Question

The application I’m building right now has problems when using HTTP post. When timeout occures, the application crashes with the following error:

06-20 19:01:35.715: E/Timeout Exception:(3802): java.net.SocketTimeoutException
06-20 19:01:35.720: W/dalvikvm(3802): threadid=15: thread exiting with uncaught exception (group=0x40c4d1f8)
06-20 19:01:35.865: D/dalvikvm(3802): GC_CONCURRENT freed 67K, 18% free 13640K/16519K, paused 7ms+3ms
06-20 19:01:35.870: E/AndroidRuntime(3802): FATAL EXCEPTION: AsyncTask #4
06-20 19:01:35.870: E/AndroidRuntime(3802): java.lang.RuntimeException: An error occured while executing doInBackground()
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.os.AsyncTask$3.done(AsyncTask.java:278)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.lang.Thread.run(Thread.java:856)
06-20 19:01:35.870: E/AndroidRuntime(3802): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.os.Handler.<init>(Handler.java:121)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.app.Dialog.<init>(Dialog.java:107)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.app.AlertDialog.<init>(AlertDialog.java:114)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.app.AlertDialog$Builder.create(AlertDialog.java:913)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.app.AlertDialog$Builder.show(AlertDialog.java:931)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at com.on_d_mand.live_evenementen.Helper.showAlert(Helper.java:357)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at com.on_d_mand.live_evenementen.SyncData.doInBackground(SyncData.java:99)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at com.on_d_mand.live_evenementen.SyncData.doInBackground(SyncData.java:1)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at android.os.AsyncTask$2.call(AsyncTask.java:264)
06-20 19:01:35.870: E/AndroidRuntime(3802):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
06-20 19:01:35.870: E/AndroidRuntime(3802):     ... 5 more

This is how the source looks like:

//ON PRE EXECUTE
protected void onPreExecute(){

    if(MESSAGE != null){
        dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
        dialog.setMessage(MESSAGE);
        dialog.setIndeterminate(true);
        dialog.setCancelable(false);
        dialog.show();
    }
}

//DO IN BACKGROUND
@Override
protected String doInBackground(String... urls) {
    //SYNC DATA WITH THE SERVER
    try{

        HttpParams httpParameters = new BasicHttpParams();
        // Set the timeout in milliseconds (30 seconds) until a connection is established.
        // The default value is zero, that means the timeout is not used. 
        int timeoutConnection = 30 * 1000;
        HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
        // Set the default socket timeout (SO_TIMEOUT) 
        // in milliseconds (30 seconds) which is the timeout for waiting for data.
        int timeoutSocket = 30 * 1000;
        HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);

        HttpClient httpclient = new DefaultHttpClient(httpParameters);
        HttpPost httppost = new HttpPost(urls[0]);
        httppost.setEntity(new UrlEncodedFormEntity(preparedInformation));
        HttpResponse response = httpclient.execute(httppost);
        HttpEntity entity = response.getEntity();
        IS = entity.getContent();

    }catch (SocketTimeoutException ste){
        Log.e("Timeout Exception: ", ste.toString());
    }
    catch(Exception e){
        Log.e("log_tag", "Error in http connection"+e.toString());
    }

    //CONVERT DATA INTO STRING
    try{
        BufferedReader reader = new BufferedReader(new InputStreamReader(IS,"iso-8859-1"),8);
            SB = new StringBuilder();
            SB.append(reader.readLine() + "\n");
            String line="0";

            while ((line = reader.readLine()) != null) {
                SB.append(line + "\n\n");
            }

            IS.close();
            this.result = SB.toString();
    }
    catch(Exception e){
        Log.e("log_tag", "Error converting result "+e.toString());
    }

    return this.result;
}

Caused by Java RuntimeException… Ok, so what? This problem needs to be avoided because it’s the very last bug in the application I have right now. Any help is MUCH appreciated.

Answer 1

You problem is show() method.

The method show() must be called from UI thread.

You are able to call this method only in onPogressUpdate() or onPostExecute() or call show() before you execute task. Also showAlert() you can’t call in doInBackground().

You must know that you can call nothing which update UI in background thread. So for update your UI use only onProgressUpdate() method or like i meant onPostExecute().

EDIT:

catch(Exception ex){
   Log.e("log_tag", "Error in http connection"+e.toString());
   return ex.toString();
}