为什么将网络访问放到另一个线程之后还是出现android.os.NetworkOnMainThreadException异常

小小白龙马 2014-03-27 10:28:30

package dragon.location.google;



import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;



import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.DefaultHttpClient;



import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;



import com.google.gson.Gson;



public class MainActivity extends Activity {

	private Button geocodingButton = null;

    Handler handler = new Handler() {

		@Override

		public void handleMessage(Message msg) {

			super.handleMessage(msg);

			Bundle data = msg.getData();

			String val = data.getString("value");

		}

    };

    /** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        new Thread(geocodingThread).start();

    }

    

    Runnable geocodingThread = new Runnable() {

		@Override

		public void run() {

			geocodingButton = (Button)findViewById(R.id.geoButton);

	        geocodingButton.setOnClickListener(new OnClickListener(){

				@Override

				public void onClick(View v) {

					//针对上一节中Geocoder服务不可用的情况，此处使用google maps中的服务替代

					String url = "http://maps.google.com/maps/api/geocode/json?address=SFO&sensor=false";

					HttpClient client = new DefaultHttpClient();

					String resonseData = "";

					try {

						//向指定的url发送http请求

						HttpResponse response = client.execute(new HttpGet(url));

						//取得服务器返回的响应

						HttpEntity entity = response.getEntity();

						BufferedReader br = new BufferedReader(new InputStreamReader(entity.getContent()));

						String line = "";

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

							resonseData = resonseData + line;

						}

					} catch (ClientProtocolException e) {

						e.printStackTrace();

					} catch (IOException e) {

						e.printStackTrace();

					}

					Gson gson = new Gson();

					TestResult testResult = gson.fromJson(resonseData,TestResult.class);

					System.out.println(resonseData);

					System.out.println(testResult);

				}

	        });

	        Message msg = new Message();

	        Bundle data = new Bundle();

	        data.putString("value", "result");

	        msg.setData(data);

	        handler.sendMessage(msg);

		}

	};

	

/*    public static float GetSystemVersion() {

        String strVer =  android.os.Build.VERSION.RELEASE;

        strVer = strVer.substring(0, 3).trim();

        float fv = Float.valueOf(strVer);

        return fv;

    }*/

	//将网络操作放在主线程的一种方法:将下面一段话放在网络操作前面

	/*				

	if (GetSystemVersion() > 2.3) {

		StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()

				.detectDiskReads().detectDiskWrites().detectNetwork()

				.penaltyLog().build());



		StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()

				.detectLeakedSqlLiteObjects().penaltyLog().penaltyDeath()

				.build());

	}*/

}