当有网络时，进入页面使用网络加载数据，并将列表数据保存到数据库，当没有网络时，将从数据库读取数据并做展示

创建数据库

package com.example.mnyk;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class OpenHolper extends SQLiteOpenHelper {


    public OpenHolper(Context context) {
        //基本参数  数据库名 版本号
        super(context, "lz",null,1);
    }

    //创建数据库
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        /*
        CREATE TABLE "" (
    id         INTEGER PRIMARY KEY AUTOINCREMENT,
    title      VARCHAR,
    image      VARCHAR,
    imagetwo   VARCHAR,
    imagethree VARCHAR);
         */
        sqLiteDatabase.execSQL("create table dz(id INTEGER PRIMARY KEY AUTOINCREMENT,title VARCHAR,image VARCHAR,imagetwo VARCHAR,imagethree VARCHAR)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }
}

数据库的具体操作 增删改查

package com.example.mnyk;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

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

//进行数据库增删改查
public class SqlLite {

    //获取数据库对象
    SQLiteDatabase db;

    public SqlLite(Context context) {
        this.db = new OpenHolper(context).getWritableDatabase();
    }

    //添加
    public void add(DataItem.DataBean data){
     db.execSQL("insert into dz (title,image,imagetwo,imagethree) values (?,?,?,?);",new String[]{data.getTitle(),data.getThumbnail_pic_s(),data.getThumbnail_pic_s02(),data.getThumbnail_pic_s03()});
    }
    //删除
    public void delete(DataItem.DataBean data){

    }
    //查询
    public List<DataItem.DataBean> select(){
        List<DataItem.DataBean> list = new ArrayList<>();
        Cursor result = db.query("dz", new String[]{"title", "image", "imagetwo", "imagethree"}, null, null, null, null, null);
        while (result.moveToNext()){
            DataItem.DataBean item = new DataItem.DataBean();
            item.setTitle(result.getString(0));
            item.setThumbnail_pic_s(result.getString(1));
            item.setThumbnail_pic_s02(result.getString(2));
            item.setThumbnail_pic_s03(result.getString(3));
            list.add(item);
        }
        return list;
    }
}

判断是否有网络
当有网络时，进入页面使用网络加载数据，并将列表数据保存到数据库，当没有网络时，将从数据库读取数据并做展示

package com.example.mnyk;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;
import android.widget.Toast;

import com.example.xlistview.me.maxwin.view.XListView;
import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

public class HotFragment extends android.support.v4.app.Fragment {

    private View view;
    private XListView lv;
    private ArrayList<DataItem> dataItems;
    private MAdapter mAdapter;
    private String url = "http://www.xieast.com/api/news/news.php?count=10&page=";
    private int page = 1;
    private SqlLite sqlLite;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = View.inflate(getActivity(), R.layout.fragment_hot, null);
        //获取资源id
        lv = (XListView) view.findViewById(R.id.lv);

        dataItems = new ArrayList<DataItem>();
        mAdapter = new MAdapter(getActivity());

        //设置XListView监听
        lv.setXListViewListener(new XListView.IXListViewListener() {
            @Override
            public void onRefresh() {
                //下拉刷新
                page = 1;
                initData(page);
            }

            @Override
            public void onLoadMore() {
                //上拉加载
                page = page+1;
                initData(page);
            }
        });

        //注意 : 一定要写上这句话 否则不能实现加载更多
        //可加载
        lv.setPullLoadEnable(true);
        //初始化网络数据
        initData(page);

        lv.setAdapter(mAdapter);
        return view;
    }

    //加载网络数据
    private void initData(final int page) {
        //如果查询为空 则创建对象
        if (sqlLite == null){
            sqlLite = new SqlLite(getActivity());
        }

        //如果没有网络 就从数据库中加载
       if(!Network()){
           List<DataItem.DataBean> result = sqlLite.select();
           mAdapter.setDatas(result);
           Toast.makeText(getActivity(),"网络消失了",Toast.LENGTH_SHORT).show();
           lv.stopRefresh();
           lv.stopLoadMore();
           return;
       }

        new AsyncTask<String, Void, List<DataItem.DataBean>>() {
            @Override
            protected List<DataItem.DataBean> doInBackground(String... strings) {

                DataItem dataItem = Util.ResponseBean(strings[0],DataItem.class);
                return dataItem.getData();
            }

            @Override
            protected void onPostExecute(List<DataItem.DataBean> dataBeans) {
                if (dataBeans == null){
                    Toast.makeText(getActivity(),"请求网络数据失败",Toast.LENGTH_SHORT).show();
                    return;
                }

                //循环遍历每一条数据 添加到数据库
                for (int i = 0 ; i < dataBeans.size(); i++){
                    sqlLite.add(dataBeans.get(i));
                }


                if (page == 1){
                    mAdapter.setDatas(dataBeans);
                }else {
                    mAdapter.addDatas(dataBeans);
                }

                lv.stopLoadMore();
                lv.stopRefresh();

            }
        }.execute(url+page);

    }

    //判断网络
    public Boolean Network(){
        //获取网络连接管理类
        ConnectivityManager systemService = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo info = systemService.getActiveNetworkInfo();
        return info != null && info.isAvailable();
    }


}