title: how to convert AsyncTask to RxAndroid
body: <p>I am new to rxandroid, now I want to use rxandroid to access internet with out use AsyncTask, I have write some code below</p>
  
  <p>```</p>
  
  <pre><code> Observable&lt;String&gt; o= Observable.create(new Observable.OnSubscribe&lt;String&gt;() {
  
         @Override
         public void call(Subscriber&lt;? super String&gt; sub) {
             sub.onNext("http://192.168.191.1/test3.html");//The test url in my computer ,it works ok;
         }
     });
      Subscriber&lt;String&gt; mySubscriber = new Subscriber&lt;String&gt;() {
          @Override
          public void onNext(String s) {
              InputStream in = null;
              try {
                  in = new URL(s).openStream();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              Reader r = null;
              try {
                  r = new InputStreamReader(in, "utf-8");
              } catch (UnsupportedEncodingException e) {
                  e.printStackTrace();
              }
              char[] buffer = new char[8000];
              try {
                  r.read(buffer);
              } catch (IOException e) {
                  e.printStackTrace();
              }
              Log.d("AAA", new String(buffer));
          }
  
          @Override
          public void onCompleted() { }
  
          @Override
          public void onError(Throwable e) { }
      };
      o.subscribeOn(Schedulers.io())
              .observeOn(AndroidSchedulers.mainThread())
              .subscribe(mySubscriber);
  </code></pre>
  
  <p>```</p>
  
  <p>It haven't cause any crash, but I can not get any output, anyone know how to solve it? Thank you very much.</p>