Question

当我尝试从我的PC主机中检索JSON数据时，我得到了android.os.NetworkOnMainThreadException，这是我的代码

public JSONObject getJSONObject(String url)
{
    Log.v("", "enter");
    DefaultHttpClient httpclient = new DefaultHttpClient(new BasicHttpParams());
    Log.v("", "httpclient");
    HttpPost httppost = new HttpPost(url);
    Log.v("", "httppost");
    httppost.setHeader("Content-type", "application/json");
    Log.v("", "setHeader");
    InputStream inputStream = null;
    HttpResponse response;
    try
    {
            response = httpclient.execute(httppost);
            Log.v("", "response");
            HttpEntity entity = response.getEntity();
            Log.v("", "entity");
            inputStream = entity.getContent();
            Log.v("", "inputStream");
            Log.v("", buildJSONString( inputStream ));
            return new JSONObject( buildJSONString( inputStream ) );
    }
}

来自活动的电话

JSONObject jObject = (new JSONParser(this))
                .getJSONObject("http://192.168.0.81:8080/content/test.json");

和我的logcat

09-12 12:32:05.878: V/(11103): enter
09-12 12:32:05.878: V/(11103): httpclient
09-12 12:32:05.878: V/(11103): httppost
09-12 12:32:05.878: V/(11103): setHeader
09-12 12:32:05.878: W/System.err(11103): android.os.NetworkOnMainThreadException
09-12 12:32:05.888: W/System.err(11103):    at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1108)
09-12 12:32:05.888: W/System.err(11103):    at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
09-12 12:32:05.888: W/System.err(11103):    at libcore.io.IoBridge.connectErrno(IoBridge.java:133)
09-12 12:32:05.888: W/System.err(11103):    at libcore.io.IoBridge.connect(IoBridge.java:118)
09-12 12:32:05.888: W/System.err(11103):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
09-12 12:32:05.888: W/System.err(11103):    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
09-12 12:32:05.888: W/System.err(11103):    at java.net.Socket.connect(Socket.java:849)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:154)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:580)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:512)
09-12 12:32:05.888: W/System.err(11103):    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:490)
09-12 12:32:05.888: W/System.err(11103):    at com.dwaik.jsonparser.JSONParser.getJSONObject(JSONParser.java:72)

它说我的例外是response = httpclient.execute(httppost); 我获得了互联网许可，访问服务器实际上我可以在同一个应用程序中从它下载文件有什么想法吗？

Answer 1

您不允许使用主（UI）主题进行网络操作。

有几种使用后台线程的方法。我建议使用 AsyncTask ，因为它有一个很容易理解的漂亮结构。

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

这也是一个例子：AsyncTask Android example

Google上应该提供更多功能。

Answer 2

Android NetworkOnMainThreadException

因为您在n/w operations

上正在执行 main Ui thread

使用 AsyncTask或Thread

AsyncTask： Docs

class myAsync extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
        }

        @Override
        protected Void doInBackground(Void... params) {
            // TODO Auto-generated method stub

                // Keep in mind You Can't Update UI Part here

              JSONObject jObject = (new JSONParser(this))
                .getJSONObject("http://192.168.0.81:8080/content/test.json");
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            // TODO Auto-generated method stub
            super.onPostExecute(result);
                // Handle/Update UI Part
        }
    }

称之为

new myAsync().execute();

Android NetworkOnMainThreadException

2 个答案: