Android 实时加载网络新闻

本是古典何须时尚 2022-09-25 08:29 190阅读 0赞

**实现效果：在Spinner中加载一个下拉列表，显示出所有类型新闻。**

**点击每一种类型的新闻，在布局的TestView中显示出具体内容。**

**首先写两个实体类，分别是从网络获取新闻的实体类和获取新闻接口的实体类。然后在activity中调用。**

**1.HttpUtil代码**

package com.example.administrator.jreduch09.Class;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    
    public class HttpUtil {
        public static String GetHttp(String params){
            BufferedReader reader=null;
            HttpURLConnection con = null;
            InputStream is = null;
            StringBuilder sbd = new StringBuilder();
            String str="";
            try {
                URL url = new URL(params);
                con = (HttpURLConnection) url.openConnection();
                con.setRequestProperty("apikey","5b46143955a4b1ff1b470a94315625cd");
                con.setConnectTimeout(5 * 1000);
                con.setReadTimeout(5 * 1000);
                if (con.getResponseCode() == 200) {
                    is = con.getInputStream();
                    reader=new BufferedReader(new InputStreamReader(is,"UTF-8"));
                    while ((str=reader.readLine())!=null){
                        sbd.append(str);
                        sbd.append("\r\n");
                    }
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (con != null) {
                    con.disconnect();
                }
            }
            return sbd.toString();
        }
    }

**2.UrlUtil代码：**

package com.example.administrator.jreduch09.Class;
    
    public class UrlUtil {
    
        //获取 频道的网络接口
        public  static String channelUrl = "http://apis.baidu.com/showapi_open_bus/channel_news/channel_news";
        /*获取 频道对应新闻的网络接口
          get 请求参数：
           channelId    : 新闻频道id，必须精确匹配
           channelName  :新闻频道名称，可模糊匹配
           title        :新闻标题，模糊匹配
           page         :页数，默认1。每页最多20条记
           needContent  : 是否需要返回正文，1为需要
           needHtml     :是否需要返回正文的html格式，1为需要
         */
        public  static String newsUrl = "http://apis.baidu.com/showapi_open_bus/channel_news/search_news";
    
    }

**主布局：**

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout 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.administrator.jreduch09.HttpJsonActivity">
           <Spinner
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:id="@+id/channel">
           </Spinner>
           <ScrollView
             android:layout_width="match_parent"
             android:layout_height="match_parent"
              android:layout_below="@+id/channel">
             <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/show"/>
           </ScrollView>
    </RelativeLayout>

**代码：**

package com.example.administrator.jreduch09;
    
    import android.os.AsyncTask;
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.SimpleAdapter;
    import android.widget.Spinner;
    import android.widget.TextView;
    import android.widget.Toast;
    import com.example.administrator.jreduch09.Class.HttpUtil;
    import com.example.administrator.jreduch09.Class.UrlUtil;
    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    public class HttpJsonActivity extends AppCompatActivity {
        private TextView show;
        private Spinner channel;
        private SimpleAdapter sa;
        private List<Map<String,String>> channelList;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_http_json);
            channel= (Spinner) findViewById(R.id.channel);
            show= (TextView) findViewById(R.id.show);
            channelList=new ArrayList<>();
            sa=new SimpleAdapter(this,channelList,android.R.layout.simple_spinner_item
            ,new String[]{"name"},new int[]{android.R.id.text1});
            channel.setAdapter(sa);
            new GetChannel().execute();
            channel.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                  Map map=channelList.get(position);
                    map.get("name");
                    String  channelName = (String) map.get("name");
                    String channelId = (String) map.get(channelName);
                    String url=UrlUtil.newsUrl+"?channelId="
                            +channelId+"&channelName="+channelName+"&needContent=1"
                            +"needHtml=1";
                    new GetNews().execute(url);
                }
                @Override
                public void onNothingSelected(AdapterView<?> parent) {
                }
            });
    
        }
        public class GetChannel extends AsyncTask<String,Void,String>{
    
            @Override
            protected String doInBackground(String... params) {
                return HttpUtil.GetHttp(UrlUtil.channelUrl);
            }
    
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                if(s.equals("")){
                    Toast.makeText(getBaseContext(),"网络加载异常",Toast.LENGTH_SHORT).show();
                    return;
                }
                try {
                    JSONObject obj=new JSONObject(s);
                    JSONObject obj1= obj.getJSONObject("showapi_res_body");
                    JSONArray ja=obj1.getJSONArray("channelList");
                    for(int i=0;i<ja.length();i++){
                        JSONObject channelObj= (JSONObject) ja.get(i);
                        String name=channelObj.getString("name");
                        String id=channelObj.getString("channelId");
                        Map map=new HashMap();
                        map.put("name",name);
                        map.put(name,id);
                        channelList.add(map);
                    }
                    sa.notifyDataSetChanged();
    
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }
        public  class GetNews extends  AsyncTask<String,Void,String>{
    
            @Override
            protected String doInBackground(String... params) {
                return HttpUtil.GetHttp(params[0]);
            }
    
            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                show.setText(s);
                if(s.equals("")){
                    show.setText("没有数据");
                    return;
                }else {
                    show.setText(s);
                }
            }
        }
    }

**完成效果：**

**![Center][]  
![Center 1][]**

[Center]: /images/20220718/e68d6c76d719452ab68e2b385f6d34e1.png
[Center 1]: /images/20220718/70212ac84af948458db64a168790bd94.png