Android: UnknownHostException

Question

I am using Android SDK 2.2, testing my application with the emulator. I want to send a HTTP Post. When I do I get a UnknownHostException. I have placed the required permissions
<uses-permission android:name="android.permission.INTERNET" />
in the manifest.xml. Also I can open the browser on the emulator and navigate to the URL with no problem.

Here is my code:

HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost( uri );
HttpResponse response = null;
try
{
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
2 );
nameValuePairs.add( new BasicNameValuePair( "id", "edit-name" ) );
nameValuePairs
.add( new BasicNameValuePair( "stringdata", userName ) );
httppost.setEntity( new UrlEncodedFormEntity( nameValuePairs ) );

// Execute HTTP Post Request
response = httpclient.execute( httppost );
// Log.i( "HttpManager:", "======> response: "
// + response.getEntity().getContent() );

}
catch (ClientProtocolException e)
{
Log.e( "HttpManager", "ClientProtocolException thrown" + e );
}
catch (IOException e)
{
Log.e( "HttpManager", "IOException thrown" + e );
}

`} catch(Exception e) { System.out.println("Error:"+e); } catch (ClientProtocolException e) { Log.e( "HttpManager", "ClientProtocolException thrown" + e ); } catch (IOException e) { Log.e( "HttpManager", "IOException thrown" + e ); }` This Shows error says as already handled exception. — Abdulla Sirajudeen, Jun 25 '16 at 18:50

score 116 · Answer 1 · edited Jun 14 '21 at 10:03

116

The INTERNET permission tag is a child of the manifest tag, not the application tag.

edited Jun 14 '21 at 10:03

Nimantha

6,405
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answered Jul 29 '10 at 22:13

anisbet

2,662
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20
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1

For other newbies like me, add following in your Manifest somewhere right after : – Alex Rashkov Nov 20 '11 at 20:49

score 51 · Answer 2 · edited Jun 14 '21 at 10:03

51

For others' consideration, I ran in to this problem and a Google landed me. As mentioned by anisbet, I double checked my permission tag and it was in the right spot.

I eventually fired up the android built in browser and was getting the same response from my web server as well as Google.com (while the computer itself was fine). I terminated the android emulator and restarted; worked on the first try.

After reviewing your code, it may be worth while to restart the emulator. In all fairness to the emulator, a bunch of programs crashed shortly after doing this, so perhaps something else was going on in my computer. Still, this wasted a ton of time for me so perhaps this will save someone the headache I went though.

edited Jun 14 '21 at 10:03

Nimantha

6,405
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answered Feb 21 '11 at 22:50

Frank V

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144

Same works for debugging on an actual device—just restart it :) – MSpeed Nov 23 '11 at 14:01
The Android Emulator doesn't seem to like some network changes, even the Intel HAXM-accelerated Gingerbread one. If I move from one WiFi network to one powered by a MiFi, it gives me this error and I end up restarting the Emulator. – louielouie Jun 10 '12 at 00:19

score 35 · Answer 3 · answered Nov 02 '12 at 19:01

35

Make sure you have an internet connection. That's what happened to me when I forgot I am testing with mobile phone with no internet connection.

answered Nov 02 '12 at 19:01

igo

6,359
6
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2

Oh wow i cant believe this was my problem! make sure wifi is on when using extra test devices guys! thanks – Glenn.nz May 16 '13 at 00:08
Yes, I was assuming the internet was going via the debugging cable along USB but of course, it goes directly from the phone! – Lukos Jun 17 '13 at 12:54

score 17 · Answer 4 · answered Jan 17 '12 at 11:07

17

You know what solved it for me was putting the permission just before the closing manifest tag, like so:

<uses-permission android:name="android.permission.INTERNET" />
</manifest>

answered Jan 17 '12 at 11:07

Moritz

3,235
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score 9 · Answer 5 · edited Aug 03 '17 at 09:15

9

It happens sometimes when you are running app in the emulator. Just restart the emulator will solve the problem. It worked for me !

edited Aug 03 '17 at 09:15

Alexis Wilke

19,179
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answered Mar 28 '13 at 10:00

java dev

1,044
1
11
17

score 5 · Answer 6 · answered Feb 09 '12 at 16:17

5

If none of the above worked, try taking a step back and making sure that your device or emulator can actually reach the internet by opening up a browser.

answered Feb 09 '12 at 16:17

diadyne

4,038
36
28

score 2 · Answer 7 · answered Dec 11 '14 at 04:55

2

A final check would be that your domain name is a valid domain. Having a underscore in a domain is invalid and will throw an unknown host exception.

answered Dec 11 '14 at 04:55

tlunter

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This is a rare issue but is really annoying! See explanation [here](http://stackoverflow.com/a/11206362/465942) – Kapé Mar 24 '15 at 14:57

score 2 · Answer 8 · answered Feb 09 '11 at 20:33

2

I ran into a similar problem when testing an app that had a minSdkVersion set to 4 and I was trying to run it on a G1. Changing it to 3 solved the problem for me.

answered Feb 09 '11 at 20:33

metric152

422
4
16

pretty weird but i had exactly the same problem and changing de minSdkVersion fixed the problem for me aswell – Mark Mooibroek Oct 11 '11 at 20:21
This worked for me too. I had minSdkVersion="7". I set it to "6" and it worked. – Gagege Jul 26 '12 at 18:51

score 2 · Answer 9 · answered Jun 17 '11 at 16:03

I ran in to the same issue. I have the correct permissions in my Android Manifest file and the Url is correct too. I am getting the response in the web browser. I restarted the IDE, Emulator, but didn't fix the problem. So i deleted the AVD using AVD manager and then started the emulator and it started to work.

score 1 · Answer 10 · answered May 14 '12 at 17:07

1

One other thing: It turned out that the internet itself wasn't working for me. Launching the emulator from the commandline with these switches fixed it for me: emulator -avd your_avd_name -dns-server 8.8.8.8

answered May 14 '12 at 17:07

Tejaswi Yerukalapudi

8,987
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score 0 · Answer 11 · answered Sep 25 '14 at 18:37

0

I've seen this error when connected to WiFi. As soon as I turned off WiFi, it worked. UnknownHostException could very well be thrown due to this Android bug:

http://code.google.com/p/android/issues/detail?id=67324

answered Sep 25 '14 at 18:37

l33t

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score 0 · Answer 12 · answered Jul 09 '15 at 03:16

0

Check this also if you're not using Emulator

I got the same issue today, i am not using Emulator but enabled USB debugging in mobile for testing.

I didn't turn on data in my mobile, so i got UnknownHostException, once I turn-on it got resolved.

answered Jul 09 '15 at 03:16

Saravana

12,647
2
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score 0 · Answer 13 · answered Aug 25 '15 at 09:15

0

If you open a VPN, "Unknown host exception" may be the result

answered Aug 25 '15 at 09:15

Francis Shi

395
4
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score 0 · Answer 14 · answered Jul 05 '16 at 04:48

0

I ran into same problem when using emulator, because I changed wifi on my laptop so restarting the wifi of emulator solved my problem.

answered Jul 05 '16 at 04:48

Sana

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Android: UnknownHostException

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