Android两条并排RecyclerView实时联动滑动增强

Android两条并排RecyclerView实时联动滑动增强

在附录1中，我初步实现了两条垂直摆放的RecyclerView的实时联动滚动，但是附录文章1的实现存在一定问题，比如当用户的手指同时在屏幕的两条RecyclerView区域内滑动，将发生异常。还有就是，比如在RecyclerView1正在滚动时候，用户又在RecyclerView2的区域内手指滑动，这样将触发循环嵌套滚动事件，引发错误，因此本文在附录1的基础上改进，通过拦截处理系统的触摸事件解决造成RecyclerView滚动引发的问题。
代码：

package zhangphil.test;

import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;

public class RVActivity extends AppCompatActivity {
    private RecyclerView mRecyclerView1;
    private RecyclerView mRecyclerView2;

    private ArrayList<Integer> mItems;

    /**
     * 返回true，表示拦截事件。
     * 返回false，表示不做任何处理，交给子View处理。
     *
     * @param event
     * @return
     */
    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        /**
         * 如果用户的手指同时放在屏幕上滑动，不要触发滚动事件。
         *
         */
        if (event.getPointerCount() >= 2) {
            return true;
        }

        /**
         * 如果左侧的RecyclerView1在滚动中，但是此时用户又在RecyclerView2中触发滚动事件，则停止所有滚动，等待新一轮滚动。
         *
         */
        if (mRecyclerView1.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) {
            if (touchEventInView(mRecyclerView2, event.getX(), event.getY())) {
                mRecyclerView1.stopScroll();
                mRecyclerView2.stopScroll();
                return true;
            }
        }

        /**
         * 如果右侧的RecyclerView2在滚动中，但是此时用户又在RecyclerView1中触发滚动事件，则停止所有滚动，等待新一轮滚动。
         *
         */
        if (mRecyclerView2.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) {
            if (touchEventInView(mRecyclerView1, event.getX(), event.getY())) {
                mRecyclerView2.stopScroll();
                mRecyclerView1.stopScroll();
                return true;
            }
        }

        return super.dispatchTouchEvent(event);
    }

    private boolean touchEventInView(View view, float x, float y) {
        if (view == null) {
            return false;
        }

        int[] location = new int[2];
        view.getLocationOnScreen(location);

        int left = location[0];
        int top = location[1];

        int right = left + view.getMeasuredWidth();
        int bottom = top + view.getMeasuredHeight();

        if (y >= top && y <= bottom && x >= left && x <= right) {
            return true;
        }

        return false;
    }

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rv_activity);

        mItems = new ArrayList<>();
        for (int i = 0; i < 10000; i++) {
            mItems.add(i);
        }

        initRecyclerView1();
        initRecyclerView2();

        mRecyclerView1.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                if (recyclerView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) {
                    mRecyclerView2.scrollBy(dx, dy);
                }
            }
        });

        mRecyclerView2.addOnScrollListener(new RecyclerView.OnScrollListener() {
            @Override
            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                if (recyclerView.getScrollState() != RecyclerView.SCROLL_STATE_IDLE) {
                    mRecyclerView1.scrollBy(dx, dy);
                }
            }
        });
    }

    private void initRecyclerView1() {
        mRecyclerView1 = findViewById(R.id.recycler_view_1);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRecyclerView1.setLayoutManager(layoutManager);

        RecyclerViewAdapter mAdapter = new RecyclerViewAdapter(1);
        mRecyclerView1.setAdapter(mAdapter);
    }

    private void initRecyclerView2() {
        mRecyclerView2 = findViewById(R.id.recycler_view_2);
        StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(12, StaggeredGridLayoutManager.VERTICAL);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRecyclerView2.setLayoutManager(layoutManager);

        RecyclerViewAdapter mAdapter = new RecyclerViewAdapter(2);
        mRecyclerView2.setAdapter(mAdapter);
    }

    private class RecyclerViewAdapter extends RecyclerView.Adapter<MyVH> {
        private int id;

        public RecyclerViewAdapter(int id) {
            this.id = id;
        }

        @NonNull
        @Override
        public MyVH onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(getApplicationContext()).inflate(R.layout.rv_item, parent, false);
            return new MyVH(view);
        }

        @Override
        public void onBindViewHolder(@NonNull MyVH holder, int position) {
            holder.text1.setText("RecyclerView:" + id);
            holder.text2.setText(mItems.get(position) + "");

            switch (id) {
                case 1:
                    holder.text1.setBackgroundColor(Color.RED);
                    break;

                case 2:
                    holder.text1.setBackgroundColor(Color.BLUE);
                    break;
            }
        }

        @Override
        public int getItemCount() {
            return mItems.size();
        }
    }

    private class MyVH extends RecyclerView.ViewHolder {
        public TextView text1;
        public TextView text2;

        public MyVH(View itemView) {
            super(itemView);
            text1 = itemView.findViewById(R.id.text1);
            text1.setTextColor(Color.WHITE);
            text2 = itemView.findViewById(R.id.text2);
            text2.setTextColor(Color.DKGRAY);
        }
    }
}

相应布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view_1"
        android:layout_width="100dp"
        android:layout_height="match_parent" />

    <View
        android:layout_width="1px"
        android:layout_height="match_parent"
        android:background="#e0e0e0" />

    <HorizontalScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recycler_view_2"
            android:layout_width="1000dp"
            android:layout_height="match_parent" />
    </HorizontalScrollView>
</LinearLayout>

附录：
1，《Android若干条并排RecyclerView滑动实时联动》链接：https://blog.youkuaiyun.com/zhangphil/article/details/79925803 
2，《 Android dispatchTouchEvent检测多点触摸事件是否落入在某一个View区域内》链接：https://blog.youkuaiyun.com/zhangphil/article/details/80067150