Duplicate elements in a listview

Question

I am all of a sudden getting duplicate elements in my listview. When I onClick action on the list items, everything comes back to normal. I also checked my adapter, I am not adding multiple items in the ArrayList. What can possibly be wrong here.

public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null || convertView.getTag() == null) {
            convertView = inflater.inflate(R.layout.bookingresponse_row, null);
            final CabbieViewHolder viewHolder = new CabbieViewHolder();
            viewHolder.call = (ImageView) convertView.findViewById(R.id.callCab);
            viewHolder.call.setOnClickListener(this);
            viewHolder.driverName = (TextView) convertView.findViewById(R.id.driverName);
            //SIMILAR CODE FOR MORE DATA ITEMs

            convertView.setTag(viewHolder);
        }
        // Setting all values in listview
        String temp = latestAcceptedCabbieName.get(position);
        ((CabbieViewHolder) (convertView.getTag())).driverName.setText(temp);
        ((CabbieViewHolder) (convertView.getTag())).inDetailsDriverName.setText(temp);

        //SIMIAR CODE for other data items
        // Smoothen out the list
        new AsyncTask<Object, Void, Float>() {
            CabbieViewHolder cabbieViewHolder;

            @Override
            protected Float doInBackground(Object... params) {
                float cabDistanceFromCustomer = -1.0f;
                cabbieViewHolder = (CabbieViewHolder) params[0];
                if (cabbieViewHolder.distanceFromCustomer == -1.0f) {
                    int position = (int) ((Integer) params[1]).intValue();
                    cabbieViewHolder.distanceFromCustomer = cabDistanceFromCustomer = God
                            .getGeoDistance(Double.valueOf(latestAcceptedCabbieSourceGPSX
                                    .get(position)), Double
                                    .valueOf(latestAcceptedCabbieSourceGPSY.get(position)),
                                    Double.valueOf(customerSourceLat / 1E6), Double
                                            .valueOf(customerSourceLng / 1E6));
                } else
                    cabDistanceFromCustomer = cabbieViewHolder.distanceFromCustomer;
                return cabDistanceFromCustomer;
            }

            @Override
            protected void onPostExecute(Float result) {
                super.onPostExecute(result);
                if (customerSourceLat != 0 && customerSourceLng != 0) {
                    String temp;
                    if (result != 0) {
                        temp = "Current Location @ Approx "
                                + String.format("%.1f", result / 1000) + " km";
                        cabbieViewHolder.cabDistance.setText(temp);
                        cabbieViewHolder.inDetailsCabDistance.setText(temp);
                    } else {
                        cabbieViewHolder.cabDistance.setVisibility(View.GONE);
                        cabbieViewHolder.inDetailsCabDistance.setVisibility(View.GONE);
                    }
                } else {
                    cabbieViewHolder.cabDistance.setVisibility(View.GONE);
                    cabbieViewHolder.inDetailsCabDistance.setVisibility(View.GONE);
                }
            }
        }.execute((CabbieViewHolder) convertView.getTag(), new Integer(position));
        return convertView;
    }

Answer 1

I think you're having a race condition there. You're returning convertView before it's initialized by the AsyncTask. Keep in mind that return convertView might well be executed before doInBackground is called.

I suggest you either load all view data in one AsyncTask or wait until postExecute is called to return the convertView. Or simply don't use AsyncTask if the workload is not very slow.

Answer 2

I see that you are loading the content in an asynchronous task. If the task has not completed yet you will see the old content.

Try putting a "loading data" indicator in the view so you know the data is stale in an else block that executes when convertView is not null.