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BufferedRead runtime crash

My app crash when encounters BufferedReader operation. Ive tried to implement the code inside an asyncTask classe, because ive read that the crash is caused by the ui thread, but nothing has changed.
public class URLConnectionReader extends AsyncTask<URL, Void, String> {
String result = null;
#Override
protected String doInBackground(URL... params) {
String result = null;
URL url = (params[0]);
try {
BufferedReader reader = new BufferedReader(
new InputStreamReader(
url.openStream()
)
);
}catch (IOException e){
e.printStackTrace();
}
return result;
}
}
Logs
03-02 13:28:43.215 25186-25186/com.example.jsonreader E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.jsonreader, PID: 25186
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.jsonreader/com.example.jsonreader.MainActivity}: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at com.android.okhttp.HostResolver$1.getAllByName(HostResolver.java:29)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:232)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:124)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:272)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:211)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:373)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:323)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:190)
at java.net.URL.openStream(URL.java:470)
at com.example.jsonreader.URLConnectionReader.doInBackground(URLConnectionReader.java:38)
at com.example.jsonreader.MainActivity.onCreate(MainActivity.java:27)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
MainActivity code
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
URL address = new URL("http://www.youth-stories.com/api/all.php");
URLConnectionReader reader = new URLConnectionReader();
String result = reader.doInBackground(address);
Toast.makeText(getApplicationContext(),result,Toast.LENGTH_LONG).show();
}catch (IOException e){
e.printStackTrace();
}

i solved the problem to get back data using the .get instruction
String result = reader.execute(address).get();

Check if Internet Connection Is Active In Android

i am trying to check for internet connection in my application.
first, i am checking if wifi or mobile data is on, then i am checking if there is an active internet connection.
what i am currently doing:
public class ConnectivityReceiver extends BroadcastReceiver {
String TAG="ConnectivityReceiver";
public static boolean hasInternetAccess() {
try {
HttpURLConnection urlc = (HttpURLConnection)
(new URL("http://clients3.google.com/generate_204")
.openConnection());
urlc.setRequestProperty("User-Agent", "Android");
urlc.setRequestProperty("Connection", "close");
urlc.setConnectTimeout(1500);
urlc.connect();
return (urlc.getResponseCode() == 204 &&
urlc.getContentLength() == 0);
} catch (IOException e) {
}
return false;
}
#Override
public void onReceive(Context arg0, Intent intent) {
String action = intent.getAction();
boolean noConnectivity = intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY,false);
if(noConnectivity){
try{
TaskListAndOptionsActivity.item3.setIcon(R.drawable.ic_action_network_nowifi);
}
catch(Exception e)
{
}
}
else
{
Boolean status = hasInternetAccess();
if(status==true)
{
try{
TaskListAndOptionsActivity.item3.setIcon(R.drawable.ic_action_network_wifi);
}
catch(Exception e)
{
}
}
else
{
try{
TaskListAndOptionsActivity.item3.setIcon(R.drawable.ic_action_network_nowifi);
}
catch(Exception e)
{
}
}
}
}
but i am getting the following error:
java.lang.RuntimeException: Unable to start receiver connectionchecker.ConnectivityReceiver: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2668)
at android.app.ActivityThread.access$1800(ActivityThread.java:172)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1384)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5653)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1166)
at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at com.android.okhttp.internal.Dns$1.getAllByName(Dns.java:28)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:216)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:122)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:390)
at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java:343)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:289)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:345)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:89)
at connectionchecker.NetworkUtil.hasInternetAccess(NetworkUtil.java:21)
at connectionchecker.ConnectivityReceiver.onReceive(ConnectivityReceiver.java:46)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:2653)
            at android.app.ActivityThread.access$1800(ActivityThread.java:172)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1384)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:146)
            at android.app.ActivityThread.main(ActivityThread.java:5653)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
            at dalvik.system.NativeStart.main(Native Method)

You are trying to connect to the network in UI thread which is not allowed. to check for active internet connection use following method.
public boolean isConnected() {
ConnectivityManager manager = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE);
NetworkInfo info = manager.getActiveNetworkInfo();
if (info != null && info.isConnected()) {
return true;
} else {
return false;
}
}
Once you receive the value, if it is true proceed with network operation. Else display the user a proper error message.

Caused by: android.os.NetworkOnMainThreadException
You need to perform network operation not on UIthread.

Sounds like you might need to use the getActiveNetworkInfo() call. There is a few posts on stackoverflow already that document it extensively so rather than repeat those have a look at these:
Detect whether there is an Internet connection available on Android

RxAndroid debounce google maps on camera change

I have an application which is using google maps and listening on camera change. My problem is that on each camera change I have to request my backend. What I want to do is just limiting the number of requests by using RxAndroid/Java to debounce.
My code looks like this:
Observable.create(new Observable.OnSubscribe<CameraPosition>() {
#Override
public void call(Subscriber<? super CameraPosition> subscriber) {
if (!subscriber.isUnsubscribed()) {
map.setOnCameraChangeListener(new GoogleMap.OnCameraChangeListener() {
#Override
public void onCameraChange(CameraPosition cameraPosition) {
subscriber.onNext(cameraPosition);
}
});
}
}
}).subscribeOn(AndroidSchedulers.mainThread())
.observeOn(AndroidSchedulers.mainThread())
.onErrorResumeNext(Observable.<CameraPosition>empty())
.debounce(1, TimeUnit.SECONDS)
.subscribe(cameraPosition -> {
final LatLngBounds item = map.getProjection().getVisibleRegion().latLngBounds;
homeActionBarActivity.getNMB().getRide().list(
item.southwest.latitude,
item.southwest.longitude,
item.northeast.latitude,
item.northeast.longitude)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.onErrorResumeNext(Observable.<List<Ride>>empty())
.subscribe(new Action1<List<Ride>>() {
#Override
public void call(List<Ride> rides) {
clearRidePointsFromMap();
for (Ride ride : rides) {
if (isAdded())
addRideStartPointToMap(ride);
}
}
});
});
As you can see, I am forcing to use the MainThread for both (subscribeOn and observeOn) but I still get this error "Not on the main thread".
Here the stacktrace:
01-27 10:59:24.049 3049-3066/com.nousmotards.android E/AndroidRuntime﹕ FATAL EXCEPTION: RxComputationThreadPool-2
Process: com.nousmotards.android, PID: 3049
java.lang.IllegalStateException: Exception thrown on Scheduler.Worker thread. Add `onError` handling.
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:52)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:864)
Caused by: rx.exceptions.OnErrorNotImplementedException: Not on the main thread
at rx.Observable$31.onError(Observable.java:7134)
at rx.observers.SafeSubscriber._onError(SafeSubscriber.java:154)
at rx.observers.SafeSubscriber.onError(SafeSubscriber.java:111)
at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:137)
at rx.observers.SerializedObserver.onNext(SerializedObserver.java:159)
at rx.observers.SerializedSubscriber.onNext(SerializedSubscriber.java:81)
at rx.internal.operators.OperatorDebounceWithTime$DebounceState.emit(OperatorDebounceWithTime.java:128)
at rx.internal.operators.OperatorDebounceWithTime$1$1.call(OperatorDebounceWithTime.java:72)
at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:47)
            at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
            at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:864)
Caused by: java.lang.IllegalStateException: Not on the main thread
at com.google.k.a.cl.b(Unknown Source)
at com.google.maps.api.android.lib6.c.ca.a(Unknown Source)
at com.google.maps.api.android.lib6.c.el.l(Unknown Source)
at com.google.android.gms.maps.internal.l.onTransact(SourceFile:312)
at android.os.Binder.transact(Binder.java:361)
at com.google.android.gms.maps.internal.IGoogleMapDelegate$a$a.getProjection(Unknown Source)
at com.google.android.gms.maps.GoogleMap.getProjection(Unknown Source)
at com.nousmotards.android.fragments.home.MapFragment.lambda$onViewCreated$33(MapFragment.java:117)
at com.nousmotards.android.fragments.home.MapFragment.access$lambda$0(MapFragment.java)
at com.nousmotards.android.fragments.home.MapFragment$$Lambda$1.call(Unknown Source)
at rx.Observable$31.onNext(Observable.java:7139)
at rx.observers.SafeSubscriber.onNext(SafeSubscriber.java:130)
            at rx.observers.SerializedObserver.onNext(SerializedObserver.java:159)
            at rx.observers.SerializedSubscriber.onNext(SerializedSubscriber.java:81)
            at rx.internal.operators.OperatorDebounceWithTime$DebounceState.emit(OperatorDebounceWithTime.java:128)
            at rx.internal.operators.OperatorDebounceWithTime$1$1.call(OperatorDebounceWithTime.java:72)
            at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:47)
            at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:422)
            at java.util.concurrent.FutureTask.run(FutureTask.java:237)
            at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:152)
            at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:265)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
            at java.lang.Thread.run(Thread.java:864)
Do you have any idea ?
Note: if I get out map.setOnCameraChangeListerner(...) from Observable.create(...) it works correctly.

Ok it seems that is (probably) due to the RxJava internal on how it is managed to pass objects from subscriber to observers. I fix my problem by simply getting LatLngBounds inside the subscriber and not the observer.
Observable.create(new Observable.OnSubscribe<LatLngBounds>() {
#Override
public void call(Subscriber<? super LatLngBounds> subscriber) {
if (!subscriber.isUnsubscribed()) {
map.setOnCameraChangeListener(cameraPosition ->
subscriber.onNext(map.getProjection().getVisibleRegion().latLngBounds));
}
}
}).subscribeOn(AndroidSchedulers.mainThread())
.observeOn(AndroidSchedulers.mainThread())
.onErrorResumeNext(Observable.<LatLngBounds>empty())
.debounce(1, TimeUnit.SECONDS)
.subscribe(item -> {
homeActionBarActivity.getNMB().getRide().list(
item.southwest.latitude,
item.southwest.longitude,
item.northeast.latitude,
item.northeast.longitude)
.subscribeOn(Schedulers.newThread())
.observeOn(AndroidSchedulers.mainThread())
.onErrorResumeNext(Observable.<List<Ride>>empty())
.subscribe(new Action1<List<Ride>>() {
#Override
public void call(List<Ride> rides) {
clearRidePointsFromMap();
for (Ride ride : rides) {
if (isAdded())
addRideStartPointToMap(ride);
}
}
});
});
Hope this will help :)

Error getting content from .txt file from URL

URL scoreU = null;
try {
scoreU = new URL("http://m.uploadedit.com/b044/1422550899503.txt");
} catch (MalformedURLException e) {
e.printStackTrace();
}
BufferedReader in = null;
try {
in = new BufferedReader(
new InputStreamReader(
scoreU.openStream()));
} catch (IOException e) {
e.printStackTrace();
}
String inputLine;
try {
while ((inputLine = in.readLine()) != null)
System.out.println(inputLine);
} catch (IOException e) {
e.printStackTrace();
}
try {
in.close();
} catch (IOException e) {
e.printStackTrace();
}
That's my code related to getting the text from the URL. It's the first time I have done this and I cannot understand my mistake. (I had to surround almost everything with a try/catch .
ERROR:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.wc.gap.worldcupfixture/com.wc.gap.worldcupfixture.MainActivity}: android.os.NetworkOnMainThreadException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1147)
at java.net.InetAddress.lookupHostByName(InetAddress.java:418)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at com.android.okhttp.HostResolver$1.getAllByName(HostResolver.java:29)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:232)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:124)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:272)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:211)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:373)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:323)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:190)
at java.net.URL.openStream(URL.java:470)
at com.wc.gap.worldcupfixture.MainActivity.onCreate(MainActivity.java:102)
at android.app.Activity.performCreate(Activity.java:5933)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
            at android.app.ActivityThread.access$800(ActivityThread.java:144)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5221)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
new InputStreamReader(scoreU.openStream()));

Android doesn't allow network requests on the main thread as it can cause UI unresponsiveness. Instead you have to do the work on a background thread, but this is pretty easy with an AsyncTask, for example:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
// ...
// Start the task here
new URLDataLoader().execute(theURL);
}
private class URLDataLoader extends AsyncTask<URL, Void, String> {
#Override
protected String doInBackground(URL... params) {
URL theURL = params[0];
// Do your network stuff here to get the data
return theData;
}
#Override
protected void onPostExecute(String data) {
// Use the data here
}
}
}

Use this code:-
try {
URL url = new URL("http://m.uploadedit.com/b044/1422550899503.txt");
URLConnection urlConnection = url.openConnection();
HttpURLConnection connection = null;
connection = (HttpURLConnection) urlConnection;
BufferedReader in = new BufferedReader(new InputStreamReader(
connection.getInputStream()));
String urlString = "";
String current;
while ((current = in.readLine()) != null) {
urlString += current;
}
System.out.println(urlString);
} catch (IOException e) {
e.printStackTrace();
}

KitKat Connection from URL get NullPointerException in AsyncTask

i'm new in java and android programming but i accepted a challenge launched by a friend and now i have to work hard.
I finally managed to have this type of activity working with AsyncTask but it seems to work well on all android but not on 4.4.2 KitKat.
The problem seems to be on url.openConnection and i tried many times to change the way in wich i do it but i haven't had positive results...
I have only to read file from an URL
This is my class code:
public class MenuActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_menu);
new HttpTask().execute();
}
public final class HttpTask
extends
AsyncTask<String/* Param */, Boolean /* Progress */, String /* Result */> {
private HttpClient mHc = new DefaultHttpClient();
#Override
protected String doInBackground(String... params) {
publishProgress(true);
InputStream inputstream = null;
URL url = null;
try {
url = new URL("http://somesite/prova.txt");
} catch (MalformedURLException e) {
e.printStackTrace();
}
assert url != null;
URLConnection connection = null;
try {
connection = url.openConnection();
} catch (IOException e) {
e.printStackTrace();
}
try {
HttpURLConnection httpConnection = (HttpURLConnection) connection;
httpConnection.setRequestMethod("GET");
httpConnection.connect();
if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
inputstream = httpConnection.getInputStream();
}
} catch (Exception ex) {
ex.printStackTrace();
}
ByteArrayOutputStream bytearryoutputstream = new ByteArrayOutputStream();
int i;
try {
i = inputstream.read();
while (i != -1) {
bytearryoutputstream.write(i);
i = inputstream.read();
}
inputstream.close();
} catch (IOException e) {
e.printStackTrace();
}
return bytearryoutputstream.toString();
}
#Override
protected void onProgressUpdate(Boolean... progress) {
}
#Override
protected void onPostExecute(String result) {
StringBuilder nuovafrase=new StringBuilder("");
String[] frasone=result.split("\n");
ListView listView = (ListView)findViewById(R.id.listViewDemo);
ArrayAdapter<String> arrayAdapter;
arrayAdapter = new ArrayAdapter<String>(getApplicationContext(), R.layout.rowmenu, R.id.textViewList, frasone);
listView.setAdapter(arrayAdapter);
}
}
}
And this is the Logcat...
03-11 17:49:37.955 1277-1294/com.example.appsb.app W/System.err﹕ atjava.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
03-11 17:49:37.955 1277-1294/com.example.appsb.app W/System.err﹕ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ at java.lang.Thread.run(Thread.java:841)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ Caused by: libcore.io.GaiException: getaddrinfo failed: EAI_NODATA (No address associated with hostname)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ at libcore.io.Posix.getaddrinfo(Native Method)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ at libcore.io.ForwardingOs.getaddrinfo(ForwardingOs.java:61)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ at java.net.InetAddress.lookupHostByName(InetAddress.java:405)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ ... 18 more
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ Caused by: libcore.io.ErrnoException: getaddrinfo failed: EACCES (Permission denied)
03-11 17:49:37.959 1277-1294/com.example.appsb.app W/System.err﹕ ... 21 more
03-11 17:49:37.963 1277-1294/com.example.appsb.app W/dalvikvm﹕ threadid=11: thread exiting with uncaught exception (group=0xa4d69b20)
03-11 17:49:37.963 1277-1294/com.example.appsb.app E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.example.appsb.app, PID: 1277
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
Caused by: java.lang.NullPointerException
at com.example.appsb.app.MenuActivity$HttpTask.doInBackground(MenuActivity.java:74)
at com.example.appsb.app.MenuActivity$HttpTask.doInBackground(MenuActivity.java:33)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
              at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
             at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
             at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
             at java.lang.Thread.run(Thread.java:841)
There is a Caused by: java.lang.NullPointerException but i cannot understand why...
Thanks

It could be caused by the inputstream being null. inputstream will only be initialized if the response code is OK. So you need to check what response code is being returned. If it is not causing the error, I'd still add some code for if the response code is not OK. You don't want your app to crash if it can't connect. You should at least display a helpful error message
Example:
else{
showErrorMsg();
return null;
}

Catch FileNotFoundException when trying inputstream.read();
try {
i = inputstream.read();
while (i != -1) {
bytearryoutputstream.write(i);
i = inputstream.read();
}
inputstream.close();
} catch (FileNotFoundException e) {
Log.e("MyTag","Handling empty page...");
} catch (IOException e) {
Log.e("MyTag",e.toString());
}