Android Maps V2 with Android-Maps-Extensions add lots of markers very slow

Question

I am using android maps api v2 with the android-maps-extensions to cluster, and adding almost 1000 marker to the map. In the app's first run, I download the data from the webservice using a background thread and save in the SQLite, after this add the markers to the map. When I add these markers on the map when the map is shown the ui thread is blocked during 3 seconds, during this time is impossible to move the map and the progress bar that I use stops too.

That's the code that I use to add markers on the map:

private class ReadMarkersFromDB extends AsyncTask<String, UpdateEstacionamentoMap, ArrayList<UpdateEstacionamentoMap>> {

    @Override
    protected ArrayList<UpdateEstacionamentoMap> doInBackground(String... params) {

        EstacionamentoDAO estacionamentoDAO = new EstacionamentoDAO();

        SQLiteHelper sqh = new SQLiteHelper(getApplicationContext());
        SQLiteDatabase sqdb = sqh.getWritableDatabase();

        //Caso tenha informado a string para seleção, usa
        String selection = "";
        if(params[0] != null && !params[0].isEmpty())
        {
            selection = params[0];
        }

        //Pega todos os estacionamentos
        ArrayList<Estacionamento> estacionamentos = estacionamentoDAO.get(sqdb,selection);

        sqdb.close();
        sqh.close();

        //Armazena o que deve ser feito no mapa. Operações: Excluir, Incluir ou Atualizar os estacionamentos
        ArrayList<UpdateEstacionamentoMap> atualizarMapa = new ArrayList<UpdateEstacionamentoMap>();

        //Se não passou nenhuma string para seleção, logo retornou todos os registros e no mapa não tem nada, portanto somente inclui tudo no mapa
        if(selection == null || selection.isEmpty())
        {
            //Itera os estacionamentos retornados na consulta
            for(Estacionamento estacAux : estacionamentos)
            {
                //AQUI É ONDE MANDA INCLUIR O PIN NO MAPA
                publishProgress(new UpdateEstacionamentoMap(estacAux,null,0)); //0 = Incluir Pin do Estacionamento
            }
        }else //Se passou algum "selection" assume que já tem coisas no mapa e precisa apenas atualizar o conteúdo já existente no mapa
        {
            ...
        }

        return atualizarMapa;
    }

    @Override
    protected void onProgressUpdate(UpdateEstacionamentoMap... updateEstac)
    {
        if(updateEstac[0].operacao == 0) //Incluir pin no mapa 
        {
            //AQUI É ONDE INCLUI O PIN NO MAPA
            if(!updateEstac[0].estac.getDeletado()) //Inclui no mapa se o estacionamento não estiver deletado
                map.addMarker(options.data(updateEstac[0].estac).position(updateEstac[0].estac.getLocation()).title(updateEstac[0].estac.getNome()).snippet(updateEstac[0].estac.getEndereco()).icon(icon));
        }
        else
        {
        ...
        }

    }

    @Override
    protected void onPostExecute(ArrayList<UpdateEstacionamentoMap> estacionamentos) {


    }
}

I'm using addMarkersDinamically:

ClusteringSettings clusteringSettings = new ClusteringSettings().clusterOptionsProvider(new MyClusterOptionsProvider(getResources()));
clusteringSettings.addMarkersDynamically(true); //Adiciona os pins somente na região visível pelo usuário

double clusterSize = 70; //Configuração para considerar dois pontos um cluster
clusteringSettings.clusterSize(clusterSize);

map.setClustering(clusteringSettings);

The problem occur only in the first run!! After download the data, when the app opens I read from the SQLite and it's very fast, when the maps is shown, the markers already are on the map without any delay. PERFECT!!

I think the problem is when the markers are put on the map after the map is shown. I saw that the time spend to read markers from DB and add on the map is usually 800 ms.

I tried these things:

1. Add markers in the onPostExecute
2. Create BitmapDescriptor once

How to make these add markers without block the UI thread? All the read and download I already did in background thread, but add markers needs to be executed in the UI thread! Is it correct? Is there a way to add these markers in a background thread? How do I fix or do a workaround?

P.s: Sorry because my bad english, I'm learning android and English simultaneously!! =D

Thanks

Answer 1

The problem with your code seems to be calling publishProgress in a loop. Instead do that loop in onPostExecute.