pulltorefresh_demo上下拉刷新

本文介绍了一个基于Android平台实现上下拉刷新功能的示例项目。通过使用PullToRefreshListView控件结合自定义适配器和异步任务,实现了列表视图的数据加载与刷新。此外,还展示了如何设置头部和尾部布局的提示文字。

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布局文件:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:ptr="http://schemas.android.com/apk/res-auto"
    android:id="@+id/dl">


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

        <com.handmark.pulltorefresh.library.PullToRefreshListView
            android:layout_height="match_parent"
            android:layout_width="match_parent"
            android:id="@+id/lv"
            ptr:ptrDrawable="@drawable/default_ptr_flip"
            ptr:ptrAnimationStyle="flip"
            ptr:ptrHeaderBackground="#383838"

            ptr:ptrHeaderTextColor="#FFFFFF">




        </com.handmark.pulltorefresh.library.PullToRefreshListView>
    </RelativeLayout>



    <LinearLayout
        android:layout_width="200dp"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:background="#f00"
        android:layout_gravity="start"
        >

        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/img"/>
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/tv"

            />
        <ListView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:entries="@array/list">

        </ListView>


    </LinearLayout>


</android.support.v4.widget.DrawerLayout>

MainActivity:

package com.example.com.lianxiyuekaoti;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;

import com.example.com.lianxiyuekaoti.Adapter.Myadapter;
import com.example.com.lianxiyuekaoti.Bean.ReqBean;
import com.example.com.lianxiyuekaoti.Util.MyTask;
import com.example.com.lianxiyuekaoti.Util.NetStateUtil;
import com.google.gson.Gson;
import com.handmark.pulltorefresh.library.ILoadingLayout;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
;
    private Myadapter myadapter;
    private List<ReqBean.DataBean>list=new ArrayList<>();
    private int pageIndex=1;
    private int num=0;
    private PullToRefreshListView lv;
    private int type;
private  String urldata="http://www.93.gov.cn/93app/data.do?channelId=0&startNum="+num;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        lv = findViewById(R.id.lv);

        intoptlv();
        getlData();
    }



    public void getlData() {
        if(NetStateUtil.isConn(this)){
            MyTask myTask = new MyTask(new MyTask.Icallbacks() {

            @Override
            public void updateUiByjson(String jsonstr) {
                Gson gson = new Gson();
                ReqBean reqBean = gson.fromJson(jsonstr, ReqBean.class);
                //List<ReqBean.DataBean> data = reqBean.getData();
               /* Myadapter myadapter = new Myadapter(MainActivity.this, data);
                lv.setAdapter(myadapter);*/
               if(type==1){
                   list.clear();
               }
              list.addAll(reqBean.getData());
                setplvAdp();
            }
        });
        myTask.execute(urldata);
        lv.onRefreshComplete();
    }else {
            NetStateUtil.showNoNetWorkDlg(this);

        }
    }
    private void setplvAdp() {
if(myadapter==null){
    myadapter = new Myadapter(this,list);
    lv.setAdapter(myadapter);
}else{
    myadapter.notifyDataSetChanged();
}

    }
    private void intoptlv() {
        //设置模式
        lv.setMode(PullToRefreshBase.Mode.BOTH);

/*        //设置头尾布局显示的文字
        ILoadingLayout startLabels = lv.getLoadingLayoutProxy(true, false);
        startLabels.setPullLabel("下拉刷新");//第一次下拉时显示的文字
        startLabels.setRefreshingLabel("正在拉");//下拉的过程中显示的文字
        startLabels.setReleaseLabel("放开刷新");//不能在下拉时,显示的文字

        ILoadingLayout endLabels = lv.getLoadingLayoutProxy(false, true);
        //endLabels.setPullLabel("上拉刷新");
        endLabels.setRefreshingLabel("正在载入...");
        endLabels.setReleaseLabel("放开刷新...");*/

        lv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
            @Override
            public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {
                //下拉刷新
     type =1;
     num=0;
     urldata="http://www.93.gov.cn/93app/data.do?channelId=0&startNum="+num;
     getlData();
            }

            @Override
            public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {
                //上拉加载
                type=2;
                num +=20;

                urldata="http://www.93.gov.cn/93app/data.do?channelId=0&startNum="+num;
                getlData();
            }
        });

    }
}
//接口工具类:Mytask

package com.example.com.shangxialashuxin;

import android.os.AsyncTask;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * 使用AsyncTask+HttpURLConnection请求数据
 * Created by e531 on 2017/10/12.
 */
public class MyTask extends AsyncTask<String,Void,String> {

    //申请一个接口类对象
    private  Icallbacks icallbacks;

    //将无参构造设置成私有的,使之在外部不能够调用
    private MyTask(){}

    //定义有参构造方法
    public MyTask(Icallbacks icallbacks) {
        this.icallbacks = icallbacks;
    }

    @Override
    protected String doInBackground(String... params) {
        String str="";

        try {
             //使用HttpUrlConnection
            URL url=new URL(params[0]);
            HttpURLConnection connection=(HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setReadTimeout(5000);
            connection.setConnectTimeout(5000);

            if(connection.getResponseCode()==200){
                InputStream inputStream=connection.getInputStream();
                //调用工具类中的静态方法
                str=StreamToString.streamToStr(inputStream,"utf-8");
            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        }catch (IOException e){
            e.printStackTrace();
        }


        return str;
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);
        //解析,封装到bean,更新ui组件
        icallbacks.updateUiByjson(s);



    }
    //定义一个接口
    public interface Icallbacks{
        /**
         * 根据回传的json字符串,解析并更新页面组件
         * @param jsonstr
         */
        void updateUiByjson(String jsonstr);
    }
}
statemstring工具类中:

package com.example.com.shangxialashuxin;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;

/**
 * Created by e531 on 2017/10/12.
 */
public class StreamToString {

    public static String streamToStr(InputStream inputStream,String chartSet){

        StringBuilder builder=new StringBuilder();
        try {
            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream,chartSet));
            String con;
            while ((con=br.readLine())!=null){
                builder.append(con);
            }

            br.close();
            return builder.toString();


        } catch (Exception e) {
            e.printStackTrace();
        }


        return "";
    }
}
注:导入netutils包,还有适配器都一样:
适配器:
package com.example.com.shangxialashuxin;

import android.content.Context;
import android.graphics.Bitmap;
import android.os.AsyncTask;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;


import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;

/**
 * Created by 联想 on 2018/1/12.
 */

public class MyAdapter extends BaseAdapter {
    Context context;
    List<ReqBean.ResultBean.DataBean> data ;
    private final DisplayImageOptions options;
    public MyAdapter(Context context, List<ReqBean.ResultBean.DataBean> data) {
        this.context = context;
        this.data = data;

        options = new DisplayImageOptions.Builder()
                .cacheInMemory(true)//浣跨敤鍐呭瓨缂撳瓨
                .cacheOnDisk(true)//浣跨敤纾佺洏缂撳瓨
                .showImageOnLoading(R.mipmap.ic_launcher)//璁剧疆姝e湪涓嬭浇鐨勫浘鐗?
                .showImageForEmptyUri(R.mipmap.ic_launcher)//url涓虹┖鎴栬姹傜殑璧勬簮涓嶅瓨鍦ㄦ椂
                .showImageOnFail(R.mipmap.ic_launcher)//涓嬭浇澶辫触鏃舵樉绀虹殑鍥剧墖
                .bitmapConfig(Bitmap.Config.RGB_565)//璁剧疆鍥剧墖鑹插僵妯″紡 1px=2瀛楄妭
                .imageScaleType(ImageScaleType.EXACTLY)//璁剧疆鍥剧墖鐨勭缉鏀炬ā寮?
                .displayer(new RoundedBitmapDisplayer(100))//璁剧疆鍦嗚 30浠h〃鍗婂緞 鑷畾涔?
                .build();

    }


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

    @Override
    public Object getItem(int i) {
        return data.get(i);
    }

    @Override
    public long getItemId(int i) {
        return i;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder holder;
        if (view==null){
            view=View.inflate(context, R.layout.connectionfriview,null);
            holder=new ViewHolder();
            holder.tv=view.findViewById(R.id.tv);
            holder.img=view.findViewById(R.id.img);
            view.setTag(holder);
        }else{
            holder= (ViewHolder) view.getTag();

        }
        holder.tv.setText(data.get(i).getTitle());

       // ImageLoader.getInstance().displayImage(data.get(i).getThumbnail_pic_s(),holder.img,options);
       /* mytask mytask = new mytask(holder.img);
        mytask.execute()*/
        return view;
    }

    private class ViewHolder{
        TextView tv;
        ImageView img;
    }
   /* class mytask extends AsyncTask<String,Void,String>{

        private  ImageView img;

    *//*    public mytask(ImageView img) {
            this.img=img;
        }

        @Override
        protected String doInBackground(String... strings) {
            try {
                URL url = new URL(strings[0]);
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setConnectTimeout();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {


            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
        }
    }*/
}



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