pulltorefresh刷新

一、主页面

package com.example.pulltorefresh;import android.os.AsyncTask;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ListView;import com.example.pulltorefresh.Adapter.NewsAdapter;
import com.example.pulltorefresh.HttpUtils.Httputils;
import com.example.pulltorefresh.HttpUtils.Networkutils;
import com.example.pulltorefresh.bean.News;
import com.example.pulltorefresh.db.NewsDao;
import com.google.gson.Gson;
import com.handmark.pulltorefresh.library.PullToRefreshBase;
import com.handmark.pulltorefresh.library.PullToRefreshListView;import java.io.IOException;import java.util.ArrayList;
import java.util.List;public class MainActivity extends AppCompatActivity {private int page = 1;private static final String TAG = "MainActivity";private PullToRefreshListView plvData;private List<News.DataBean> list;private NewsAdapter newsAdapter;private Handler handler = new Handler();private boolean isLoadMore = false;private NewsDao dao;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);plvData = findViewById(R.id.plv_data);list = new ArrayList<>();dao = new NewsDao(this);plvData.setMode(PullToRefreshBase.Mode.BOTH);plvData.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {@Overridepublic void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) {isLoadMore = false;page = 1;getData(page);handler.postDelayed(new Runnable() {@Overridepublic void run() {plvData.onRefreshComplete();}},2000);}@Overridepublic void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) {isLoadMore =true;page++;getData(page);handler.postDelayed(new Runnable() {@Overridepublic void run() {plvData.onRefreshComplete();}},2000);}});newsAdapter = new NewsAdapter(this,list);plvData.setAdapter(newsAdapter);getDataFromDB();getData(page);}private void getDataFromDB(){List<News.DataBean> dataBeans = dao.queryAll();list.clear();list.addAll(dataBeans);newsAdapter.notifyDataSetChanged();}private void getData(int page) {if (!Networkutils.isNetworkAvailable(this)){return ;}new AsyncTask<String, Integer, String>() {@Overrideprotected String doInBackground(String... strings) {String result = null;try {result = Httputils.getStringFrom(strings[0]);} catch (IOException e) {e.printStackTrace();}return result;}@Overrideprotected void onPostExecute(String s) {super.onPostExecute(s);Gson gson = new Gson();News news = gson.fromJson(s, News.class);Log.i(TAG, "onPostExecute:大牙111111111111111111111111"+news);if (news!=null){List<News.DataBean> data = news.getData();if (data!=null){int i = dao.insert(data);if (i>0){Log.i(TAG, "插入" + i + "条数据");}else{Log.i(TAG, "没有插入数据: ");}if (!isLoadMore){list.clear();;}list.addAll(data);newsAdapter.notifyDataSetChanged();}}}}.execute("http://www.xieast.com/api/news/news.php?page="+ page);}
}

二、DAO层

package com.example.pulltorefresh.db;import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.text.TextUtils;import com.example.pulltorefresh.bean.News;import java.util.ArrayList;
import java.util.List;/*** Created by 红鼻子小黑 on 2018/9/13.*/public class NewsDao {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_UTL = "url";public static final String COLUMN_THUMBNAIL01 = "thumbnail_01";public static final String COLUMN_THUMBNAIL02 = "thumbnail_02";public static final String COLUMN_THUMBNAIL03 = "thumbnail_03";private final SQLiteDatabase db;public NewsDao(Context context) {DBHelper helper = new DBHelper(context);db = helper.getWritableDatabase();}public int insert(List<News.DataBean> news) {int length = 0;ContentValues values = new ContentValues();for (News.DataBean dataBean : news) {if (!hasId(dataBean.getUniquekey())){values.put(COLUMN_ID,dataBean.getUniquekey());values.put(COLUMN_TITLE,dataBean.getTitle());values.put(COLUMN_DATE,dataBean.getDate());values.put(COLUMN_CATEGORY,dataBean.getCategory());values.put(COLUMN_AUTHOR_NAME,dataBean.getAuthor_name());values.put(COLUMN_UTL,dataBean.getUrl());values.put(COLUMN_THUMBNAIL01,TextUtils.isEmpty(dataBean.getThumbnail_pic_s())?"":dataBean.getThumbnail_pic_s());values.put(COLUMN_THUMBNAIL02,TextUtils.isEmpty(dataBean.getThumbnail_pic_s02())?"":dataBean.getThumbnail_pic_s02());values.put(COLUMN_THUMBNAIL03,TextUtils.isEmpty(dataBean.getThumbnail_pic_s03())?"":dataBean.getThumbnail_pic_s03());long l = db.insert(TABLE_NAME, null, values);if (l>0){length++;}}}return length;}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;}public List<News.DataBean> queryAll(){List<News.DataBean> news = new ArrayList<>();Cursor cursor = db.query(TABLE_NAME, null, null, null, null, null, null);while(cursor.moveToNext()){News.DataBean dataBean = new News.DataBean();dataBean.setUniquekey(cursor.getString(cursor.getColumnIndex(COLUMN_ID)));dataBean.setTitle(cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)));dataBean.setDate(cursor.getString(cursor.getColumnIndex(COLUMN_DATE)));dataBean.setCategory(cursor.getString(cursor.getColumnIndex(COLUMN_CATEGORY)));dataBean.setAuthor_name(cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR_NAME)));dataBean.setUrl(cursor.getString(cursor.getColumnIndex(COLUMN_UTL)));String Thumbnail01 = cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL01));String Thumbnail02 = cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL02));String Thumbnail03 = cursor.getString(cursor.getColumnIndex(COLUMN_THUMBNAIL03));dataBean.setThumbnail_pic_s(TextUtils.isEmpty(Thumbnail01) ? "" : Thumbnail01);dataBean.setThumbnail_pic_s02(TextUtils.isEmpty(Thumbnail02) ? "" : Thumbnail02);dataBean.setThumbnail_pic_s03(TextUtils.isEmpty(Thumbnail03) ? "" : Thumbnail03);news.add(dataBean);}return news;}
}

三、创建表Helper类

package com.example.pulltorefresh.db;import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;/*** Created by 红鼻子小黑 on 2018/9/13.*/public class DBHelper extends SQLiteOpenHelper {private static final String DB_NAME = "news.db";private static final int DB_VERSION = 1;public DBHelper(Context context) {super(context, DB_NAME, null, DB_VERSION);}@Overridepublic 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_UTL + " text," +NewsDao.COLUMN_THUMBNAIL01 + " text," +NewsDao.COLUMN_THUMBNAIL02 + " text," +NewsDao.COLUMN_THUMBNAIL03 + " text)";db.execSQL(sql);}@Overridepublic void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {}
}

四、Adapter

package com.example.pulltorefresh.Adapter;import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;import com.example.pulltorefresh.R;
import com.example.pulltorefresh.bean.News;
import com.nostra13.universalimageloader.core.ImageLoader;import java.util.List;/*** Created by 红鼻子小黑 on 2018/9/13.*/public class NewsAdapter extends BaseAdapter{private Context context;private List<News.DataBean> list;public NewsAdapter(Context context, List<News.DataBean> list) {this.context = context;this.list = list;}@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int i) {return list.get(i);}@Overridepublic long getItemId(int i) {return i;}@Overridepublic View getView(int i, View view, ViewGroup viewGroup) {ViewHolder holder = null;if (view ==null){holder = new ViewHolder();view = View.inflate(context, R.layout.item_news,null);holder.imgLogo = view.findViewById(R.id.img_logo);holder.txtTitle = view.findViewById(R.id.txt_title);holder.txtTime = view.findViewById(R.id.txt_time);view.setTag(holder);}else{holder =(ViewHolder) view.getTag();}ImageLoader.getInstance().displayImage(list.get(i).getThumbnail_pic_s(),holder.imgLogo);holder.txtTitle.setText(list.get(i).getTitle());holder.txtTime.setText(list.get(i).getDate());return view;}class ViewHolder{ImageView imgLogo;TextView txtTitle;TextView txtTime;}
}

五、图片加载缓存

package com.example.pulltorefresh;import android.app.Application;
import android.graphics.Bitmap;
import android.os.Environment;import com.nostra13.universalimageloader.cache.disc.DiskCache;
import com.nostra13.universalimageloader.cache.disc.impl.ext.LruDiskCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.cache.memory.impl.LruMemoryCache;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.display.BitmapDisplayer;
import com.nostra13.universalimageloader.core.display.CircleBitmapDisplayer;import java.io.File;
import java.io.IOException;/*** Created by 红鼻子小黑 on 2018/9/13.*/public class BaseApption extends Application{@Overridepublic void onCreate() {super.onCreate();File cacheDir = null;if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){File rootSD = Environment.getExternalStorageDirectory();cacheDir = new File(rootSD,"imgs");if (!cacheDir.exists()){cacheDir.mkdirs();}DiskCache diskCache = null;try {diskCache = new LruDiskCache(cacheDir,new  Md5FileNameGenerator(),50*1024*1024);} catch (IOException e) {e.printStackTrace();}BitmapDisplayer displayer = new CircleBitmapDisplayer();DisplayImageOptions options = new DisplayImageOptions.Builder().bitmapConfig(Bitmap.Config.RGB_565).cacheOnDisk(true).cacheInMemory(true).displayer(displayer).build();ImageLoaderConfiguration configuration = new ImageLoaderConfiguration.Builder(this).diskCache(diskCache).memoryCache(new LruMemoryCache(12*1024*1024)).defaultDisplayImageOptions(options).build();ImageLoader.getInstance().init(configuration);}}
}

五、判断有网没网

package com.example.pulltorefresh.HttpUtils;import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;/*** Created by 红鼻子小黑 on 2018/9/13.*/public class Networkutils {public static boolean isNetworkAvailable(Context context){boolean available = false;ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo networkInfo = manager.getActiveNetworkInfo();if (networkInfo!=null){available = networkInfo.isAvailable();}return available;}
}

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