Question

I suspect I’m running into some issues borne out of threading in my simple Android app.

I have a Activity which does the following:

1. runs a dialog on main thread
2. spins a background thread and hits a PHP script for retreiving data using DefaultHttpClient and close this connection. This successfully returns a URL to a picture on the internet
3. open HttpUrlConnection called conn and try conn.connect
4. app freezes at this point with no error

Not sure what code to put here, I could paste it all but that would be too much so let me know if any more info is needed:

/**
 * Background Async Task to Load all Question by making HTTP Request
 */
class LoadAllImages extends AsyncTask<String, String, String> {
  /**
   * Before starting background thread Show Progress Dialog
   * */
  @Override
  protected void onPreExecute() {
    super.onPreExecute();
    // dialog init'd here
  }

  @Override
  protected String doInBackground(String... args) {
    // Building Parameters
    List<NameValuePair> params = new ArrayList<NameValuePair>();
    // getting JSON string from URL
    JSONObject json = jParser.makeHttpRequest(url_question_details, "GET", params);



    // Check your log cat for JSON response
    Log.d("All Questions: ", json.toString());

    try {

        // images found
        // Getting Array of questions
        images = json.getJSONArray(TAG_IMAGES);

        // looping through All questions
        for (int i = 0; i < images.length(); i++) {
          JSONObject c = images.getJSONObject(i);

          // Storing each json item in variable
          String id = c.getString(TAG_IMAGEID);
          String location = c.getString(TAG_IMAGELOCATION);

          URL myFileUrl = null;
          try {
            myFileUrl = new URL(location);
          } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
          }
          try {
            HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
            conn.setDoInput(true);
            conn.connect(); // freezes here
            int length = conn.getContentLength();
            int[] bitmapData = new int[length];
            byte[] bitmapData2 = new byte[length];
            InputStream is = conn.getInputStream();
          } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
          }

Answer 1

Remove these 2 lines:

conn.setDoInput(true);
conn.connect(); // freezes here

When you do this:

HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
int length = conn.getContentLength();

You are already connected. Calling conn.getContentLength() causes HttpURLConnection to make the connection, sends the request and fetches the response. You don’t need to explicitly connect. You also don’t need to call setDoInput(true) since that is the default setting.