Android 4.2上的HttpClient.execute（HttpPost）错误

我正在关注这个网站http://givemepass.blogspot.hk/2011/12/http-server.html尝试使用android应用程序连接PHP服务器来获取消息。

GetServerMessage.java

import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.util.EntityUtils; public class GetServerMessage { public String stringQuery(String url){ try { HttpClient httpclient = new DefaultHttpClient(); HttpPost method = new HttpPost(url); HttpResponse response = httpclient.execute(method); HttpEntity entity = response.getEntity(); if(entity != null){ return EntityUtils.toString(entity); } else{ return "No string."; } } catch(Exception e){ return "Network problem"; } } } 

GetPhpServerMessageDemoActivity.java

 import android.app.Activity; import android.os.Bundle; import android.widget.TextView; public class GetPhpServerMessageDemoActivity extends Activity { /** Called when the activity is first created. */ private TextView textView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); textView = (TextView)findViewById(R.id.text_view); GetServerMessage message = new GetServerMessage(); String msg = message.stringQuery("http://192.168.1.88/androidtesting.php"); textView.setText("Server message is "+msg); } } 

我试图从该网站下载Android应用程序项目http://uploadingit.com/file/d4632ekfpwjiupyn/GetPhpServerMessageDemo2.zip并在我的手机上运行，​​这是有效的。 但是当我开始一个新项目（Minimuim Requied SDK：API8，Target SDK：API17，Compile with：API17）并复制这两个java代码时。 我已经添加了android.permission.INTERNET权限，所以我不知道问题出在哪里，我只知道运行HttpResponse response = httpclient.execute(method); 出现错误并返回字符串“网络问题”。

Answer 1

您正在ui线程上运行与网络相关的操作。 蜂窝后你会得到NetworkOnMainThreadException 。

使用Thread或Asynctask

调用asynctask

  new TheTask().execute("http://192.168.1.88/androidtesting.php"); 

的AsyncTask

http://developer.android.com/reference/android/os/AsyncTask.html

 class TheTask extends AsyncTask { @Override protected String onPostExecute(Void result) { // TODO Auto-generated method stub super.onPostExecute(result); // update textview here textView.setText("Server message is "+result); } @Override protected void onPreExecute() { // TODO Auto-generated method stub super.onPreExecute(); } @Override protected String doInBackground(String... params) { try { HttpClient httpclient = new DefaultHttpClient(); HttpPost method = new HttpPost(params[0]); HttpResponse response = httpclient.execute(method); HttpEntity entity = response.getEntity(); if(entity != null){ return EntityUtils.toString(entity); } else{ return "No string."; } } catch(Exception e){ return "Network problem"; } } } 

在api 23中不推荐使用更新HttpClient。使用HttpUrlConnection 。

 http://developer.android.com/reference/java/net/HttpURLConnection.html 

Answer 2

Sotirios Delimanolis表示，您需要在单独的Thread上运行长时间运行的任务，如网络，呼叫。 AsyncTask可能是要走的路。