下拉·刷新

package com.example.a1.app_demo;

import android.os.AsyncTask;
import android.support.annotation.NonNull;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

import com.google.gson.Gson;

import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.math.MathContext;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import me.maxwin.view.XListView;

public class MainActivity extends AppCompatActivity {
private XListView contexts;
private MyActivity myActivity;
String aur="http://api.expoon.com/AppNews/getNewsList/type/1/p?";
private List<User.DataBean> list=new ArrayList<>();
private List<User.DataBean> data;
private int page;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DrawerLayout draw=findViewById(R.id.draw);
contexts=findViewById(R.id.contents);
myActivity=new MyActivity(this,list);
contexts.setAdapter(myActivity);
draw.addDrawerListener(new DrawerLayout.DrawerListener() {
@Override
public void onDrawerSlide(@NonNull View view, float v) {

        }

        @Override
        public void onDrawerOpened(@NonNull View view) {

        }

        @Override
        public void onDrawerClosed(@NonNull View view) {

        }

        @Override
        public void onDrawerStateChanged(int i) {

        }
    });
    //
    contexts.setPullLoadEnable(true);
    contexts.setXListViewListener(new XListView.IXListViewListener() {
        @Override
        public void onRefresh() {
            page=1;
            indata();
        }

        @Override
        public void onLoadMore() {
            indata();
        }
    });
    page=1;
    indata();

}
private void  indata(){
    new lian().execute(aur+page);
}
class lian extends AsyncTask<String,Void,ArrayList<User.DataBean>>{

    @Override
    protected ArrayList<User.DataBean> doInBackground(String... strings) {
        try {
            URL url=new URL(strings[0]);
            HttpURLConnection urlConnection= (HttpURLConnection) url.openConnection();
            if (urlConnection.getResponseCode()==200){
                final InputStream inputStream = urlConnection.getInputStream();
                Gson gson=new Gson();
                final User user = gson.fromJson(new InputStreamReader(new BufferedInputStream(inputStream)), User.class);
                final List<User.DataBean> data = user.getData();
                return (ArrayList<User.DataBean>) data;
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(ArrayList<User.DataBean> dataBeans) {
        super.onPostExecute(dataBeans);
       if (data==null){
           contexts.stopLoadMore();
           contexts.stopRefresh();
       }if (page==1){
           myActivity.setList(dataBeans);
        }else{
           list.addAll(dataBeans);
        }
        contexts.stopRefresh();
        contexts.stopLoadMore();
        page++;



    }
}

}

MyActivity

package com.example.a1.app_demo;

import android.content.Context;
import android.view.LayoutInflater;
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 java.util.ArrayList;
import java.util.IllegalFormatCodePointException;
import java.util.List;

public class MyActivity extends BaseAdapter {
private Context context;
private List<User.DataBean> list;

public MyActivity(Context context, List<User.DataBean> list) {
    this.context = context;
    this.list=list;
}


public void setList(List<User.DataBean> List){
    if (list!=null){
        this.list=list;
    }
    notifyDataSetChanged();
}
public void addDatas(List<User.DataBean> list1){
    if (list1!=null){
        list.addAll(list1);
    }
    notifyDataSetChanged();
}

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

@Override
public Object getItem(int position) {
    return list.get(position);
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder viewHolder;
    if (convertView==null){
        viewHolder=new ViewHolder();
        convertView=LayoutInflater.from(context).inflate(R.layout.pop,parent,false);
        viewHolder.image=convertView.findViewById(R.id.image);
        viewHolder.name=convertView.findViewById(R.id.name);
        viewHolder.price=convertView.findViewById(R.id.price);
        convertView.setTag(viewHolder);
    }else{
        viewHolder= (ViewHolder) convertView.getTag();
    }
    viewHolder.name.setText(list.get(position).getNews_summary());
    viewHolder.price.setText(list.get(position).getNews_title());
    final DisplayImageOptions options = new DisplayImageOptions.Builder().build();
    ImageLoader.getInstance().displayImage(list.get(position).getPic_url(),viewHolder.image,options);
    return convertView;
}
class ViewHolder{
    TextView name,price;
    ImageView image;
}

}