网络获取数据列表下拉刷新上拉加载更多练习
第一步首先导入PullToRefresh的包Library
布局文件：
item_layout.xml文件：
xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
android:id="@+id/food_iv"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_margin="20dp" />
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
android:id="@+id/food_name_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="20sp"
android:textSize="20sp" />
android:id="@+id/food_str_tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20sp"
android:textSize="20sp" />
main_layout.xml文件：
xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mrzhao.qbbdemo.MainActivity">
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="match_parent">
FoodEntity:
public class FoodEntity { /** * ret : 1 * data : [{"id":"8289","title":"油焖大虾","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/9/8289.jpg","collect_num":"1659","food_str":"大虾 葱 生姜 植物油 料酒","num":1659},{"id":"2127","title":"四川回锅肉","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2127.jpg","collect_num":"1585","food_str":"猪肉 青蒜 青椒 红椒 姜片","num":1585},{"id":"30630","title":"超简单芒果布丁","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/31/30630.jpg","collect_num":"1527","food_str":"QQ糖 牛奶 芒果","num":1527},{"id":"9073","title":"家常红烧鱼","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/10/9073.jpg","collect_num":"1418","food_str":"鲜鱼 姜 葱 蒜 花椒","num":1418},{"id":"10097","title":"家常煎豆腐","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10097.jpg","collect_num":"1405","food_str":"豆腐 新鲜红椒 青椒 葱花 油","num":1405},{"id":"10509","title":"水煮肉片","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10509.jpg","collect_num":"1336","food_str":"瘦猪肉 生菜 豆瓣酱 干辣椒 花椒","num":1336},{"id":"46968","title":"红糖苹果银耳汤","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/47/46968.jpg","collect_num":"1245","food_str":"银耳 苹果 红糖","num":1245},{"id":"10191","title":"麻婆豆腐","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10191.jpg","collect_num":"1214","food_str":"豆腐 肉末 生抽 白糖 芝麻油","num":1214},{"id":"2372","title":"皮蛋瘦肉粥","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2372.jpg","collect_num":"1145","food_str":"大米 皮蛋 猪肉 油条 香葱","num":1145},{"id":"2166","title":"蚂蚁上树","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2166.jpg","collect_num":"1140","food_str":"红薯粉 肉 姜 蒜 花椒","num":1140},{"id":"2262","title":"糖醋肉","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2262.jpg","collect_num":"1074","food_str":"猪肉 红椒 黄椒 洋葱 蛋清","num":1074},{"id":"9971","title":"鱼香豆腐","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/10/9971.jpg","collect_num":"1003","food_str":"豆腐 木耳 胡萝卜 香葱 番茄酱","num":1003},{"id":"10172","title":"干煸四季豆","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10172.jpg","collect_num":"988","food_str":"四季豆 干辣椒 蒜头 酱油 糖","num":988},{"id":"2685","title":"胡萝卜肉末蒸蛋","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2685.jpg","collect_num":"916","food_str":"胡萝卜 肉 蛋 生抽 盐","num":916},{"id":"9972","title":"虎皮青椒","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/10/9972.jpg","collect_num":"889","food_str":"青辣椒 大蒜 香醋 白糖 生抽","num":889},{"id":"10437","title":"叉烧排骨","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10437.jpg","collect_num":"797","food_str":"排骨 李锦记叉烧酱 植物油 清水 油菜","num":797},{"id":"2892","title":"\u201c五行\u201d彩蔬汤","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2892.jpg","collect_num":"756","food_str":"黑木耳 玉米 牛蒡 胡萝卜 西兰花","num":756},{"id":"33783","title":"美人豆浆","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/34/33783.jpg","collect_num":"753","food_str":"黄豆 红豆 绿豆 黑豆 黑米","num":753},{"id":"2348","title":"麻辣肉丝面","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/3/2348.jpg","collect_num":"753","food_str":"面条 肉丝 淀粉 酱油 辣椒","num":753},{"id":"10044","title":"土豆炖翅根","pic":"http://www.qubaobei.com/ios/cf/uploadfile/132/11/10044.jpg","collect_num":"752","food_str":"土豆 翅根 葱 姜 料酒","num":752}] */ private int ret; private List<DataBean> data; public int getRet() { return ret; } public void setRet(int ret) { this.ret = ret; } public List<DataBean> getData() { return data; } public void setData(List<DataBean> data) { this.data = data; } public static class DataBean { /** * id : 8289 * title : 油焖大虾 * pic : http://www.qubaobei.com/ios/cf/uploadfile/132/9/8289.jpg * collect_num : 1659 * food_str : 大虾 葱 生姜 植物油 料酒 * num : 1659 */ private String id; private String title; private String pic; private String collect_num; private String food_str; private int num; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getPic() { return pic; } public void setPic(String pic) { this.pic = pic; } public String getCollect_num() { return collect_num; } public void setCollect_num(String collect_num) { this.collect_num = collect_num; } public String getFood_str() { return food_str; } public void setFood_str(String food_str) { this.food_str = food_str; } public int getNum() { return num; } public void setNum(int num) { this.num = num; } } }
适配器MyAdapter:
public class MyAdapter extends BaseAdapter { private List<FoodEntity.DataBean> list; private Context context; private LayoutInflater inflater; public MyAdapter(List<FoodEntity.DataBean> list, Context context) { this.list = list; this.context = context; //初始化布局加载器 inflater = LayoutInflater.from(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 View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = null; if (convertView == null) { convertView = inflater.inflate(R.layout.item_layout, parent, false); holder = new ViewHolder(); holder.foodPicIv = (ImageView) convertView.findViewById(R.id.food_iv); holder.foodNameTv = (TextView) convertView.findViewById(R.id.food_name_tv); holder.foodStrTv = (TextView) convertView.findViewById(R.id.food_str_tv); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } FoodEntity.DataBean dataBean = list.get(position); holder.foodNameTv.setText(dataBean.getTitle()); holder.foodStrTv.setText(dataBean.getFood_str()); //显示图片 Picasso.with(context).load(dataBean.getPic()).into(holder.foodPicIv); return convertView; } static class ViewHolder { ImageView foodPicIv; TextView foodNameTv; TextView foodStrTv; } }
MainActivity:
public class MainActivity extends AppCompatActivity { private PullToRefreshListView listView; //想要访问的网络路径 private String path = ""; //定义数据源 private List<FoodEntity.DataBean> list = new ArrayList<>(); private MyAdapter myAdapter; //定义一个页码 private int pager = 1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); listView = (PullToRefreshListView) findViewById(R.id.listView); //设置支持下拉刷新及上拉加载更多 listView.setMode(PullToRefreshBase.Mode.BOTH); //创建一个适配器 myAdapter = new MyAdapter(list, this); //设置适配器 listView.setAdapter(myAdapter); //添加条目点击事件 listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView parent, View view, int position, long id) { //点击的条目的对应数据实体 FoodEntity.DataBean dataBean = list.get(position - 1); Toast.makeText(MainActivity.this, dataBean.getTitle(), Toast.LENGTH_SHORT).show(); AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this); builder.setTitle("食物信息"); //初始化自定义的View View dialogView = LayoutInflater.from(MainActivity.this).inflate(R.layout.item_layout, null); //实例化每个字视图 ImageView foodIv = (ImageView) dialogView.findViewById(R.id.food_iv); TextView foodNameTv = (TextView) dialogView.findViewById(R.id.food_name_tv); TextView foodStrTv = (TextView) dialogView.findViewById(R.id.food_str_tv); //设置字视图应该展示的内容 Picasso.with(MainActivity.this).load(dataBean.getPic()).into(foodIv); foodNameTv.setText(dataBean.getTitle()); foodStrTv.setText(dataBean.getFood_str()); //设置视图 builder.setView(dialogView); //展示视图 builder.show(); } }); listView.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() { @Override public void onPullDownToRefresh(PullToRefreshBase<ListView> refreshView) { //下拉刷新执行 pager = 1; //清空原来的数据 list.clear(); //执行下载 new MyTask().execute(); } @Override public void onPullUpToRefresh(PullToRefreshBase<ListView> refreshView) { //上拉加载更多执行 pager++; //执行下载 new MyTask().execute(); } }); //获取路径 getPathFromAssets(); //开启下载 new MyTask().execute(); } /** * 获取网络数据的异步任务 */ class MyTask extends AsyncTask<Void, Void, String> { @Override protected String doInBackground(Void... params) { return getJSONFromNet(path + pager); } @Override protected void onPostExecute(String s) { super.onPostExecute(s); //刷新完成 listView.onRefreshComplete(); if (!TextUtils.isEmpty(s)) { Gson gson = new Gson(); FoodEntity foodEntity = gson.fromJson(s, FoodEntity.class); //获取数据中的集合 List<FoodEntity.DataBean> data = foodEntity.getData(); if (data != null && data.size() > 0) { //更新UI list.addAll(data); //数据源更新后刷新适配器 myAdapter.notifyDataSetChanged(); } } } } /** * 网络获取json数据工具类 * * @param path * @return */ public String getJSONFromNet(String path) { InputStream inputStream = null; ByteArrayOutputStream outputStream = null; try { URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(30 * 1000); conn.setReadTimeout(30 * 1000); conn.connect(); if (conn.getResponseCode() == 200) { inputStream = conn.getInputStream(); outputStream = new ByteArrayOutputStream(); int len = 0; byte[] bytes = new byte[1024]; while ((len = inputStream.read(bytes)) != -1) { outputStream.write(bytes, 0, len); } return outputStream.toString(); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (ProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { if (inputStream != null) { try { inputStream.close(); } catch (IOException e) { e.printStackTrace(); } } if (outputStream != null) { try { outputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; } /** * 从Assets里获取 想要访问的路径 */ private void getPathFromAssets() { try { //获取内容的流 InputStream inputStream = getAssets().open("path.txt"); byte[] bytes = new byte[inputStream.available()]; inputStream.read(bytes); ByteArrayOutputStream opt = new ByteArrayOutputStream(); opt.write(bytes, 0, bytes.length); //拿到最终的结果 path = opt.toString(); } catch (IOException e) { e.printStackTrace(); } } }