PullToRefreshListView显示-显示圆形图片-判断网络并添加显示数据库

依赖

implementation project(':pulltorefresh_library')
implementation 'com.google.code.gson:gson:2.8.5'
implementation 'com.nostra13.universalimageloader:universal-image-loader:1.9.5'

清单文件

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />

创建基类

package com.example.week3lx;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.view.View;

/**
 * @Auther: 梁永辉
 * @Date: 2019/1/10 11:45:14
 * @Description:
 */
public abstract class BaseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(bindLayout());
        initView();
        initData();
        bindEvent();
    }

    protected abstract int bindLayout();

    protected abstract void initData();

    protected abstract void initView();

    protected abstract void bindEvent();

 

MainActivity继承基类

package com.example.week3lx;

import android.content.ContentValues;
import android.database.Cursor;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;

import com.example.week3lx.adapter.Myadapter;
import com.example.week3lx.bean.Bean;
import com.example.week3lx.http.Http;
import com.example.week3lx.sql.Dao;
import com.google.gson.Gson;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;

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

public class MainActivity extends BaseActivity{

    private PullToRefreshListView mpullToRefreshListView;
    //接口
    private String str="http://api.expoon.com/AppNews/getNewsList/type/1/p/1";
    private Dao dao;
    private ContentValues values;
    private Myadapter myadapter;
    private List<Bean.DataBean> data;
//============================================================
    @Override
    protected int bindLayout() {
        //进入xml
        return R.layout.activity_main;
    }
//============================================================
    @Override
    protected void initData() {
    mpullToRefreshListView.setScrollingWhileRefreshingEnabled(true);
    mpullToRefreshListView.setMode(PullToRefreshListView.Mode.BOTH);
        Http.HttpAsynTask(str, new Http.CallBackString() {
            @Override
            public void getData(String s) {
                //判断有没有网络
                boolean wl = Http.WL(MainActivity.this);
                if(wl){
                    //显示的方法
                    getjson(s);
                }else{
                    //如果没有网络显示数据库中的数据
                    Cursor query = dao.query("person", null, null, null, null, null, null);
                    ArrayList<Bean.DataBean> cxlist=new ArrayList<>();
                    if(query.moveToFirst()){
                        do {
                            String news_title = query.getString(query.getColumnIndex("news_title"));
                            String news_summary = query.getString(query.getColumnIndex("news_summary"));
                            String pic_url = query.getString(query.getColumnIndex("pic_url"));
                            cxlist.add(new Bean.DataBean(news_summary,news_title,pic_url));
                        }while(query.moveToNext());
                    }
                    Toast.makeText(MainActivity.this, "哎呀 没网了", Toast.LENGTH_LONG).show();
                    query.close();
                    //显示数据库用到的适配器
                    myadapter=new Myadapter(MainActivity.this,cxlist);
                    mpullToRefreshListView.setAdapter(myadapter);
                }
            }
        });
    }
    //============================================================
    @Override
    protected void initView() {
        //设置控件
        mpullToRefreshListView = findViewById(R.id.pull);
        //数据库的类
        dao = new Dao(MainActivity.this);
    }
//============================================================
    @Override
    protected void bindEvent() {
        //pullToRefreshListView的上下拉的方法
    mpullToRefreshListView.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
        @Override
        public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {
            //判断是否有网络
            if (Http.WL(MainActivity.this)){
            Http.HttpAsynTask(str, new Http.CallBackString() {
                @Override
                public void getData(String s) {
                        getjson(s);
                        //收起脚部
                        mpullToRefreshListView.onRefreshComplete();

                }
            });
            }else{
                Toast.makeText(MainActivity.this, "哎呀 没网了", Toast.LENGTH_LONG).show();
                mpullToRefreshListView.onRefreshComplete();
            }
        }
        @Override
        public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {
            //判断是否有网络
            if (Http.WL(MainActivity.this)){
            Http.HttpAsynTask(str, new Http.CallBackString() {
                @Override
                public void getData(String s) {

                        Gson gson=new Gson();
                        Bean bean = gson.fromJson(s, Bean.class);
                        List<Bean.DataBean> datas = bean.getData();
                        data.addAll(datas);
                        myadapter = new Myadapter(MainActivity.this,data);

                        mpullToRefreshListView.onRefreshComplete();
                        myadapter.notifyDataSetChanged();
                }
            });
            }else{
                Toast.makeText(MainActivity.this, "哎呀 没网了", Toast.LENGTH_LONG).show();
                mpullToRefreshListView.onRefreshComplete();
            }
        }
    });
    }
    //============================================================
    private void getjson(String s) {
        //gsoj控件
        Gson gson=new Gson();
        Bean bean = gson.fromJson(s, Bean.class);
        data = bean.getData();
        //判断数据库中是否有相同数据
        if(dao.query("person",null,null,null,null,null,null).moveToFirst()){

        }else{
            //没有相同的数据进行添加
            for(Bean.DataBean bean1 : data){
                values = new ContentValues();
                values.put("news_title",bean1.getNews_title());
                values.put("news_summary",bean1.getNews_summary());
                values.put("pic_url",bean1.getPic_url());
                dao.add("person",null,values);
            }
        }
        //适配器
        myadapter = new Myadapter(MainActivity.this, data);
        mpullToRefreshListView.setAdapter(myadapter);
    }
}

数据库（表）

package com.example.week3lx.sql;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
lic class Mysql extends SQLiteOpenHelper {
    public Mysql(Context context) {
        super(context, "bw", null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
    //数据库的表
    db.execSQL("CREATE TABLE person(id INTEGER PRIMARY KEY AUTOINCREMENT,news_title VARCHAR(20),news_summary VARCHAR(20),pic_url VARCHAR(20))");
    }

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

    }
}

数据库进行增删改查

package com.example.week3lx.sql;

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

public class Dao {

    private final SQLiteDatabase db;

    public Dao(Context context) {
        Mysql mysql=new Mysql(context);
        db = mysql.getWritableDatabase();
    }
    public  long add(String table, String nullColumnHack, ContentValues values){
        return db.insert(table,nullColumnHack,  values);
    }
    public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy){
        return db.query( table, columns,selection, selectionArgs,groupBy, having, orderBy);
    }
}

http用于显示PullToRefreshListView和判断网络

package com.example.week3lx.http;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

public class Http {
    public static void HttpAsynTask(String strUlr,final CallBackString callBackString){
        new AsyncTask<String,Integer,String>(){
            @Override
            protected String doInBackground(String... strings) {
                return HttpGet(strings[0]);
            }
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                callBackString.getData(s);
            }
        }.execute(strUlr);
    }
    public interface CallBackString{
        void getData(String s);
    }
    //请求网络
    public static boolean WL(Context context){
        if(context!=null){
            ConnectivityManager connectivityManager =(ConnectivityManager)
                    context.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo info = connectivityManager.getActiveNetworkInfo();
            if(info!=null){
                return info.isConnected();
            }
        }
        return false;
    }
    //get方法
    public static String HttpGet(String str){
        try {
            URL url = new URL(str);
            HttpURLConnection connection =(HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setReadTimeout(5000);
            connection.setConnectTimeout(5000);
            InputStream stream = connection.getInputStream();
            BufferedReader reader=new BufferedReader(new InputStreamReader(stream,"utf-8"));
            StringBuilder builder = new StringBuilder();
            String s="";
            while((s=reader.readLine())!=null){
                builder.append(s);
            }
            connection.disconnect();
            return builder.toString();
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

显示图片和显示图片形状

package com.example.week3lx.app;

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

import com.example.week3lx.R;
import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiskCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.display.CircleBitmapDisplayer;

import java.io.File;

/**
*/
public class App extends Application {
    File file=new File(Environment.getExternalStorageDirectory()+"/"+"img");
    @Override
    public void onCreate() {
        super.onCreate();
        DisplayImageOptions options=new DisplayImageOptions.Builder()
                .cacheOnDisk(true)//让图片进行sdcard缓存
                .cacheInMemory(true)//让图片进行内存缓存
                .showImageOnFail(R.mipmap.zhao)
                .displayer(new CircleBitmapDisplayer())
                .build();
        ImageLoaderConfiguration configuration=new ImageLoaderConfiguration.Builder(this)
                //设置圆形图片 注意：图片一定要有高和宽不让和显示不出来
                .defaultDisplayImageOptions(options)
                .diskCache(new UnlimitedDiskCache(file))//UnlimitedDiskCache 限制这个图片的缓存路径
                .diskCacheFileNameGenerator(new Md5FileNameGenerator())//MD5这种方式生成缓存文件的名字
                .build();
        ImageLoader imageLoader=ImageLoader.getInstance();
        imageLoader.init(configuration);
    }
}

Adapter

package com.example.week3lx.adapter;

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.example.week3lx.BaseActivity;
import com.example.week3lx.R;
import com.example.week3lx.bean.Bean;
import com.nostra13.universalimageloader.core.ImageLoader;

import java.util.List;

public class Myadapter  extends BaseAdapter {
    private Context context;
    List<Bean.DataBean> list;

    public Myadapter(Context context, List<Bean.DataBean> list) {
        this.context = context;
        this.list = list;
    }
    @Override
    public int getCount() {
        return list.size();
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {
        ViewHolder holder;
        if(view==null){
            view = LayoutInflater.from(context).inflate(R.layout.itme, null);
            holder=new ViewHolder();
            holder.name = view.findViewById(R.id.textView);
            holder.name2 = view.findViewById(R.id.textView1);
            holder.image=view.findViewById(R.id.image);
            view.setTag(holder);
        }else{
            holder = (ViewHolder) view.getTag();
        }
        holder.name.setText(list.get(i).getNews_title());
        holder.name2.setText(list.get(i).getNews_summary());
        Bean.DataBean dataBean = list.get(i);
        String url = dataBean.getPic_url();
        ImageLoader.getInstance().displayImage(url,holder.image);
        return view;
    }
    class ViewHolder{
        TextView name,name2;
        ImageView image;
    }
}

效果图