Obtains data from the network, parses the output.

What we want to do is get the data from the network and show it in the activity.

First we will import the Gson package, which is the function of converting the JSON string into an equal Java object. The method of obtaining data from the network and saving the data is written into class, which is convenient for later invocation.

import Java.io.BufferedReader; Getting data from the network
import java.io.IOException;
import Java.io.InputStream;
import Java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import Java.net.URL;

/**
* Created by Administrator on 2016/8/17.
 */
Public class Httputil {
Public static string HttpGet (String params) {
        {
httpurlconnection Con=null; // HttpURLConnection How to get Data 

            InputStream is = null;           //input stream
            BufferedReader Reader=null;       //wrapper character stream into cache, optimizer
            StringBuffer sbf=new StringBuffer ();  // A string variable whose object can be expanded and modified. 
            try {
                URL url=new url (params);           params as URL

con = (httpurlconnection) url.openconnection ();
Con.setconnecttimeout (5 * +);
con.setreadtimeout (5*1000);
con.setrequestproperty ("ApiKey", "5B46143955A4B1FF1B470A94315625CD");
Con.connect ();
if (Con.getresponsecode () ==200) {
is = Con.getinputstream ();
reader=new BufferedReader (New InputStreamReader (IS));
String strread=null;
While ((Strread=reader.readline ())!=null) {
sbf.append (strread);
sbf.append ("\ r \ n");
                    }
reader.close ();
return sbf.tostring ();
                }
} 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 "";

        }


    }
}

Public class Urlutil {
//Get the network interface of the channel
Public static String channelurl= "Http://apis.baidu.com/showapi_open_bus/channel_news/channel_news";
/ * Access to the network interface for Channel News
/Get Request Parameters
Channelid: news Channel ID, must match exact 
ChannelName: news channel name, can be fuzzy matching 
Title : News headlines, fuzzy matching 
page:: pages 
needcontent: need to return body 1 required 
needhtml: Whether you need to return the HTML format of body 1 required 
      */
Public static String newsurl= "Http://apis.baidu.com/showapi_open_bus/channel_news/search_news";
}

Code in the activity

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.JREDUCH07.R;

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 Apiactivity extends Appcompatactivity {
private TextView TextView; //For displaying data 
private Spinner channel; //drop-down list 
private Simpleadapter sa; //Adapter 
private list<map<string,string>> channellist; //fan type is stored in the Map,map is two string type of data 

@Override
protected void OnCreate (Bundle savedinstancestate) {
super.oncreate (savedinstancestate);
Setcontentview (R.LAYOUT.ACTIVITY_API);
textview= (TextView) Findviewbyid (R.id.textview);
channel= (Spinner) Findviewbyid (r.id.channel);
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 Getchanel (). Execute ();
Channel.setonitemselectedlistener (New Adapterview.onitemselectedlistener () {
@Override
Public void onitemselected (adapterview<?> parent, view view, int position, long id) {
map<string,string> map= channellist.get (position);
String channelname= map.get ("name");
String Channelid=map.get (channelname);
String Url=urlutil.newsurl
+ "? channelid="
+channelid+ "&channelname=" +channelname;
new Getnews (). Execute (URL);
            }

@Override
Public void onnothingselected (adapterview<?> parent) {

            }
        });


    }


//Get channel
Public class Getchanel extends asynctask<void,void,string>{
@Override
protected String doinbackground (Void ... params) {
return Httputil.httpget (urlutil.channelurl);
        }
@Override
protected void OnPostExecute (String s) {
Super.onpostexecute (s);
if (S.equals ("")) {
Toast.maketext (Getbasecontext (), "No Data", Toast.length_short). Show ();
            }
try {
Jsonobject obj=new Jsonobject (s);
jsonobject body=obj.getjsonobject ("Showapi_res_body");
Jsonarray Ja=body.getjsonarray ("channellist");
for (int i=0;i<ja.length (); i++) {
jsonobject channelobj= (jsonobject) ja.get (i);
String id=channelobj.getstring ("Channelid");
String name=channelobj.getstring ("name");
Map map=new HashMap ();
map.put ("name", name);
Map.put (name,id);
channellist.add (map);
                }
sa.notifydatasetchanged ();

} catch (Jsonexception e) {
e.printstacktrace ();
            }
        }
    }

//Get news
Public class Getnews extends asynctask<string,void,string>{
@Override
protected string Doinbackground (String ... params) {
return Httputil.httpget (Params[0]);
        }

@Override
protected void OnPostExecute (String s) {
Super.onpostexecute (s);
if (S.equals ("")) {
Textview.settext ("no");
            }
Textview.settext (s);
        }
    }

}

Obtains data from the network, parses the output.