package com.example.news;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UnsupportedEncodingException;

import java.net.MalformedURLException;

import java.util.ArrayList;

import java.util.List;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import android.app.Activity;

import android.os.AsyncTask;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.ListView;

public class MainActivity extends Activity {

private ListView listView;

private static String URL="http://www.imooc.com/api/teacher?type=4&num=30";

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        listView=(ListView) findViewById(R.id.lv_main);

        new NewsAsyncTask().execute(URL);

    }

    //将URL对应的JSON格式数据转化为我么所封装的NewsBean

    private List<NewsBean> getJsonData(String url) {

// TODO Auto-generated method stub

    List<NewsBean> newsBeanList=new ArrayList<NewsBean>();

    try {

String jsonString=readStream(new java.net.URL(url).openStream());

JSONObject jsonObject;

NewsBean newsBean;

try {

jsonObject = new JSONObject(jsonString);

JSONArray jsonArray = jsonObject.getJSONArray("data");

for(int i=0;i<jsonArray.length();i++)

{

jsonObject = jsonArray.getJSONObject(i);

newsBean =new NewsBean();

newsBean.newsIconUrl = jsonObject.getString("picSmall");

newsBean.newsTitle = jsonObject.getString("name");

newsBean.newsContent = jsonObject.getString("description");

newsBeanList.add(newsBean);

}

} catch (JSONException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (MalformedURLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

    return newsBeanList;

}

    //通过is解析网页返回的数据

    private String readStream(InputStream is)

    {

    InputStreamReader isr;

    String result="";

    try {

    String line;

isr=new InputStreamReader(is,"utf-8");

BufferedReader br=new BufferedReader(isr);

while((line=br.readLine())!=null)

{

result+=line;

}

} catch (UnsupportedEncodingException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return result;

    }

    //实现网络的异步访问

    class NewsAsyncTask extends AsyncTask<String,Void,List<NewsBean>>

    {

@Override

protected List<NewsBean> doInBackground(String... params) {

// TODO Auto-generated method stub

return getJsonData(params[0]);

}

@Override

protected void onPostExecute(List<NewsBean> result) {

// TODO Auto-generated method stub

super.onPostExecute(result);

NewsAdapter adapter = new NewsAdapter(MainActivity.this,result);

listView.setAdapter(adapter);

}

    }

}