基类抽取http服务(网络判断)数据库多条目加载上拉加载下拉刷新

//BaseActivity
public abstract class BaseActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(initLayout());
        initview();
        getNews();
    }
    /**
     * 设置布局文件
     */
    protected abstract int initLayout();
    /**
     * 初始化控件
     */
    protected abstract void initview();
    /**
     * 获得数据
     */
    protected abstract void getNews();
}

//主页面

public class MainActivity extends BaseActivity implements View.OnClickListener {

    private DrawerLayout dra_layout;
    private Button btn_1,btn_2,btn_3;
    private ArrayList<Fragment> fragment;
    private ViewPager view_pager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //设置监听
        view_pager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
            @Override
            public Fragment getItem(int i) {
                return fragment.get(i);
            }

            @Override
            public int getCount() {
                return fragment.size();
            }
        });
        btn_1.setOnClickListener(this);
        btn_2.setOnClickListener(this);
        btn_3.setOnClickListener(this);
    }

    @Override
    protected int initLayout() {
        return R.layout.activity_main;
    }

    @Override
    protected void initview() {
         //初始化控件
        dra_layout = findViewById(R.id.drawer_layout);
        view_pager = findViewById(R.id.view_pager);
        btn_1 = findViewById(R.id.btn_1);
        btn_2 = findViewById(R.id.btn_2);
        btn_3 = findViewById(R.id.btn_3);
        //创建集合
        fragment = new ArrayList<>();
        fragment.add(new OneFragment());
        fragment.add(new TwoFragment());
        fragment.add(new ThreeFragment());
    }
    @Override
    protected void getNews() {

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_1:
                view_pager.setCurrentItem(0);
                break;
            case R.id.btn_2:
                view_pager.setCurrentItem(1);
                break;
            case R.id.btn_3:
                view_pager.setCurrentItem(2);
                break;
        }
    }
}

//碎片

public abstract class BaseFragment extends Fragment {
    
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
             super.onViewCreated(view, savedInstanceState);

             initView(view);
             getDatas();
}


  abstract void initView(View view);
  abstract void getDatas();
}

public class OneFragment extends BaseFragment {
    private static final String TAG = "ConcernFragment";
    public static final String NEWS_URL="http://www.xieast.com/api/news/news.php?page=";
    private int page=1;
    private boolean isLoadMore= false;
    private XListView list_view;
    private ArrayList<News.DataBean> list;
    private MyAdapter adapter;
    private NewsDao dao;
    private static final int FLAG = 123;
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case FLAG:
                    String result = (String) msg.obj;
                    Gson gson = new Gson();
                    News news = gson.fromJson(result, News.class);
                    if (news != null) {
                        ArrayList<News.DataBean> data = (ArrayList<News.DataBean>) news.getData();
                        if (data != null) {
                            // 添加到数据库中
                            int i = dao.insert(data);
                            if (i > 0) {
                                Log.i(TAG, "插入了: " + i + "条数据");
                            }
                            if (!isLoadMore) {
                                list.clear();
                            }
                            list.addAll(data);
                            adapter.notifyDataSetChanged();
                        }
                    }

                    postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            list_view.stopRefresh();
                        }
                    }, 2000);

                    break;
            }
        }
    };
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
       View view= inflater.inflate(R.layout.fragment_one, container, false);
        return view;
    }

    @Override
    void initView(View view) {
         //初始化控件
         list_view=view.findViewById(R.id.list_view);
         //创建集合
         list=new ArrayList<>();
         //创建适配器
         adapter=new MyAdapter(list,getActivity());
         list_view.setAdapter(adapter);
         dao=new NewsDao(getActivity());
        //设置上拉加载下拉刷新
        list_view.setPullLoadEnable(true);
        list_view.setPullRefreshEnable(true);
        //设置Xlistview监听事件
        list_view.setXListViewListener(new XListView.IXListViewListener() {
            @Override
            public void onRefresh() {
                if (page>1){
                    page--;
                }else {
                    Toast.makeText(getActivity(),"给不了亲更多信息了!!!",Toast.LENGTH_LONG).show();
                }
                isLoadMore=false;
                getDatas();
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        list_view.stopRefresh();
                    }
                },1000);
                long l = System.currentTimeMillis();
                Date date = new Date(l);
                SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm");
                list_view.setRefreshTime(format.format(date));
            }

            @Override
            public void onLoadMore() {
                page ++;
                isLoadMore = true;
                getDatas();
                News news = new News();
                ArrayList<News.DataBean> result = (ArrayList<News.DataBean>) news.getData();
                if (result == null){
                    Toast.makeText(getActivity(),"没有更多的数据了",Toast.LENGTH_SHORT).show();
                }
                handler.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        list_view.stopLoadMore();
                    }
                },1000);
            }
        });
    }

    @Override
    void getDatas() {
        if (NetworkConnected.isNetworkConnected(getActivity())){
            getDataFromHttp();
        }else {
            getDataFromDB();
        }
    }
    //开启线程请求数据
    private void getDataFromHttp() {
        new AsyncTask<String,Integer,String>(){
            @Override
            protected String doInBackground(String... strings) {
                String s = HttpUtils.getHttpUrlConnection(strings[0]);
                Message msg = Message.obtain();
                msg.what = FLAG;
                msg.obj = s;
                handler.sendMessage(msg);
                return s;
            }
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                Gson gson = new Gson();
                News news = gson.fromJson(s, News.class);
                if (news != null){
                    ArrayList<News.DataBean> result = (ArrayList<News.DataBean>) news.getData();
                    if (result != null){
                        if (!isLoadMore){
                            list.clear();
                        }
                        list.addAll(result);
                        adapter.notifyDataSetChanged();
                    }
                }
            }
        }.execute(NEWS_URL+page);
    }
    //从数据库获得数据
    public void getDataFromDB(){
        ArrayList<News.DataBean> dataBeans = dao.queryPage(page);
        if (dataBeans != null) {
            if (!isLoadMore) {
                list.clear();
            }
            list.addAll(dataBeans);
            adapter.notifyDataSetChanged();
        }

        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                list_view.stopRefresh();
            }
        }, 2000);
    }
}

//适配器

public class MyAdapter extends BaseAdapter {
    private static final int TYPE_ONE_PIC = 0;
    private static final int TYPE_TWO_PIC = 1;
    private static final int TYPE_THREE_PIC = 2;
    private ArrayList<News.DataBean> list;
    private Context context;

    public MyAdapter(ArrayList<News.DataBean> list, Context context) {
        this.list = list;
        this.context = context;
    }

    @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 int getViewTypeCount() {
        return 3;
    }

    @Override
    public int getItemViewType(int position) {
        News.DataBean bean = list.get(position);
        if (!TextUtils.isEmpty(bean.getThumbnail_pic_s03())) {
            return TYPE_THREE_PIC;
        } else if (!TextUtils.isEmpty(bean.getThumbnail_pic_s02())) {
            return TYPE_TWO_PIC;
        } else {
            return TYPE_ONE_PIC;
        }
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder1 holder1 = null;
        ViewHolder2 holder2 = null;
        ViewHolder3 holder3 = null;
        int type = getItemViewType(position);
        switch (type) {
            case TYPE_ONE_PIC:
                if (convertView == null) {
                    holder1 = new ViewHolder1();
                    convertView = View.inflate(context, R.layout.item_news_01, null);
                    holder1.txtTitle = convertView.findViewById(R.id.txt_title);
                    holder1.imgLogo1 = convertView.findViewById(R.id.img_logo_01);
                    convertView.setTag(holder1);
                } else {
                    holder1 = (ViewHolder1) convertView.getTag();
                }
                holder1.txtTitle.setText(list.get(position).getTitle());
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s(),
                        holder1.imgLogo1);
                break;
            case TYPE_TWO_PIC:
                if (convertView == null) {
                    holder2 = new ViewHolder2();
                    convertView = View.inflate(context, R.layout.item_news_02, null);
                    holder2.txtTitle = convertView.findViewById(R.id.txt_title);
                    holder2.imgLogo1 = convertView.findViewById(R.id.img_logo_01);
                    holder2.imgLogo2 = convertView.findViewById(R.id.img_logo_02);
                    convertView.setTag(holder2);
                } else {
                    holder2 = (ViewHolder2) convertView.getTag();
                }
                holder2.txtTitle.setText(list.get(position).getTitle());
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s(),
                        holder2.imgLogo1);
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s02(),
                        holder2.imgLogo2);
                break;
            case TYPE_THREE_PIC:
                if (convertView == null) {
                    holder3 = new ViewHolder3();
                    convertView = View.inflate(context, R.layout.item_news_03, null);
                    holder3.txtTitle = convertView.findViewById(R.id.txt_title);
                    holder3.imgLogo1 = convertView.findViewById(R.id.img_logo_01);
                    holder3.imgLogo2 = convertView.findViewById(R.id.img_logo_02);
                    holder3.imgLogo3 = convertView.findViewById(R.id.img_logo_03);
                    convertView.setTag(holder3);
                } else {
                    holder3 = (ViewHolder3) convertView.getTag();
                }
                holder3.txtTitle.setText(list.get(position).getTitle());
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s(),
                        holder3.imgLogo1);
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s02(),
                        holder3.imgLogo2);
                ImageLoader.getInstance().displayImage(list.get(position).getThumbnail_pic_s03(),
                        holder3.imgLogo3);
                break;
        }

        return convertView;
    }
    class ViewHolder1 {
        TextView txtTitle;
        ImageView imgLogo1;
    }

    class ViewHolder2 {
        TextView txtTitle;
        ImageView imgLogo1;
        ImageView imgLogo2;
    }

    class ViewHolder3 {
        TextView txtTitle;
        ImageView imgLogo1;
        ImageView imgLogo2;
        ImageView imgLogo3;
    }
}

//http工具类    网络判断

public class HttpUtils {

    public static String getHttpUrlConnection(String urlString){
        String result = "";
        try {
            URL url = new URL(urlString);
            //连接
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            //优化
            //请求类型
            connection.setRequestMethod("GET");
            connection.setDoInput(true);
            connection.setDoOutput(false);
            connection.setUseCaches(false);
            //超时时间
            connection.setConnectTimeout(3000);
            connection.connect();

            //获取状态码   200 成功
            if(connection.getResponseCode() == 200){
                InputStream is = connection.getInputStream();
                result = getInputStream(is);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

    private static String getInputStream(InputStream is) {
        String result = "";
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            int count = -1;
            byte[] buffer = new byte[1024];
            while ((count = is.read(buffer,0,buffer.length)) != -1){
                baos.write(buffer,0,count);
                baos.flush();
            }
            result = baos.toString();
            baos.close();
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }
}

public class NetworkConnected {
    //判断是否有网络
    public static boolean isNetworkConnected(Context context) {
        if (context != null) {
            ConnectivityManager mConnectivityManager = (ConnectivityManager) context
                    .getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
            if (mNetworkInfo != null) {
                return mNetworkInfo.isAvailable();
            }
        }
        return false;
    }
}

//Dao包和

public class NewsDao {
    private final SQLiteDatabase db;

    public static final String TABLE_NAME = "news";
    public static final String COLUMN_ID = "id";
    public static final String COLUMN_TITLE = "title";
    public static final String COLUMN_DATE = "_date";
    public static final String COLUMN_CATEGORY = "category";
    public static final String COLUMN_AUTHOR_NAME = "author_name";
    public static final String COLUMN_URL = "url";
    public static final String COLUMN_THUMBNAIL_01 = "thumbnail_pic_s";
    public static final String COLUMN_THUMBNAIL_02 = "thumbnail_pic_s02";
    public static final String COLUMN_THUMBNAIL_03 = "thumbnail_pic_s03";

    public NewsDao(Context context) {
        DBHelper helper = new DBHelper(context);
        db = helper.getWritableDatabase();
    }

    /**
     * 插入数据
     *
     * @param list
     * @return
     */
    public int insert(ArrayList<News.DataBean> list) {
        int count = 0;
        ContentValues values = new ContentValues();
        for (News.DataBean bean : list) {
            /**
             * 有这条数据就不作操作，没有的时候才插入
             */
            if (!hasId(bean.getUniquekey())) {
                values.put(COLUMN_ID, bean.getUniquekey());
                values.put(COLUMN_TITLE, bean.getTitle());
                values.put(COLUMN_DATE, bean.getDate());
                values.put(COLUMN_CATEGORY, bean.getCategory());
                values.put(COLUMN_AUTHOR_NAME, bean.getAuthor_name());
                values.put(COLUMN_URL, bean.getUrl());
                values.put(COLUMN_THUMBNAIL_01, TextUtils.isEmpty(bean.getThumbnail_pic_s()) ? "" : bean.getThumbnail_pic_s());
                values.put(COLUMN_THUMBNAIL_02, TextUtils.isEmpty(bean.getThumbnail_pic_s02()) ? "" : bean.getThumbnail_pic_s02());
                values.put(COLUMN_THUMBNAIL_03, TextUtils.isEmpty(bean.getThumbnail_pic_s03()) ? "" : bean.getThumbnail_pic_s03());
                long l = db.insert(TABLE_NAME, null, values);
                if (l > 0) {
                    count++;
                }
            }
        }
        return count;
    }

    /**
     * 查询数据库中有没有这条id的数据
     *
     * @param id
     * @return
     */
    public boolean hasId(String id) {
        Cursor cursor = db.query(TABLE_NAME, null, COLUMN_ID + "=?", new String[]{id}, null, null, null);
        if (cursor.moveToNext()) {
            return true;
        }
        return false;
    }

    /**
     * 查询所有的数据
     *
     * @return
     */
    public ArrayList<News.DataBean> queryAll() {
        ArrayList<News.DataBean> list = new ArrayList<>();
        Cursor cursor = db.query(TABLE_NAME, null, null, null, null, null, null);
        while (cursor.moveToNext()) {
            News.DataBean bean = new News.DataBean();
            bean.setUniquekey(cursor.getString(cursor.getColumnIndex(COLUMN_ID)));
            bean.setTitle(cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)));
            bean.setDate(cursor.getString(cursor.getColumnIndex(COLUMN_DATE)));
            bean.setAuthor_name(cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR_NAME)));
            bean.setCategory(cursor.getString(cursor.getColumnIndex(COLUMN_CATEGORY)));
            bean.setUrl(cursor.getString(cursor.getColumnIndex(COLUMN_URL)));
            bean.setThumbnail_pic_s(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_01)));
            bean.setThumbnail_pic_s02(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_02)));
            bean.setThumbnail_pic_s03(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_03)));
            list.add(bean);
        }
        return list;
    }

    /**
     * 根据页数查询出数据
     * @param page
     * @return
     */
    public ArrayList<News.DataBean> queryPage(int page) {
//        page=1 ==> 0-29,  limit 0, 30
//        page=2 ==> 30-59  limit 30, 30
        String limit = (page - 1) * 30 + ", 30";
        ArrayList<News.DataBean> list = new ArrayList<>();
        Cursor cursor = db.query(TABLE_NAME, null, null, null, null, null, null, limit);
        while (cursor.moveToNext()) {
            News.DataBean bean = new News.DataBean();
            bean.setUniquekey(cursor.getString(cursor.getColumnIndex(COLUMN_ID)));
            bean.setTitle(cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)));
            bean.setDate(cursor.getString(cursor.getColumnIndex(COLUMN_DATE)));
            bean.setAuthor_name(cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR_NAME)));
            bean.setCategory(cursor.getString(cursor.getColumnIndex(COLUMN_CATEGORY)));
            bean.setUrl(cursor.getString(cursor.getColumnIndex(COLUMN_URL)));
            bean.setThumbnail_pic_s(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_01)));
            bean.setThumbnail_pic_s02(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_02)));
            bean.setThumbnail_pic_s03(cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL_03)));
            list.add(bean);
        }
        return list;
    }
}

public class DBHelper extends SQLiteOpenHelper {
    public static final String DB_NAME = "news.db";
    public static final int DB_VERSION = 1;

    public DBHelper(Context context) {
        super(context, DB_NAME, null, DB_VERSION);
    }
    @Override
    public void onCreate(SQLiteDatabase db) {
        String sql = "create table " + NewsDao.TABLE_NAME + "(" + NewsDao.COLUMN_ID
                + " text primary key," +
                NewsDao.COLUMN_TITLE + " text," +
                NewsDao.COLUMN_DATE + " text," +
                NewsDao.COLUMN_CATEGORY + " text," +
                NewsDao.COLUMN_AUTHOR_NAME + " text," +
                NewsDao.COLUMN_URL + " text," +
                NewsDao.COLUMN_THUMBNAIL_01 + " text," +
                NewsDao.COLUMN_THUMBNAIL_02 + " text," +
                NewsDao.COLUMN_THUMBNAIL_03 + " text)";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

//ImageLoader全局配置

public class MyApplication extends Application {
    private File file;
    private DiskCache diskCache;

    @Override
    public void onCreate() {
        super.onCreate();

        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
            File rootSD = Environment.getExternalStorageDirectory();
            file = new File(rootSD, "imagefile");
            if (!file.exists()){
                file.mkdirs();
            }
        }

        try {
            diskCache = new LruDiskCache(file, new Md5FileNameGenerator(), 50 * 1024 * 1024);
        } catch (IOException e) {
            e.printStackTrace();
        }
        BitmapDisplayer displayer = new RoundedBitmapDisplayer(10);

        DisplayImageOptions options = new DisplayImageOptions.Builder()
                .cacheInMemory(true)
                .cacheOnDisk(true)
                .bitmapConfig(Bitmap.Config.RGB_565)
                .displayer(displayer)
                .showImageForEmptyUri(R.mipmap.ic_launcher)
                .showImageOnFail(R.mipmap.ic_launcher)
                .showImageOnLoading(R.mipmap.ic_launcher)
                .build();

        ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(this)
                .diskCache(diskCache)
                .memoryCache(new LruMemoryCache(12*1024*1024))
                .threadPoolSize(3)
                .defaultDisplayImageOptions(options)
                .build();

        ImageLoader.getInstance().init(configuration);
    }
}

//清单文件

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

    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"
        tools:ignore="ProtectedPermissions" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

    <application
        android:name=".MyApplication"
        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">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

</manifest>