged：监听滚动状态
onScrolled：监听滚动
我们接下来的统计工作，就是拿这两个方法做文章。

//检测recylerview的滚动事件
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {@Overridepublic void onScrollStateChanged(RecyclerView recyclerView, int newState) {/*我这里通过的是停止滚动后屏幕上可见view。如果滚动过程中的可见view也要统计，你可以根据newState去做区分SCROLL_STATE_IDLE:停止滚动SCROLL_STATE_DRAGGING: 用户慢慢拖动SCROLL_STATE_SETTLING：惯性滚动*/if (newState == RecyclerView.SCROLL_STATE_IDLE) {.....}}@Overridepublic void onScrolled(RecyclerView recyclerView, int dx, int dy) {super.onScrolled(recyclerView, dx, dy);........}});

首先再次明确下，我们要统计的是用户停止滑动时，显示在屏幕的上控件。所以我们要监测到onScrollStateChanged 方法中
newState == RecyclerView.SCROLL_STATE_IDLE 时，也就是用户停止滚动。然后在这里做文章

三、获取屏幕内可见条目的起始位置

这里的起始位置就是指我们屏幕当中最上面和最下面条目的位置。比如下图的0就是最上面的可见条目，3就是最下面的可见条目。我们次数的曝光view就是0，1，2，3 这个时候这四个条目显示在屏幕中。我们这时就要对这4个view的曝光量进行加1
那么接下来的重点就是要去获取屏幕内可见条目的起始位置。获取到起始位置后，当前屏幕里的可见条目就都能拿到了。
而recylerview的manager正好给我们提供的有对应的方法。
findFirstVisibleItemPosition()和findLastVisibleItemPosition() 看字面意思就能知道这时干嘛用的。
但是我们的manager不止LinearLayoutManager一种，所以我们要做下区分

//这里我们用一个数组来记录起始位置
int[] range = new int[2];
RecyclerView.LayoutManager manager = reView.getLayoutManager();
if (manager instanceof LinearLayoutManager) {range = findRangeLinear((LinearLayoutManager) manager);
} else if (manager instanceof GridLayoutManager) {range = findRangeGrid((GridLayoutManager) manager);
} else if (manager instanceof StaggeredGridLayoutManager) {range = findRangeStaggeredGrid((StaggeredGridLayoutManager) manager);
}

LinearLayoutManager和GridLayoutManager获取起始位置方法如下

private int[] findRangeLinear(LinearLayoutManager manager) {int[] range = new int[2];range[0] = manager.findFirstVisibleItemPosition();range[1] = manager.findLastVisibleItemPosition();return range;
}
private int[] findRangeGrid(GridLayoutManager manager) {int[] range = new int[2];range[0] = manager.findFirstVisibleItemPosition();range[1] = manager.findLastVisibleItemPosition();return range;
}

StaggeredGridLayoutManager获取起始位置有点复杂，如下

private int[] findRangeStaggeredGrid(StaggeredGridLayoutManager manager) {int[] startPos = new int[manager.getSpanCount()];int[] endPos = new int[manager.getSpanCount()];manager.findFirstVisibleItemPositions(startPos);manager.findLastVisibleItemPositions(endPos);int[] range = findRange(startPos, endPos);return range;
}private int[] findRange(int[] startPos, int[] endPos) {int start = startPos[0];int end = endPos[0];for (int i = 1; i < startPos.length; i++) {if (start > startPos[i]) {start = startPos[i];}}for (int i = 1; i < endPos.length; i++) {if (end < endPos[i]) {end = endPos[i];}}int[] res = new int[]{start, end};return res;
}

四、获取到起始位置以后，我们就根据位置获取到view及view中的数据

上面第三步拿到屏幕内可见条目的起始位置以后，我们就用一个for循环，获取当前屏幕内可见的所有子view

for (int i = range[0]; i <= range[1]; i++) {View view = manager.findViewByPosition(i);recordViewCount(view);
}

recordViewCount是我自己写的用于获取子view内绑定数据的方法

//获取view绑定的数据
private void recordViewCount(View view) {if (view == null || view.getVisibility() != View.VISIBLE ||!view.isShown() || !view.getGlobalVisibleRect(new Rect())) {return;}int top = view.getTop();int halfHeight = view.getHeight() / 2;int screenHeight = UiUtils.getScreenHeight((Activity) view.getContext());int statusBarHeight = UiUtils.getStatusBarHeight(view.getContext());if (top < 0 && Math.abs(top) > halfHeight) {return;}if (top > screenHeight - halfHeight - statusBarHeight) {return;}//这里获取的是我们view绑定的数据，相应的你要去在你的view里setTag，只有set了，才能getItemData tag = (ItemData) view.getTag();String key = tag.toString();if (TextUtils.isEmpty(key)) {return;}hashMap.put(key, !hashMap.containsKey(key) ? 1 : (hashMap.get(key) + 1));Log.i("qcl0402", key + "----出现次数：" + hashMap.get(key));
}

这里有几点需要注意

这这里起始位置的view显示区域如果不超过50%，就不算这个view可见，进而也就不统计曝光。
我们通过view.getTag();获取view里的数据，必须在此之前setTag()数据，我这里setTag是在viewholder中把数据set进去的

到这里我们就实现了recylerview列表中view控件曝光量的统计了。下面贴出来完整的代码给大家

package com.example.qcl.demo.xuexi.baoguang;import android.app.Activity;
import android.graphics.Rect;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;import com.example.qcl.demo.utils.UiUtils;import java.util.concurrent.ConcurrentHashMap;/*** 2019/4/2 13:31* author: qcl* desc: 安卓曝光量统计工具类* wechat:2501902696*/
public class ViewShowCountUtils {//刚进入列表时统计当前屏幕可见viewsprivate boolean isFirstVisible = true;//用于统计曝光量的mapprivate ConcurrentHashMap<String, Integer> hashMap = new ConcurrentHashMap<String, Integer>();/** 统计RecyclerView里当前屏幕可见子view的曝光量** */void recordViewShowCount(RecyclerView recyclerView) {hashMap.clear();if (recyclerView == null || recyclerView.getVisibility() != View.VISIBLE) {return;}//检测recylerview的滚动事件recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {@Overridepublic void onScrollStateChanged(RecyclerView recyclerView, int newState) {/*我这里通过的是停止滚动后屏幕上可见view。如果滚动过程中的可见view也要统计，你可以根据newState去做区分SCROLL_STATE_IDLE:停止滚动SCROLL_STATE_DRAGGING: 用户慢慢拖动SCROLL_STATE_SETTLING：惯性滚动*/if (newState == RecyclerView.SCROLL_STATE_IDLE) {getVisibleViews(recyclerView);}}@Overridepublic void onScrolled(RecyclerView recyclerView, int dx, int dy) {super.onScrolled(recyclerView, dx, dy);//刚进入列表时统计当前屏幕可见viewsif (isFirstVisible) {getVisibleViews(recyclerView);isFirstVisible = false;}}});}/** 获取当前屏幕上可见的view* */private void getVisibleViews(RecyclerView reView) {if (reView == null || reView.getVisibility() != View.VISIBLE ||!reView.isShown() || !reView.getGlobalVisibleRect(new Rect())) {return;}//保险起见，为了不让统计影响正常业务，这里做下try-catchtry {int[] range = new int[2];RecyclerView.LayoutManager manager = reView.getLayoutManager();if (manager instanceof LinearLayoutManager) {range = findRangeLinear((LinearLayoutManager) manager);} else if (manager instanceof GridLayoutManager) {range = findRangeGrid((GridLayoutManager) manager);} else if (manager instanceof StaggeredGridLayoutManager) {range = findRangeStaggeredGrid((StaggeredGridLayoutManager) manager);}if (range == null || range.length < 2) {return;}Log.i("qcl0402", "屏幕内可见条目的起始位置：" + range[0] + "---" + range[1]);for (int i = range[0]; i <= range[1]; i++) {View view = manager.findViewByPosition(i);recordViewCount(view);}} catch (Exception e) {e.printStackTrace();}}//获取view绑定的数据private void recordViewCount(View view) {if (view == null || view.getVisibility() != View.VISIBLE ||!view.isShown() || !view.getGlobalVisibleRect(new Rect())) {return;}int top = view.getTop();int halfHeight = view.getHeight() / 2;int screenHeight = UiUtils.getScreenHeight((Activity) view.getContext());int statusBarHeight = UiUtils.getStatusBarHeight(view.getContext());if (top < 0 && Math.abs(top) > halfHeight) {return;}if (top > screenHeight - halfHeight - statusBarHeight) {return;}//这里获取的是我们view绑定的数据，相应的你要去在你的view里setTag，只有set了，才能getItemData tag = (ItemData) view.getTag();String key = tag.toString();if (TextUtils.isEmpty(key)) {return;}hashMap.put(key, !hashMap.containsKey(key) ? 1 : (hashMap.get(key) + 1));Log.i("qcl0402", key + "----出现次数：" + hashMap.get(key));}private int[] findRangeLinear(LinearLayoutManager manager) {int[] range = new int[2];range[0] = manager.findFirstVisibleItemPosition();range[1] = manager.findLastVisibleItemPosition();return range;}private int[] findRangeGrid(GridLayoutManager manager) {int[] range = new int[2];range[0] = manager.findFirstVisibleItemPosition();range[1] = manager.findLastVisibleItemPosition();return range;}private int[] findRangeStaggeredGrid(StaggeredGridLayoutManager manager) {int[] startPos = new int[manager.getSpanCount()];int[] endPos = new int[manager.getSpanCount()];manager.findFirstVisibleItemPositions(startPos);manager.findLastVisibleItemPositions(endPos);int[] range = findRange(startPos, endPos);return range;}private int[] findRange(int[] startPos, int[] endPos) {int start = startPos[0];int end = endPos[0];for (int i = 1; i < startPos.length; i++) {if (start > startPos[i]) {start = startPos[i];}}for (int i = 1; i < endPos.length; i++) {if (end < endPos[i]) {end = endPos[i];}}int[] res = new int[]{start, end};return res;}
}