Question

I am using the Jackson JSON parser as I heard it was a lot more efficient than the default Android parser. I learned how to use it off this tutorial here

http://www.mkyong.com/java/jackson-streaming-api-to-read-and-write-json/

which is great tutorial if anyone wants to learn how to use Jackson json parser.

However, I am having an issue in that I can parse data fine in Java from a URL, however when I use Jackson with Android, I get null values or the screen just shows up black for some reason.

In order to retrieve the data from the website I am using this code from here

http://www.javacodegeeks.com/2011/01/android-json-parsing-gson-tutorial.html

  private InputStream retrieveStream(String url) {

    DefaultHttpClient client = new DefaultHttpClient(); 

    HttpGet getRequest = new HttpGet(url);

    try {

       HttpResponse getResponse = client.execute(getRequest);
       final int statusCode = getResponse.getStatusLine().getStatusCode();

       if (statusCode != HttpStatus.SC_OK) { 
          Log.w(getClass().getSimpleName(), 
              "Error " + statusCode + " for URL " + url); 
          return null;
       }

       HttpEntity getResponseEntity = getResponse.getEntity();
       return getResponseEntity.getContent();

    } 
    catch (IOException e) {
       getRequest.abort();
       Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
    }

    return null;

 }

Then in my parse data method

        InputStream source = retrieveStream(url);

    try {

        JsonFactory jfactory = new JsonFactory();


        JsonParser jParser = jfactory.createJsonParser(source);

Then I parse data as was shown in the tutorial I linked above

    while (jParser.nextToken() != JsonToken.END_OBJECT) {

            String fieldname = jParser.getCurrentName();
            if ("Name".equals(fieldname)) {
                jParser.nextToken();
                this.setName(jParser.getText());
            }
            if ("Number".equals(fieldname)) {
                jParser.nextToken();
                this.setNumber(jParser.getText());
            }
        }

The url I am using is a dummy site set up which just has a JSON file on it which I am using to practice Jackson JSON parsing.

Now I know my parse data code is fine, as I in normal Java class, I can parse the data from the website using the code I created, and it works fine.

However if I try to use the code in Android with the code I have just shown, I just get a black screen for some odd reason. I have internet permissions enabled in manifest

Is there something wrong with the http code I have used? If so could someone show me how it should be done? And also why I am getting a black screen, I don’t understand why it would show that.

Thanks in advance

Answer 1

I found the issue, the link was local host which could not be accessed from Emulator. Settings were changed, and can now access link, works perfectly now 😀