HTTP doesn't work in Android emulator
android, http
Solution
If you look at this Android documentation, it explains
NetworkOnMainThreadException:
The exception that is thrown when an application attempts to perform a networking operation on its main thread.
This is only thrown for applications targeting the Honeycomb SDK or higher. Applications targeting earlier SDK versions are allowed to do networking on their main event loop threads, but it's heavily discouraged.
So, depending on OS version, there may be enforcement (exception throwing) of the policy that you not make network requests on the UI thread. This could explain why your code works on a device, and not on an emulator (if they have different Android versions).
You could change the `ThreadPolicy`. But as an alternative, I'd suggest you look again at the statement in the Android docs. They heavily discourage performing network operations on the main thread, and I'd certainly agree with them.
So, rather than changing the policy to make it legal, you might consider changing your code, so that your `getResponse()` method is not called on the UI thread.
Typically, you would use AsyncTask to do the work in the background.
Problem
I tried multiple HTTP classes (`HttpURLConnection`, `HTTPClient` and others) but they don't work in emulator. Then I decided to test that on my phone and it worked well! So how can I fix this strange behaviour of Android emulator that HTTP classes don't work (while browser can work)? They crash an application at all. Here is my code: ``` public static SimpleXML getResponse(String action, Map<String, String> params) { // Create a new HttpClient and Post Header HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost(action); try { // Add your data List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(params.size()); for(Map.Entry<String, String> heh : params.entrySet()) nameValuePairs.add(new BasicNameValuePair(heh.getKey(), heh.getValue())); httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); // Execute HTTP Post Request HttpResponse response = httpclient.execute(httppost); return SimpleXML.loadXml(response.getEntity().getContent()); } catch (ClientProtocolException e) { return null; } catch (IOException e) { return null; } } ``` LogCat log: ``` 06-30 22:07:28.972: E/AndroidRuntime(682): FATAL EXCEPTION: main 06-30 22:07:28.972: E/AndroidRuntime(682): android.os.NetworkOnMainThreadException 06-30 22:07:28.972: E/AndroidRuntime(682): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 06-30 22:07:28.972: E/AndroidRuntime(682): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 06-30 22:07:28.972: E/AndroidRuntime(682): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 06-30 22:07:28.972: E/AndroidRuntime(682): at java.net.InetAddress.getAllByName(InetAddress.java:214) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 06-30 22:07:28.972: E/AndroidRuntime(682): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 06-30 22:07:28.972: E/AndroidRuntime(682): at net.ekvium.air.API.getResponse(API.java:98) 06-30 22:07:28.972: E/AndroidRuntime(682): at net.ekvium.air.MainActivity$1.onClick(MainActivity.java:62) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.view.View.performClick(View.java:4084) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.view.View$PerformClick.run(View.java:16966) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.os.Handler.handleCallback(Handler.java:615) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.os.Handler.dispatchMessage(Handler.java:92) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.os.Looper.loop(Looper.java:137) 06-30 22:07:28.972: E/AndroidRuntime(682): at android.app.ActivityThread.main(ActivityThread.java:4745) 06-30 22:07:28.972: E/AndroidRuntime(682): at java.lang.reflect.Method.invokeNative(Native Method) 06-30 22:07:28.972: E/AndroidRuntime(682): at java.lang.reflect.Method.invoke(Method.java:511) 06-30 22:07:28.972: E/AndroidRuntime(682): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 06-30 22:07:28.972: E/AndroidRuntime(682): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 06-30 22:07:28.972: E/AndroidRuntime(682): at dalvik.system.NativeStart.main(Native Method) ```