Android RecycleView上拉加载

来源：互联网发布：vj软件resolume 编辑：程序博客网时间：2024/05/18 00:26

上拉加载的思路就是实现OnScrollListener

<pre name="code" class="java"> mRecyclerView.addOnScrollListener(new OnScrollListener() {            @Override            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {                super.onScrollStateChanged(recyclerView, newState);                if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem + 1 == list.size()) {//这里进行加载数据操作                                    }            }            @Override            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {                super.onScrolled(recyclerView, dx, dy);                lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();            }        });

1、当RecycleView当前可见项的最后一个+1=列表的长度时候。比如列表长度为10，当前可见（从0开始计算）的最后一个是9，就是最后一个了。

2、newState是一个什么东西？

public void stopScroll() {        setScrollState(SCROLL_STATE_IDLE);        stopScrollersInternal();    }

   <span style="font-size:18px;">这是来自RecyclerView的代码片段，从上面可以看出。当RecyclerView停止刷新（上拉或者下拉）的时候设置RecyclerView的状态为SCROLL_STATE_IDLE。当用户停止刷新并且当前可见的item是最后一个就显示上拉加载</span>

<span style="font-size:18px;"></span>

<span style="font-size:18px;"></span>

<span style="font-size:18px;">activity代码</span>

<span style="font-size:18px;"></span><pre name="code" class="java">package com.qd.wangxm.recycleviewloadmore;import android.os.Bundle;import android.os.Handler;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.GridLayoutManager;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.RecyclerView.OnScrollListener;import android.util.Log;import android.widget.Toast;import com.qd.wangxm.recycleviewloadmore.adapter.MyAdapter;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;    private MyAdapter mAdapter;    private LinearLayoutManager linearLayoutManager;    private int lastVisibleItem;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        linearLayoutManager = new LinearLayoutManager(this);        final List<String> list = new ArrayList<>();        for (int i = 0; i < 10; i++) {            list.add("第" + i + "个数据项");        }        mRecyclerView = (RecyclerView) findViewById(R.id.rv_list);        mAdapter = new MyAdapter(list, this);        RecyclerView.LayoutManager manager = new GridLayoutManager(this, 1, GridLayoutManager.VERTICAL, false);        mRecyclerView.setLayoutManager(linearLayoutManager);        mRecyclerView.setAdapter(mAdapter);        mRecyclerView.addOnScrollListener(new OnScrollListener() {            @Override            public void onScrollStateChanged(RecyclerView recyclerView, int newState) {                super.onScrollStateChanged(recyclerView, newState);                if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem  == list.size() && mAdapter.getFooterType() == MyAdapter.FOOTER_LOAD_MORE) {                    mAdapter.loading();                    //在这里加载数据                    new Handler().postDelayed(new Runnable() {                        @Override                        public void run() {                            List<String> newDatas = new ArrayList<String>();                            for (int i = 0; i < 5; i++) {                                int index = i + 1;                                newDatas.add("more item" + index);                            }                            list.addAll(newDatas);                            //加载完数据调用addItem                            mAdapter.addItem(list);                        }                    }, 1000);                }            }            @Override            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {                super.onScrolled(recyclerView, dx, dy);                lastVisibleItem = linearLayoutManager.findLastVisibleItemPosition();            }        });    }    public void showToast(String msg) {        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();        Log.e("-------------", msg);    }}

</pre>adapter代码<pre>

<span style="font-size:18px;"></span><pre name="code" class="java">package com.qd.wangxm.recycleviewloadmore.adapter;import android.content.Context;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;import com.qd.wangxm.recycleviewloadmore.R;import java.util.ArrayList;import java.util.List;/** * Created by WangXM on 2016/5/30. */public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {    private static final int TYPE_ITEM = 0;  //普通Item View    private static final int TYPE_FOOTER = 1;  //顶部FootView    public static final int FOOTer_LOADING=1;    public static final int FOOTER_LOAD_MORE=2;    public static final int FOOTER_NO_ITEM=0;    private int footerType=FOOTER_LOAD_MORE;    private List<String> mList = new ArrayList<>();    private Context mContext;    public MyAdapter(List<String> list, Context context) {        mList = list;        mContext = context;    }    public int getFooterType(){        return footerType;    }    @Override    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        if (viewType == TYPE_ITEM) {            View view = LayoutInflater.from(mContext).inflate(R.layout.item_myadapter, parent, false);            ItemHolder holder = new ItemHolder(view);            return holder;        } else {            View view = LayoutInflater.from(mContext).inflate(R.layout.item_foot, parent, false);            FootHolder holder = new FootHolder(view);            return holder;        }    }    @Override    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {        if (position < mList.size()) {            ((ItemHolder) holder).tvContent.setText(mList.get(position));        } else {            if (footerType==FOOTER_LOAD_MORE)                ((FootHolder) holder).tvContent.setText("上拉加载更多数据");            else if (footerType==FOOTER_NO_ITEM)                ((FootHolder) holder).tvContent.setText("已经是最后一页，没有数据了");            else                ((FootHolder) holder).tvContent.setText("正在加载更多数据。。。");        }    }    @Override    public int getItemCount() {        return mList.size() + 1;    }    @Override    public int getItemViewType(int position) {        if (position < mList.size()) {            return TYPE_ITEM;        } else {            return TYPE_FOOTER;        }    }    public void loading(){        this.footerType=FOOTer_LOADING;        notifyDataSetChanged();    }    public void  addItem(List<String> list){//        this.mList.clear();//        mList.addAll(list);        this.footerType=FOOTER_LOAD_MORE;        notifyDataSetChanged();    }    public void  addItemNoNext(List<String> list){        this.mList.clear();        mList.addAll(list);        this.footerType=FOOTER_NO_ITEM;        notifyDataSetChanged();    }    class ItemHolder extends RecyclerView.ViewHolder {        public TextView tvContent;        public ItemHolder(View itemView) {            super(itemView);            tvContent = (TextView) itemView.findViewById(R.id.tv_context);        }    }    class FootHolder extends RecyclerView.ViewHolder {        public TextView tvContent;        public FootHolder(View itemView) {            super(itemView);            tvContent = (TextView) itemView.findViewById(R.id.tv_context);        }    }}

BaseAdapter见下文 http://blog.csdn.net/jing85432373/article/details/51682156

</pre><pre code_snippet_id="1702488" snippet_file_name="blog_20160531_4_7186047" name="code" class="java">

</pre><pre>

1 1