I am trying to connect to an URL address in Android to get the HTML code. I am following this tutorial. I get an error when the readStream function is called. This is the error output in the log:
11-23 20:24:22.572: W/WindowManager(151): Failure taking screenshot for (246x437) to layer 21010
11-23 20:24:23.122: W/System.err(698): android.os.NetworkOnMainThreadException
11-23 20:24:23.133: W/System.err(698): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
11-23 20:24:23.133: W/System.err(698): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
11-23 20:24:23.133: W/System.err(698): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
11-23 20:24:23.133: W/System.err(698): at java.net.InetAddress.getAllByName(InetAddress.java:214)
11-23 20:24:23.133: W/System.err(698): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
11-23 20:24:23.142: W/System.err(698): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
11-23 20:24:23.142: W/System.err(698): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:341)
11-23 20:24:23.142: W/System.err(698): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
11-23 20:24:23.153: W/System.err(698): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
11-23 20:24:23.153: W/System.err(698): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315)
11-23 20:24:23.153: W/System.err(698): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.makeSslConnection(HttpsURLConnectionImpl.java:461)
11-23 20:24:23.153: W/System.err(698): at libcore.net.http.HttpsURLConnectionImpl$HttpsEngine.connect(HttpsURLConnectionImpl.java:433)
11-23 20:24:23.162: W/System.err(698): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289)
11-23 20:24:23.162: W/System.err(698): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239)
11-23 20:24:23.162: W/System.err(698): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273)
11-23 20:24:23.162: W/System.err(698): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)
11-23 20:24:23.162: W/System.err(698): at libcore.net.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:271)
11-23 20:24:23.172: W/System.err(698): at com.example.seminarska.Prevozi.onCreate(Prevozi.java:53)
11-23 20:24:23.172: W/System.err(698): at android.app.Activity.performCreate(Activity.java:5008)
11-23 20:24:23.172: W/System.err(698): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
11-23 20:24:23.172: W/System.err(698): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
11-23 20:24:23.172: W/System.err(698): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
11-23 20:24:23.182: W/System.err(698): at android.app.ActivityThread.access$600(ActivityThread.java:130)
11-23 20:24:23.182: W/System.err(698): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
11-23 20:24:23.182: W/System.err(698): at android.os.Handler.dispatchMessage(Handler.java:99)
11-23 20:24:23.194: W/System.err(698): at android.os.Looper.loop(Looper.java:137)
11-23 20:24:23.194: W/System.err(698): at android.app.ActivityThread.main(ActivityThread.java:4745)
11-23 20:24:23.203: W/System.err(698): at java.lang.reflect.Method.invokeNative(Native Method)
11-23 20:24:23.212: W/System.err(698): at java.lang.reflect.Method.invoke(Method.java:511)
11-23 20:24:23.212: W/System.err(698): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
11-23 20:24:23.212: W/System.err(698): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-23 20:24:23.223: W/System.err(698): at dalvik.system.NativeStart.main(Native Method)
The code below is the one I am using.
try {
URL url = new URL("http://www.vogella.com");
HttpURLConnection con = (HttpURLConnection) url
.openConnection();
readStream(con.getInputStream());
} catch (Exception e) {
e.printStackTrace();
}
private void readStream(InputStream in) {
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(in));
String line = "";
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
Any ideas what is wrong? Is there a different way to connect to the web.
You are getting this error because you’re doing a network operation, like retrieving the HTML on your main UI Thread.
To fix it in the best way, move all network related code into a separate Thread or AsyncTask