PullToRefreshListView上拉加载下拉刷新

Posted 2020-08-10 巫山老妖

说明：此项目使用studio完成的、需要导入library作为依赖，使用了xuitls获得网络请求、使用Pull解析了XML



//布局文件

<com.handmark.pulltorefresh.library.PullToRefreshListView
    android:id="@+id/list_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

package com.bw.com.yuekao1;

import android.content.Context;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.util.Xml;
import android.widget.ListView;
import android.widget.Toast;

import com.bw.com.yuekao1.com.bw.yuekao1.bean.News;
import com.bw.com.yuekao1.com.bw.yuekao1.bean.com.bw.yuekao1.adapter.MyAdapter;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;
import com.lidroid.xutils.HttpUtils;
import com.lidroid.xutils.exception.HttpException;
import com.lidroid.xutils.http.ResponseInfo;
import com.lidroid.xutils.http.callback.RequestCallBack;
import com.lidroid.xutils.http.client.HttpRequest;


import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    //封装结合
    private List<News> news=new ArrayList<News>();
    //PullToRefreshListView用于上拉加载、上拉刷新
    private PullToRefreshListView lv;
    private MyAdapter adapter;
    //定义一个页数，分页加载
    private int ye=1;
    //使用Handler更新UI
    private Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case 0:
                    //获得线程发来的数据
                    String text=(String) msg.obj;
                    //XML解析
                    toXml(text);
                    break;

                default:
                    break;
            }
        }
    };


    private void toXml(String text) {
        News newss=null;
        try {
            //将读取到的结果码   添加到XML里面
            XmlPullParser Parser = Xml.newPullParser();
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(text.getBytes());
           Parser.setInput(byteArrayInputStream,"utf-8");
            //通过parse获得项目类型      相当于文件里面的属性吧
            int eventType = Parser.getEventType();
            //判断
            while ((eventType != XmlPullParser.END_DOCUMENT)) {
                String name = Parser.getName();
                switch (eventType) {
                    case XmlPullParser.START_TAG:
                        if (name.equals("news")) {
                            newss = new News();
                        } else if (name.equals("id")) {
                            String id = Parser.nextText();
                            newss.setId(id);
                        } else if (name.equals("title")) {
                            String title = Parser.nextText();
                            newss.setTitle(title);
                        } else if (name.equals("body")) {
                            String body = Parser.nextText();
                            newss.setBody(body);
                        } else if (name.equals("commentCount")) {
                            String commentCount = Parser.nextText();
                            newss.setCommentCount(commentCount);
                        }
                        else if (name.equals("author")) {
                            String author = Parser.nextText();
                            newss.setAuthor(author);
                        }
                        else if (name.equals("pubDate")) {
                            String pubDate = Parser.nextText();
                            newss.setPubDate(pubDate);
                        }
                        break;
                    case XmlPullParser.END_TAG:
                        if (name.equals("news")) {
                            news.add(newss);
                            //更新适配器
                            if (adapter == null) {
                                adapter = new MyAdapter(news,this);
                                lv.setAdapter(adapter);
                            } else {
                                adapter .notifyDataSetChanged();
                            }
                        }
                        break;
                    default:
                        break;
                }
                eventType=Parser.next();
            }
        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    };


//-------------onCreate中--------------
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //找到PullToRefreshListView的控件
        lv= (PullToRefreshListView) findViewById(R.id.list_view);
        //获得网络数据-传一个页数
        huodeshuju(ye);
        //设置适配器
        adapter = new MyAdapter(news,this);
        lv.setAdapter(adapter);
        //设置PullToRefreshListView的模式，BOTH时，既可以刷新也可以加载
        lv.setMode(PullToRefreshBase.Mode.BOTH);
        //设置刷新的方法
        lv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
            @Override//下拉刷新
            public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {
                //重新定义为第一页
                ye=1;
                Toast.makeText(MainActivity.this,""+ye,Toast.LENGTH_SHORT).show();
               //获得数据
             huodeshuju(ye);
                //刷新适配器
                adapter.notifyDataSetChanged();
                //创建一个方法结束刷新
                new FinishRefresh().execute();
            }

            @Override//上拉加载更多
            public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {
             //使页数加1
                ye++;
                Toast.makeText(MainActivity.this,""+ye,Toast.LENGTH_SHORT).show();
                huodeshuju(ye);
                adapter.notifyDataSetChanged();
                new FinishRefresh().execute();
            }
        });
    }

//使用的是HttpUtils请求网络数据——需要导入一个xuitls.jar包
    private void huodeshuju(int ye) {
        //创建HttpUtils
        HttpUtils httpUtils=new HttpUtils();
        //发送GET请求
        httpUtils.send(HttpRequest.HttpMethod.GET, "http://www.oschina.net/action/api/news_list?catalog=1&pageIndex="+ye+"&pageSize=20", new RequestCallBack<String>() {
            @Override//请求成功的方法
            public void onSuccess(ResponseInfo<String> responseInfo) {
                String str=responseInfo.result;
                Message message=new Message();
                message.what=0;
                message.obj=str;
                handler.sendMessage(message);
            }
         //请求失败的方法
            @Override
            public void onFailure(HttpException e, String s) {

            }
        });
    }

    //完成刷新的方法
    private class FinishRefresh extends AsyncTask<Void, Void, Void> {
        @Override
        protected Void doInBackground(Void... params) {
            return null;
        }

        @Override
        protected void onPostExecute(Void result){
            //刷新完成
            lv.onRefreshComplete();
        }
    }
}