January 16, 2015

android.os.NetworkOnMainThreadException

android.os.NetworkOnMainThreadException  is an android runtime exception which occurs when you are trying to run any network or IO related operations from main activity. Android doesn't support to run IO operations directly on the main activity. 

So to avoid this exception, use a thread to do these operations or you can also use AsyncTask class which helps you to run the code in the background.

December 26, 2014

Sending Parameters to URL or web service in POST Method

Below code snippet explains how to send parameters to a web url in the POST method.
                               
URL url = new URL(“http://testulr/searchuser”);
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod(“POST”);
urlConnection.setDoOutput(true);
String params=”userid=”+userid+”&username=”+name;
OutputStream out = new BufferedOutputStream(urlConnection.getOutputStream());
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(out));
writer.write(params);
writer.flush();
out.close();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder st = new StringBuilder();
String line = "";
while ((line = reader.readLine()) != null) {
                st.append(line);
}
System.out.println("Result: "+st);
urlConnection.disconnect();
  
If the url is secured then replace HttpURLConnection class with HttpsURLConnection in the above code.

December 11, 2014

R.java file is missing in android application

While working with an android application in eclipse, some times the R.java file may missed out from the application. This is because the XML files in the app may have errors. So, resolve those errors in the XML files and then clean the project. Now the R.java file will be automatically created.