Fetching data from Internet in background and showing ProgressDialog or ProgressBar

Question

hi all,

I am developing an application which require accessing a website for data, and will show that data on device. I wants to fetch data from Internet in background and show ProgressDialog or ProgressBar on device and when application receive response from server app will dismiss the dialog or bar and will show data .

For this i am using AsyncTask -

code for AsyncTask is as follows--

ServerTask extends AsyncTask { @Override protected void onPreExecute() { dialogAccessingServer = new ProgressDialog(ctx); dialogAccessingServer.setMessage(shownOnProgressDialog); dialogAccessingSpurstone.show(); }

    @Override
    protected ServerResponse doInBackground(String... urlArray) {

            String urlString = urlArray[0];
            HttpResponse serverResponseObject = null;

            //finding HttpResponse

            return serverResponseObject;

    }//end of doInBackground

    @Override
    protected void onPostExecute(HttpResponse serverResponseObject){
            dialogAccessingSpurstone.dismiss();

    }

}

and calling this code as follows--

ServerTask serverTaskObject = new ServerTask(); serverTaskObject.execute(); HttpResponse response = serverTaskObject.get();

//performing operation on response

but ProgressDialog is not shown.(I guess the reason for it is the thread is not complete and android invalidate only when thread has completed).

My Questions -- 1- If my guess is right ? If yes then how I should implement it? 2- If there is any other better way to do this?

thanks

Answer 1

Following is a template code that displays a ProgressDialog while a task is executing in background:

class GetTask extends AsyncTask<Object, Void, String>
    {
        Context mContext;
            ProgressDialog mDialog = null;

            GetPhotoFeedTask(Context context)
    {
        mContext = context;
    }

        @Override
        protected void onPreExecute()
        {
            super.onPreExecute();

             mDialog = new ProgressDialog(mContext);
             mDialog.setMessage("Please wait...");
             mDialog.show();
        }
                @Override
        protected String doInBackground(Object... params)
        {
                  // do stuff in background : fetch response
                }

                @Override
        protected void onPostExecute(String result)
        {
            super.onPostExecute(result);
            setProgressBarIndeterminateVisibility(false);
            // mDialog.dismiss();
                }
}

and you invoke it from your activity using new GetTask(this).execute() statement;

Note: Note that while displaying a ProgressDialog if the user switches the Orientation or causes event that ensues one, the code might break. It is advised to use Managed Dialogs for such cases.