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up vote 0 down vote favorite

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();
          }
share|improve this question
    
on a separate note, you are trying to call openConnection on an object that might be null. you aren't catching a nullpointerexception so that may cause you problems down the road. you should probably move the whole thing into a single try block with 2 catch blocks. – toadzky Oct 18 '12 at 16:24
    
yea thanks, i planned to tidy it up when i get some working code, for now it can access the php and should be able to access the url/jpg – user1417337 Oct 18 '12 at 16:25
    
are there any logs on the server side that might help? – toadzky Oct 18 '12 at 16:26
    
no, the php on the server side is called and gives url back to code and the code then moves to the httpurlconnection lines and freezes at conn.connect – user1417337 Oct 18 '12 at 16:27
    
Try run in debug mode to see where it freezes. You can pause the application when it freezes and check all threads. – Danpe Oct 18 '12 at 16:27
up vote -1 down vote accepted

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.

share|improve this answer
    
will do, hold for results :) – user1417337 Oct 18 '12 at 16:48
    
same problem except at next line of code - int length = conn.getContentLength(); – user1417337 Oct 18 '12 at 16:50
    
Add debug logging or set a breakpoint in the debugger and see what the value of myFileUrl is when you call myFileUrl.openConnection(). – David Wasser Oct 18 '12 at 16:54
    
i already did 0- the myfileUrl is correct and i can browse to it :( – user1417337 Oct 18 '12 at 16:57
    
Can you check the server logs and see if the request actually arrives at the server? If not, can you use a network sniffer to see if the HTTP request is sent to the server? It looks like the server isn't responding. – David Wasser Oct 18 '12 at 16:58
up vote 1 down vote

First of all make sure you added Internet Permission to manifest:

<uses-permission android:name="android.permission.INTERNET" />

outside the application tag in your AndroidManifest.xml

Troubleshooting:

  1. Try access the same URL using your browser
  2. Check if you are not behind proxy or server is not behind proxy
  3. Try pinging the server see and check the latency.
  4. Try catching all exceptions:

Change } catch (IOException e) { to } catch (Exception e) {

If all looks good try this code:

System.setProperty("http.keepAlive", "false");
HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
conn.setUseCaches(false); 
conn.setConnectTimeout(30000);
conn.setDoOutput(true); 
conn.setDoInput(true); 

//conn.connect(); // You are allready connected after openConnection().

If still no luck, try using HttpClient & HttpGet this way:

final HttpClient client = new DefaultHttpClient();
final HttpGet conn = new HttpGet(myFileUrl.toString());

HttpResponse response = client.execute(conn);
InputStream is = response.getEntity().getContent();
share|improve this answer
    
Hey @Danpe.Troubleshooting: Try access the same URL using your browser - yes i can Check if you are not behind proxy or server is not behind proxy - i am behind a firewall but this didnt affect the code when i was running on ui thread.i thenadded the php code on background thread which worked and then moved my internet url code to that background thread which caused issue Try pinging the server see and check the latency. Try catching all exceptions: Change } catch (IOException e) { to } catch (Exception e) { - testing this now ... :) Let me know what did you found out. – user1417337 Oct 18 '12 at 16:36
    
IOException e to Exception e -> i get same result, debugger just sits at the conn.connect forever. Dialog UI still spinning – user1417337 Oct 18 '12 at 16:42
    
Try the new snippets i posted, let me know what you get :) – Danpe Oct 18 '12 at 16:43
    
I WILL THX just reading them now – user1417337 Oct 18 '12 at 16:50
    
hey what is the useragent variable? its notdeclared? – user1417337 Oct 18 '12 at 17:03

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