序文

在笔直滑动的过程中能够横向翻滚内容。

作用

代码

就一个工具类就行了。能够通过root view向上查找recycleView。自动增加翻滚监听。在子view完全显示出来以后，才分发翻滚事情。这样用户才能看清楚第一个。

需要一个id资源

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <item name="key_rv_scroll_helper" type="id"/>
</resources>

RVScrollHelper

package com.trs.myrb.provider.scroll;
import android.view.View;
import android.view.ViewParent;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.trs.myrb.R;
import com.trs.myrb.douyin.action.TRSFunction;
/**
 * <pre>
 * Created by zhuguohui
 * Date: 2023/5/12
 * Time: 13:49
 * Desc:用于监听recycleView的笔直翻滚，然后将笔直翻滚转发给其他类。
 *
 *  //在provider中运用
 *     RVScrollHelper.create(binding.getRoot(), dy -> {
 *             binding.rvHotVideos.scrollBy(dy,0);
 *             return null;
 *         });
 * </pre>
 */
public class RVScrollHelper implements View.OnAttachStateChangeListener {
    TRSFunction<Integer, Void> scrollCallBack;
    View child;
    RecyclerView recyclerView;
    private int recyclerViewHeight;
    public static RVScrollHelper create(View child,TRSFunction<Integer, Void> scrollCallBack){
        if(child==null){
            return null;
        }
        Object tag = child.getTag(R.id.key_rv_scroll_helper);
        if(!(tag instanceof RVScrollHelper)){
            RVScrollHelper helper = new RVScrollHelper(child, scrollCallBack);
            tag=helper;
            child.setTag(R.id.key_rv_scroll_helper,helper);
        }
        return (RVScrollHelper) tag;
    }
    private RVScrollHelper(View child, TRSFunction<Integer, Void> scrollCallBack) {
        this.scrollCallBack = scrollCallBack;
        this.child = child;
        this.child.addOnAttachStateChangeListener(this);
    }
    @Override
    public void onViewAttachedToWindow(View v) {
        if(child==null){
            return;
        }
        if (recyclerView == null) {
            recyclerView = getRecyclerView(v);
            recyclerViewHeight = recyclerView.getHeight();
            recyclerView.addOnScrollListener(onScrollListener);
        }
    }
    @Override
    public void onViewDetachedFromWindow(View v) {
        if(recyclerView!=null) {
            recyclerView.removeOnScrollListener(onScrollListener);
            recyclerView=null;
        }
    }
    private RecyclerView.OnScrollListener onScrollListener=new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
        }
        @Override
        public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
            //只有在view全部显示出来以后，才发送翻滚事情
            boolean isAllShow=isAllShow();
            if(isAllShow){
                if(scrollCallBack!=null){
                    scrollCallBack.call(dy);
                }
            }
        }
    };
    private boolean isAllShow() {
        int top = child.getTop();
        int bottom = child.getBottom();
        return bottom>=0&&bottom<=recyclerViewHeight;
    }
    private RecyclerView getRecyclerView(View v) {
        ViewParent parent = v.getParent();
        while (!(parent instanceof RecyclerView) && parent != null) {
            parent = parent.getParent();
        }
        if(parent!=null){
            return (RecyclerView) parent;
        }
        return null;
    }
}

运用

在provider中运用。

  RVScrollHelper.create(holder.itemView, dy -> {
            recyclerView.scrollBy(dy, 0);
            return null;
        });