RecyclerView里嵌套ViewPager，滚动RecyclerView时，记住之前ViewPager滑动后的位置

最新推荐文章于 2023-10-17 13:18:48 发布

原创最新推荐文章于 2023-10-17 13:18:48 发布 · 8.4k 阅读

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#viewpager #RcycleView #嵌套

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本文介绍了解决在ListView或RecyclerView中嵌套使用ViewPager时出现的滑动冲突问题的方法。通过使用一个Map来记录ViewPager在RecyclerView中的位置及其当前页面，确保了在滑动时能够正确显示上一次的状态。

如果是ListView里嵌套ViewPager的话，首先要考虑的是竖向滑动和横向冲突的问题，RecyclerView的话，不用考虑此问题

方法：

准备一个map来存储你滑动过的ViewPager所在的RcyclerView中的位置和你滑动ViewPager后，ViewPager所显示的内容的位置
RcyclerView每次显示其item时，使其内部的ViewPager，按照map里保存好的信息，来显示指定位置的ViewPager的位置（RcyclerView的onBindViewHolder方法里的内实现）
每次ViewPager滑动后，要保存你滑动过的ViewPager所在的RcyclerView中的位置和你滑动ViewPager后，ViewPager所显示的内容的位置（setOnPageChangeListener的onPageSelected方法内实现）

关键代码：

     Map<Integer,Integer> map=new HashMap();

     @Override
        public void onBindViewHolder(final MyVH holder, int position) {
            holder.tv.setText(list.get(position));
            mPagerAdapter = new MyPagerAdapter(context, list);
            holder.viewpager.setAdapter(mPagerAdapter);

            Iterator iter = map.entrySet().iterator();
            while (iter.hasNext()) {
                Map.Entry entry = (Map.Entry) iter.next();
                int key = (int) entry.getKey();
                int val = (int) entry.getValue();
                if (position==key){
                    holder.viewpager.setCurrentItem(val);
                }
            }

            holder.viewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                @Override
                public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

                }

                @Override
                public void onPageSelected(int position) {
                    int recyclerPosition = holder.getLayoutPosition();
                    map.put(recyclerPosition,position);
                }

                @Override
                public void onPageScrollStateChanged(int state) {

                }
            });



        }

全部代码：

package com.github.c.recycleviewhorizonalscroll;

import android.content.Context;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private List<String> list;
    private MyAdapter mAdapter;
    Map<Integer,Integer> map=new HashMap();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        list = new ArrayList<>();
        for (int i = 0; i < 9; i++) {
            list.add("这是item" + i);
        }


        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        mAdapter = new MyAdapter(this, list);
        LinearLayoutManager manager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
        mRecyclerView.setLayoutManager(manager);
        mRecyclerView.setAdapter(mAdapter);

    }


    class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyVH> {
        private Context context;
        private List<String> list;
        private MyPagerAdapter mPagerAdapter;


        public MyAdapter(Context context, List<String> list) {
            this.context = context;
            this.list = list;
        }

        @Override
        public MyVH onCreateViewHolder(ViewGroup parent, int viewType) {
            LayoutInflater inflater = LayoutInflater.from(context);
            View view = inflater.inflate(R.layout.item, parent, false);


            return new MyVH(view);
        }

        @Override
        public void onBindViewHolder(final MyVH holder, int position) {
            holder.tv.setText(list.get(position));
            mPagerAdapter = new MyPagerAdapter(context, list);
            holder.viewpager.setAdapter(mPagerAdapter);

            Iterator iter = map.entrySet().iterator();
            while (iter.hasNext()) {
                Map.Entry entry = (Map.Entry) iter.next();
                int key = (int) entry.getKey();
                int val = (int) entry.getValue();
                if (position==key){
                    holder.viewpager.setCurrentItem(val);
                }
            }

            holder.viewpager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                @Override
                public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

                }

                @Override
                public void onPageSelected(int position) {
                    int recyclerPosition = holder.getLayoutPosition();
                    map.put(recyclerPosition,position);
                }

                @Override
                public void onPageScrollStateChanged(int state) {

                }
            });



        }

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

        class MyVH extends RecyclerView.ViewHolder {

            private TextView tv;
            private ViewPager viewpager;
            View itemView;

            public MyVH(View itemView) {
                super(itemView);
                this.itemView = itemView;
                tv = (TextView) itemView.findViewById(R.id.tv);
                viewpager = (ViewPager) itemView.findViewById(R.id.viewpager);

            }
        }
    }


    class MyPagerAdapter extends PagerAdapter {
        private Context context;
        private List<String> list;


        public MyPagerAdapter(Context context, List<String> list) {
            this.context = context;
            this.list = list;
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {

            View view = View.inflate(context, R.layout.item_item, null);
            TextView tv_inner = (TextView) view.findViewById(R.id.tv_inner);
            tv_inner.setText(list.get(position));
            container.addView(view);
            return view;
        }

        @Override
        public int getCount() {
            return list.size();
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == object;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView((View) object);
        }


    }
}