[移动开发]APP的常规流程

一,首先确定布局和基本权限

二,当开始在主Activity中开始写代码的时候,首先找所需的控件,然后思考本Activity需不需要开启子线程.

三,书写子线程代码

示例工程

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.mi.MainActivity">

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

</LinearLayout>

items.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/img"
        android:layout_width="100dp"
        android:layout_height="100dp" />

    <TextView
        android:id="@+id/txt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

MainActivity.java

package com.example.mi;

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

import com.example.mi.bean.DateBean;
import com.example.mi.utils.JsonDao;
import com.example.mi.utils.NetStateUtil;
import com.google.gson.Gson;
import com.handmark.pulltorefresh.library.LoadingLayoutProxy;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

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

public class MainActivity extends AppCompatActivity {

    private PullToRefreshListView plv;
    private int oderType = 1;
    private int pageIndex = 1;
    private List <DateBean.NewslistBean> dataAll=new ArrayList <>();
    private MyAdapter adapter;
    private String url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
    private JsonDao jsonDao = new JsonDao(this);
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            List <DateBean.NewslistBean> list = (List <DateBean.NewslistBean>)msg.obj;
            showData(list);
        }
    };

    private void showData(List <DateBean.NewslistBean> list) {
        if (oderType==1)
        {
            dataAll.clear();
        }
        dataAll.addAll(list);
        setPlvAdapter();
        plv.onRefreshComplete();
    }

    private void setPlvAdapter() {
        if (adapter==null)
        {
            adapter=new MyAdapter(MainActivity.this,dataAll);
            plv.setAdapter(adapter);
        }else {
            adapter.notifyDataSetChanged();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        plv = findViewById(R.id.plv);

        initPlv();

        requestNetData();

    }

    private void requestNetData() {
        //判断网络是否连接
        if (NetStateUtil.isConn(this)){
            openThread();
        }else {
            NetStateUtil.showNoNetWorkDlg(this);
            //吐司提示
            Toast.makeText(this,"现在没有网络，请稍后重试！",Toast.LENGTH_SHORT).show();
            //展示本地数据
            String s = jsonDao.select(url);
            Gson gson = new Gson();
            showData(gson.fromJson(s,DateBean.class).getNewslist());

        }
    }

    public void openThread(){
        new Thread(){
            @Override
            public void run() {
                try {
                    URL url1=new URL(url);
                    HttpURLConnection urlConnection = (HttpURLConnection)url1.openConnection();
                    urlConnection.setReadTimeout(5000);
                    urlConnection.setConnectTimeout(5000);
                    urlConnection.setRequestMethod("GET");
                    if (urlConnection.getResponseCode()==200)
                    {
                        InputStream inputStream = urlConnection.getInputStream();
                        String s = streamToString(inputStream);
                        jsonDao.insertData(url,s);
                        Gson gson = new Gson();
                        DateBean dateBean = gson.fromJson(s, DateBean.class);
                        List <DateBean.NewslistBean> newslist = dateBean.getNewslist();
                        Message mes = Message.obtain();
                        mes.obj=newslist;
                        handler.sendMessage(mes);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    private String streamToString(InputStream inputStream) {
        StringBuilder stringBuilder = new StringBuilder();
        String str;
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        try {
            while ((str=bufferedReader.readLine())!=null)
            {
                stringBuilder.append(str);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return  stringBuilder.toString();
    }

    private void initPlv() {
        plv.setMode(PullToRefreshBase.Mode.BOTH);
        //设置下拉提示文字
        LoadingLayoutProxy layoutProxy = (LoadingLayoutProxy) plv.getLoadingLayoutProxy(true, false);
        //下拉的时候显示的文本
        layoutProxy.setPullLabel("继续拉,对,继续,拉,拉,拉");
        //放开刷新的时候显示的文本
        layoutProxy.setReleaseLabel("松开你就会发现一件神奇的事情");
        //执行刷新的时候显示的文本
        layoutProxy.setRefreshingLabel("哈哈哈哈哈,神奇不?");

        //设置上拉提示文字
        LoadingLayoutProxy layoutProxy1 = (LoadingLayoutProxy) plv.getLoadingLayoutProxy(false, true);
        //上拉的时候显示的文本
        layoutProxy1.setPullLabel("继续上拉,加载更多~");
        //放开刷新的时候显示的文本
        layoutProxy1.setReleaseLabel("松开加载");
        //执行刷新的时候显示的文本
        layoutProxy1.setRefreshingLabel("正在加载...");


        plv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2 <ListView>() {
            @Override
            public void onPullDownToRefresh(PullToRefreshBase <ListView> pullToRefreshBase) {
                oderType=1;
                pageIndex=1;
                url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
                requestNetData();
            }

            @Override
            public void onPullUpToRefresh(PullToRefreshBase <ListView> pullToRefreshBase) {
                oderType=2;
                pageIndex++;
                url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
                requestNetData();
            }
        });
    }

    
}

package com.example.mi;

import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Adapter;
import android.widget.ListView;
import android.widget.Toast;

import com.example.mi.bean.DateBean;
import com.example.mi.utils.JsonDao;
import com.example.mi.utils.NetStateUtil;
import com.google.gson.Gson;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

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

public class MainActivity extends AppCompatActivity {

    private PullToRefreshListView plv;
    private int oderType = 1;
    private int pageIndex = 1;
    private List <DateBean.NewslistBean> dataAll=new ArrayList <>();
    private MyAdapter adapter;
    private String url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
    private JsonDao jsonDao = new JsonDao(this);
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            List <DateBean.NewslistBean> list = (List <DateBean.NewslistBean>)msg.obj;
            showData(list);
        }
    };

    private void showData(List <DateBean.NewslistBean> list) {
        if (oderType==1)
        {
            dataAll.clear();
        }
        dataAll.addAll(list);
        setPlvAdapter();
        plv.onRefreshComplete();
    }

    private void setPlvAdapter() {
        if (adapter==null)
        {
            adapter=new MyAdapter(MainActivity.this,dataAll);
            plv.setAdapter(adapter);
        }else {
            adapter.notifyDataSetChanged();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        plv = findViewById(R.id.plv);

        initPlv();

        requestNetData();

    }

    private void requestNetData() {
        //判断网络是否连接
        if (NetStateUtil.isConn(this)){
            openThread();
        }else {
            NetStateUtil.showNoNetWorkDlg(this);
            //吐司提示
            Toast.makeText(this,"现在没有网络，请稍后重试！",Toast.LENGTH_SHORT).show();
            //展示本地数据
            String s = jsonDao.select(url);
            Gson gson = new Gson();
            showData(gson.fromJson(s,DateBean.class).getNewslist());

        }
    }

    public void openThread(){
        new Thread(){
            @Override
            public void run() {
                try {
                    URL url1=new URL(url);
                    HttpURLConnection urlConnection = (HttpURLConnection)url1.openConnection();
                    urlConnection.setReadTimeout(5000);
                    urlConnection.setConnectTimeout(5000);
                    urlConnection.setRequestMethod("GET");
                    if (urlConnection.getResponseCode()==200)
                    {
                        InputStream inputStream = urlConnection.getInputStream();
                        String s = streamToString(inputStream);
                        jsonDao.insertData(url,s);
                        Gson gson = new Gson();
                        DateBean dateBean = gson.fromJson(s, DateBean.class);
                        List <DateBean.NewslistBean> newslist = dateBean.getNewslist();
                        Message mes = Message.obtain();
                        mes.obj=newslist;
                        handler.sendMessage(mes);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

    private String streamToString(InputStream inputStream) {
        StringBuilder stringBuilder = new StringBuilder();
        String str;
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
        try {
            while ((str=bufferedReader.readLine())!=null)
            {
                stringBuilder.append(str);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return  stringBuilder.toString();
    }

    private void initPlv() {
        plv.setMode(PullToRefreshBase.Mode.BOTH);
        plv.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2 <ListView>() {
            @Override
            public void onPullDownToRefresh(PullToRefreshBase <ListView> pullToRefreshBase) {
                oderType=1;
                pageIndex=1;
                url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
                requestNetData();
            }

            @Override
            public void onPullUpToRefresh(PullToRefreshBase <ListView> pullToRefreshBase) {
                oderType=2;
                pageIndex++;
                url="https://api.tianapi.com/wxnew/?key=48a7d7193e11bd2dd4a683b6e2f90a4f&num=10&page="+pageIndex;
                requestNetData();
            }
        });
    }

    
}

MyAdapter.java

package com.example.mi;

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

import com.example.mi.bean.DateBean;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;

import java.util.List;

/**
 * Created by Administrator on 2018/3/31.
 */

public class MyAdapter extends BaseAdapter {

    private Context context;
    private List<DateBean.NewslistBean> list;
    private DisplayImageOptions options;

    public MyAdapter(Context context, List <DateBean.NewslistBean> list) {
        this.context = context;
        this.list = list;
        options=new DisplayImageOptions.Builder()
                .cacheInMemory(true)//使用内存缓存
                .cacheOnDisk(true)//使用磁盘缓存
                .showImageOnLoading(R.mipmap.ic_launcher_round)//设置正在下载的图片
                .showImageForEmptyUri(R.mipmap.ic_launcher_round)//url为空或请求的资源不存在时
                .showImageOnFail(R.mipmap.ic_launcher_round)//下载失败时显示的图片
                .bitmapConfig(Bitmap.Config.RGB_565)//设置图片色彩模式
                .imageScaleType(ImageScaleType.EXACTLY)//设置图片的缩放模式
                .build();
    }

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

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

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        ViewHolder viewHolder;
        if (view==null)
        {
            view=View.inflate(context,R.layout.items,null);
            viewHolder=new ViewHolder();
            viewHolder.img = view.findViewById(R.id.img);
            viewHolder.txt = view.findViewById(R.id.txt);
            view.setTag(viewHolder);
        }else {
            viewHolder=(ViewHolder)view.getTag();
        }

        ImageLoader.getInstance().displayImage(list.get(i).getPicUrl(),viewHolder.img,options);
        viewHolder.txt.setText(list.get(i).getTitle());

        return view;
    }

    class ViewHolder{
        ImageView img;
        TextView txt;
    }
}

package com.example.mi;

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

import com.example.mi.bean.DateBean;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;

import java.util.List;

/**
 * Created by Administrator on 2018/3/31.
 */

public class MyAdapter extends BaseAdapter {

    private Context context;
    private List<DateBean.NewslistBean> list;
    private DisplayImageOptions options;

    public MyAdapter(Context context, List <DateBean.NewslistBean> list) {
        this.context = context;
        this.list = list;
        options=new DisplayImageOptions.Builder()
                .cacheInMemory(true)//使用内存缓存
                .cacheOnDisk(true)//使用磁盘缓存
                .showImageOnLoading(R.mipmap.ic_launcher_round)//设置正在下载的图片
                .showImageForEmptyUri(R.mipmap.ic_launcher_round)//url为空或请求的资源不存在时
                .showImageOnFail(R.mipmap.ic_launcher_round)//下载失败时显示的图片
                .bitmapConfig(Bitmap.Config.RGB_565)//设置图片色彩模式
                .imageScaleType(ImageScaleType.EXACTLY)//设置图片的缩放模式
                .build();
    }

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

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

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        ViewHolder viewHolder;
        if (view==null)
        {
            view=View.inflate(context,R.layout.items,null);
            viewHolder=new ViewHolder();
            viewHolder.img = view.findViewById(R.id.img);
            viewHolder.txt = view.findViewById(R.id.txt);
            view.setTag(viewHolder);
        }else {
            viewHolder=(ViewHolder)view.getTag();
        }

        ImageLoader.getInstance().displayImage(list.get(i).getPicUrl(),viewHolder.img,options);
        viewHolder.txt.setText(list.get(i).getTitle());

        return view;
    }

    class ViewHolder{
        ImageView img;
        TextView txt;
    }
}

MyApplication.java

package com.example.mi;

import android.app.Application;
import android.os.Environment;

import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import java.io.File;

/**
 * Created by Administrator on 2018/3/31.
 */

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        //程序的入口 函数

        //自定义缓存路径  sd卡下的piccache文件夹下
        File cachefile=new File(Environment.getExternalStorageDirectory().getPath()+"/piccache");
        //File cachefile1=getExternalCacheDir();//获取系统默认的sd卡缓存路径

        ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(this)
                .memoryCacheExtraOptions(480, 800)//缓存图片最大的长和宽
                .threadPoolSize(2)//线程池的数量
                .threadPriority(4)
                .memoryCacheSize(2*1024*1024)//设置内存缓存区大小
                .diskCacheSize(20*1024*1024)//设置sd卡缓存区大小
                .diskCache(new UnlimitedDiscCache(cachefile))//自定义缓存目录
                .writeDebugLogs()//打印日志内容
                .diskCacheFileNameGenerator(new Md5FileNameGenerator())//给缓存的文件名进行md5加密处理
                .build();

        ImageLoader.getInstance().init(configuration);


    }
}

package com.example.mi;

import android.app.Application;
import android.os.Environment;

import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;

import java.io.File;

/**
 * Created by Administrator on 2018/3/31.
 */

public class MyApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        //程序的入口 函数

        //自定义缓存路径  sd卡下的piccache文件夹下
        File cachefile=new File(Environment.getExternalStorageDirectory().getPath()+"/piccache");
        //File cachefile1=getExternalCacheDir();//获取系统默认的sd卡缓存路径

        ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(this)
                .memoryCacheExtraOptions(480, 800)//缓存图片最大的长和宽
                .threadPoolSize(2)//线程池的数量
                .threadPriority(4)
                .memoryCacheSize(2*1024*1024)//设置内存缓存区大小
                .diskCacheSize(20*1024*1024)//设置sd卡缓存区大小
                .diskCache(new UnlimitedDiscCache(cachefile))//自定义缓存目录
                .writeDebugLogs()//打印日志内容
                .diskCacheFileNameGenerator(new Md5FileNameGenerator())//给缓存的文件名进行md5加密处理
                .build();

        ImageLoader.getInstance().init(configuration);


    }
}

DataBean.java

package com.example.mi.bean;

import java.util.List;

/**
 * Created by Administrator on 2018/3/31.
 */

public class DateBean {

    /**
     * code : 200
     * msg : success
     * newslist : [{"ctime":"2018-03-30","title":"关于红楼梦的N个念头","description":"三联生活周刊","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900671.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MTc5MTU3NTYyMQ==&idx=2&mid=2650651785&sn=75526e17b4b480ea510f65ec3793bf54"},{"ctime":"2018-03-30","title":"广州有座\u201c猪宾馆\u201d，里面的猪会\u201c尬舞\u201d？这是世界首例！","description":"广州日报","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-45262906.static/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5MjA0MDk2MA==&idx=2&mid=2652421905&sn=0ae22141145b30c848ecf0a0ac612153"},{"ctime":"2018-03-30","title":"\u201c你不就是个服务员吗？凭什么不让我换头等舱？\u201d","description":"暴走大事件","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900613.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzI4ODA1MDA2MQ==&idx=1&mid=2652647217&sn=efaa395be06b18c55b3e48a03c4a8677"},{"ctime":"2018-03-30","title":"左眼跳财，右眼跳灾？女子左眼皮连跳8年，终于出事了...","description":"FM93交通之声","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900601.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MTIzNDg3NzY2MA==&idx=3&mid=2653040765&sn=cafb01cf0ebcbd673ee4c4637764f0f2"},{"ctime":"2018-03-30","title":"千万别着急！又一大波重磅新车将上市，买早了吃亏！","description":"有车以后","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900573.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzAxMTA0ODE3Mw==&idx=1&mid=2656904565&sn=5a75df7049ca08181ecaf18476e1f370"},{"ctime":"2018-03-30","title":"2.0T+9AT的大7座SUV，卖多少钱能让你放弃汉兰达/奥迪Q5？","description":"车买买","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62898269.static/640","url":"https://mp.weixin.qq.com/s?__biz=MzA5NTU1MjEwNA==&idx=4&mid=2668673664&sn=197feccde9aad5f1c47772235c541e3e"},{"ctime":"2018-03-30","title":"黑人的头发养活了中国的一座城，这里藏着一段屈辱的民族史","description":"微在Wezeit","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900480.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzA5MjMzNTQyNw==&idx=1&mid=2656030884&sn=9a79b276f2c66c9b2694427d19ee5c72"},{"ctime":"2018-03-30","title":"朋友养了一只猛犬，网友本来是不相信的，直到靠近狗窝后.....","description":"大爱萌狗控","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900520.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5NjQ0MDE1OQ==&idx=2&mid=2650063440&sn=42593507b8b2f992795fb8ed6c675a5a"},{"ctime":"2018-03-30","title":"中国最美的20个旅行目的地，走过10个以上，就算超级旅行达人。","description":"带着相机去旅行","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900363.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzAxNjI1MzUwOA==&idx=3&mid=2247521649&sn=9c9c6d637348d975baa2c4352039f286"},{"ctime":"2018-03-30","title":"【入流】网红食物打造指南","description":"腾讯时尚","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-61887411.static/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5MTIxOTEyMA==&idx=2&mid=2650591720&sn=e7e246e4bdf3c2659fd26f36b88697fa"}]
     */

    private int code;
    private String msg;
    private List <NewslistBean> newslist;

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public List <NewslistBean> getNewslist() {
        return newslist;
    }

    public void setNewslist(List <NewslistBean> newslist) {
        this.newslist = newslist;
    }

    public static class NewslistBean {
        /**
         * ctime : 2018-03-30
         * title : 关于红楼梦的N个念头
         * description : 三联生活周刊
         * picUrl : https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900671.jpg/640
         * url : https://mp.weixin.qq.com/s?__biz=MTc5MTU3NTYyMQ==&idx=2&mid=2650651785&sn=75526e17b4b480ea510f65ec3793bf54
         */

        private String ctime;
        private String title;
        private String description;
        private String picUrl;
        private String url;

        public String getCtime() {
            return ctime;
        }

        public void setCtime(String ctime) {
            this.ctime = ctime;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        public String getDescription() {
            return description;
        }

        public void setDescription(String description) {
            this.description = description;
        }

        public String getPicUrl() {
            return picUrl;
        }

        public void setPicUrl(String picUrl) {
            this.picUrl = picUrl;
        }

        public String getUrl() {
            return url;
        }

        public void setUrl(String url) {
            this.url = url;
        }
    }
}

package com.example.mi.bean;

import java.util.List;

/**
 * Created by Administrator on 2018/3/31.
 */

public class DateBean {

    /**
     * code : 200
     * msg : success
     * newslist : [{"ctime":"2018-03-30","title":"关于红楼梦的N个念头","description":"三联生活周刊","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900671.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MTc5MTU3NTYyMQ==&idx=2&mid=2650651785&sn=75526e17b4b480ea510f65ec3793bf54"},{"ctime":"2018-03-30","title":"广州有座\u201c猪宾馆\u201d，里面的猪会\u201c尬舞\u201d？这是世界首例！","description":"广州日报","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-45262906.static/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5MjA0MDk2MA==&idx=2&mid=2652421905&sn=0ae22141145b30c848ecf0a0ac612153"},{"ctime":"2018-03-30","title":"\u201c你不就是个服务员吗？凭什么不让我换头等舱？\u201d","description":"暴走大事件","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900613.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzI4ODA1MDA2MQ==&idx=1&mid=2652647217&sn=efaa395be06b18c55b3e48a03c4a8677"},{"ctime":"2018-03-30","title":"左眼跳财，右眼跳灾？女子左眼皮连跳8年，终于出事了...","description":"FM93交通之声","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900601.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MTIzNDg3NzY2MA==&idx=3&mid=2653040765&sn=cafb01cf0ebcbd673ee4c4637764f0f2"},{"ctime":"2018-03-30","title":"千万别着急！又一大波重磅新车将上市，买早了吃亏！","description":"有车以后","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900573.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzAxMTA0ODE3Mw==&idx=1&mid=2656904565&sn=5a75df7049ca08181ecaf18476e1f370"},{"ctime":"2018-03-30","title":"2.0T+9AT的大7座SUV，卖多少钱能让你放弃汉兰达/奥迪Q5？","description":"车买买","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62898269.static/640","url":"https://mp.weixin.qq.com/s?__biz=MzA5NTU1MjEwNA==&idx=4&mid=2668673664&sn=197feccde9aad5f1c47772235c541e3e"},{"ctime":"2018-03-30","title":"黑人的头发养活了中国的一座城，这里藏着一段屈辱的民族史","description":"微在Wezeit","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900480.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzA5MjMzNTQyNw==&idx=1&mid=2656030884&sn=9a79b276f2c66c9b2694427d19ee5c72"},{"ctime":"2018-03-30","title":"朋友养了一只猛犬，网友本来是不相信的，直到靠近狗窝后.....","description":"大爱萌狗控","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900520.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5NjQ0MDE1OQ==&idx=2&mid=2650063440&sn=42593507b8b2f992795fb8ed6c675a5a"},{"ctime":"2018-03-30","title":"中国最美的20个旅行目的地，走过10个以上，就算超级旅行达人。","description":"带着相机去旅行","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900363.jpg/640","url":"https://mp.weixin.qq.com/s?__biz=MzAxNjI1MzUwOA==&idx=3&mid=2247521649&sn=9c9c6d637348d975baa2c4352039f286"},{"ctime":"2018-03-30","title":"【入流】网红食物打造指南","description":"腾讯时尚","picUrl":"https://zxpic.gtimg.com/infonew/0/wechat_pics_-61887411.static/640","url":"https://mp.weixin.qq.com/s?__biz=MjM5MTIxOTEyMA==&idx=2&mid=2650591720&sn=e7e246e4bdf3c2659fd26f36b88697fa"}]
     */

    private int code;
    private String msg;
    private List <NewslistBean> newslist;

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public List <NewslistBean> getNewslist() {
        return newslist;
    }

    public void setNewslist(List <NewslistBean> newslist) {
        this.newslist = newslist;
    }

    public static class NewslistBean {
        /**
         * ctime : 2018-03-30
         * title : 关于红楼梦的N个念头
         * description : 三联生活周刊
         * picUrl : https://zxpic.gtimg.com/infonew/0/wechat_pics_-62900671.jpg/640
         * url : https://mp.weixin.qq.com/s?__biz=MTc5MTU3NTYyMQ==&idx=2&mid=2650651785&sn=75526e17b4b480ea510f65ec3793bf54
         */

        private String ctime;
        private String title;
        private String description;
        private String picUrl;
        private String url;

        public String getCtime() {
            return ctime;
        }

        public void setCtime(String ctime) {
            this.ctime = ctime;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        public String getDescription() {
            return description;
        }

        public void setDescription(String description) {
            this.description = description;
        }

        public String getPicUrl() {
            return picUrl;
        }

        public void setPicUrl(String picUrl) {
            this.picUrl = picUrl;
        }

        public String getUrl() {
            return url;
        }

        public void setUrl(String url) {
            this.url = url;
        }
    }
}

MyDatabaseHelper.java

package com.example.mi.dateBase;

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

/**
 * Created by Administrator on 2018/4/1.
 */

public class MyDatebaseHelper extends SQLiteOpenHelper {

    //构造方法,用于确定数据库的名称,版本号等
    public MyDatebaseHelper(Context context) {
        super(context, "mydb",null,1);
    }

    //创建数据库时调用一次,初始化表中数据
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL("create table users(id integer primary key autoincrement,urlPath text,jsonData text)");
    }

    //数据库版本更新时回调
    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }
}

package com.example.mi.dateBase;

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

/**
 * Created by Administrator on 2018/4/1.
 */

public class MyDatebaseHelper extends SQLiteOpenHelper {

    //构造方法,用于确定数据库的名称,版本号等
    public MyDatebaseHelper(Context context) {
        super(context, "mydb",null,1);
    }

    //创建数据库时调用一次,初始化表中数据
    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        sqLiteDatabase.execSQL("create table users(id integer primary key autoincrement,urlPath text,jsonData text)");
    }

    //数据库版本更新时回调
    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {

    }
}

JsonDao.java

package com.example.mi.utils;

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

import com.example.mi.dateBase.MyDatebaseHelper;

/**
 * Created by Administrator on 2018/4/2.
 */

public class JsonDao {

    private final MyDatebaseHelper myDatebaseHelper;

    //构造方法,便于别类中调用
    public JsonDao(Context context){
        myDatebaseHelper = new MyDatebaseHelper(context);
    }

    //插入方法
    public void insertData(String urlpath,String jsondata){
        //1.得到数据库的可写权限
        SQLiteDatabase writableDatabase =myDatebaseHelper.getWritableDatabase();
        //2.先清空表数据
        writableDatabase.delete("users","urlPath=?",new String[]{urlpath});

        //3.新建数据对象,作为插入语句参数
        ContentValues contentValues = new ContentValues();
        //4.将要插入的数据存到对象中
        contentValues.put("urlPath",urlpath);
        contentValues.put("jsonData",jsondata);

        //5.插入数据,
        long users = writableDatabase.insert("users", null, contentValues);
    }

    public String select(String urlpath){
        //1.得到数据库的可写权限
        SQLiteDatabase writableDatabase =myDatebaseHelper.getWritableDatabase();
        //2.按条件查询
        Cursor userss = writableDatabase.query("users", null, "urlPath=?", new String[]{urlpath}, null, null, null);
        //4.创建一个字符串变量,用来储存结果
        String data="";
        //3.获得数据结果
        while (userss.moveToNext()){
            data=userss.getString(userss.getColumnIndex("jsonData"));
        }
        //返回结果
        return data;
    }

}

package com.example.mi.utils;

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

import com.example.mi.dateBase.MyDatebaseHelper;

/**
 * Created by Administrator on 2018/4/2.
 */

public class JsonDao {

    private final MyDatebaseHelper myDatebaseHelper;

    //构造方法,便于别类中调用
    public JsonDao(Context context){
        myDatebaseHelper = new MyDatebaseHelper(context);
    }

    //插入方法
    public void insertData(String urlpath,String jsondata){
        //1.得到数据库的可写权限
        SQLiteDatabase writableDatabase =myDatebaseHelper.getWritableDatabase();
        //2.先清空表数据
        writableDatabase.delete("users","urlPath=?",new String[]{urlpath});

        //3.新建数据对象,作为插入语句参数
        ContentValues contentValues = new ContentValues();
        //4.将要插入的数据存到对象中
        contentValues.put("urlPath",urlpath);
        contentValues.put("jsonData",jsondata);

        //5.插入数据,
        long users = writableDatabase.insert("users", null, contentValues);
    }

    public String select(String urlpath){
        //1.得到数据库的可写权限
        SQLiteDatabase writableDatabase =myDatebaseHelper.getWritableDatabase();
        //2.按条件查询
        Cursor userss = writableDatabase.query("users", null, "urlPath=?", new String[]{urlpath}, null, null, null);
        //4.创建一个字符串变量,用来储存结果
        String data="";
        //3.获得数据结果
        while (userss.moveToNext()){
            data=userss.getString(userss.getColumnIndex("jsonData"));
        }
        //返回结果
        return data;
    }

}

NetStateUtil.java

package com.example.mi.utils;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import com.example.mi.R;

/**
 * Created by Administrator on 2018/4/2.
 */

public class NetStateUtil {

    //判断网络是否打开
    public static boolean isConn(Context context){
        //1.设置网络状态变量,默认false(false:关闭,true:打开)
        boolean isConnFlag=false;
        //2.获得系统权限
        ConnectivityManager conManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        //3.获得网络管理权限
        NetworkInfo network = conManager.getActiveNetworkInfo();
        //4.判断是否获得权限
        if(network!=null){
            //5.获得网络连接状态
            isConnFlag=network.isAvailable();
        }
        //返回链接状态结果
        return isConnFlag;
    }

    //当没有网络时选择是否打开网络设置
    public static void showNoNetWorkDlg(final Context context){
        //1.创建弹出式对话框对象
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.mipmap.ic_launcher)//设置提示图片
                .setTitle(R.string.app_name)//设置提示标题(通常是应用名)
                .setMessage("当前没有网络连接!")//设置提示信息
                .setPositiveButton("设置", new DialogInterface.OnClickListener() {//设置确定按钮样式
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        // 跳转到系统的网络设置界面
                        Intent intent = null;
                        // 先判断当前系统版本
                        if(android.os.Build.VERSION.SDK_INT > 10){  // 3.0以上
                            intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                        }else{
                            intent = new Intent();
                            intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");
                        }
                        //开启设置页面
                        context.startActivity(intent);
                    }
                })
                .setNegativeButton("知道了", null)//设置取消按钮样式
                .show();
    }
}

package com.example.mi.utils;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;

import com.example.mi.R;

/**
 * Created by Administrator on 2018/4/2.
 */

public class NetStateUtil {

    //判断网络是否打开
    public static boolean isConn(Context context){
        //1.设置网络状态变量,默认false(false:关闭,true:打开)
        boolean isConnFlag=false;
        //2.获得系统权限
        ConnectivityManager conManager = (ConnectivityManager)context.getSystemService(Context.CONNECTIVITY_SERVICE);
        //3.获得网络管理权限
        NetworkInfo network = conManager.getActiveNetworkInfo();
        //4.判断是否获得权限
        if(network!=null){
            //5.获得网络连接状态
            isConnFlag=network.isAvailable();
        }
        //返回链接状态结果
        return isConnFlag;
    }

    //当没有网络时选择是否打开网络设置
    public static void showNoNetWorkDlg(final Context context){
        //1.创建弹出式对话框对象
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setIcon(R.mipmap.ic_launcher)//设置提示图片
                .setTitle(R.string.app_name)//设置提示标题(通常是应用名)
                .setMessage("当前没有网络连接!")//设置提示信息
                .setPositiveButton("设置", new DialogInterface.OnClickListener() {//设置确定按钮样式
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        // 跳转到系统的网络设置界面
                        Intent intent = null;
                        // 先判断当前系统版本
                        if(android.os.Build.VERSION.SDK_INT > 10){  // 3.0以上
                            intent = new Intent(android.provider.Settings.ACTION_WIRELESS_SETTINGS);
                        }else{
                            intent = new Intent();
                            intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");
                        }
                        //开启设置页面
                        context.startActivity(intent);
                    }
                })
                .setNegativeButton("知道了", null)//设置取消按钮样式
                .show();
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.mi">

    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET"/>
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        android:name=".MyApplication">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>