ProgressBar in asynctask is not showing on upload

Question

Can someone tell me, why progressbar isnt showing when picture is being uploaded. I copied asynctask structure from my old project where it works. In my old project i use as

Answer 1

Run on ui thread in asynctask doinbackground() is not correct. Also you are returning null in doInBackground() and you have parameter file_url in onPostExecute(). Return value in doInbackground() recieve value in onPostExecute().

doInBackGround() runs in background so you cannot access or update ui here.

To update ui you can use onPostExecute().

Your AsyncTask should be something like below. You are doing it the wrong way.

http://developer.android.com/reference/android/os/AsyncTask.html. See the topic under The 4 steps

 pd= new ProgressDialog(this);
 pd.setTitle("Posting data");
 new PostTask().execute();

private class PostTask extends AsyncTask<VOid, Void, Void> {

protected void onPreExecute()
{//display dialog.
  pd.show();
}
protected SoapObject doInBackground(Void... params) {
// TODO Auto-generated method stub
       //post request. do not update ui here. runs in background
return null;
}

protected void onPostExecute(Void param)
{   

 pd.dismiss();
 //update ui here
}

Answer 2

I found this library which is perfect to accomplish the upload task and also provide a progress handler which could be used to set the value of a ProgressBar:

https://github.com/nadam/android-async-http

It could be used like the following... Set onClickHandler for the upload Button:

@Override
public void onClick(View arg0) {
    try {
        String url = Uri.parse("YOUR UPLOAD URL GOES HERE")
                .buildUpon()
                .appendQueryParameter("SOME PARAMETER IF NEEDED 01", "VALUE 01")
                .appendQueryParameter("SOME PARAMETER IF NEEDED 02", "VALUE 02")
                .build().toString();

        AsyncHttpResponseHandler httpResponseHandler = createHTTPResponseHandler();

        RequestParams params = new RequestParams();
        // this path could be retrieved from library or camera
        String imageFilePath = "/storage/sdcard/DCIM/Camera/IMG.jpg";
        params.put("data", new File(imageFilePath));

        AsyncHttpClient client = new AsyncHttpClient();
        client.post(url, params, httpResponseHandler);
    } catch (IOException e) {
        e.printStackTrace();                
    }
}

then add this method to your activity code:

public AsyncHttpResponseHandler createHTTPResponseHandler() {
    AsyncHttpResponseHandler handler = new AsyncHttpResponseHandler() {
        @Override
        public void onStart() {
            super.onStart();
        }

        @Override
        public void onProgress(int position, int length) {
            super.onProgress(position, length);

            progressBar.setProgress(position);
            progressBar.setMax(length);
        }

        @Override
        public void onSuccess(String content) {
            super.onSuccess(content);
        }

        @Override
        public void onFailure(Throwable error, String content) {
            super.onFailure(error, content);
        }

        @Override
        public void onFinish() {
            super.onFinish();
        }
    };

    return handler;
}