CODEWITHSUNDEEP
javaandroidmultithreadinggpslooper
mkyong
mkyong

Reputation: 12947

Create New Thread - Android

I'm trying to implement a looper so I can create a thread for sending GPS coordinates to a database. I'm new to Java and this is all really confusing, but maybe you can help. The following class method is called by the main activity when a button is pressed. The method finds the GPS location and then sends it to a different class's method that sends the latitude and longitude (along with the user id) to a database. I'm having trouble with my app slowing down and freezing at times, so it appears I need to implement some way to create a new thread for this process. Any ideas. I'm a noob so be gentle. Here is my code:

    public class LocationActivity extends Thread{

    private LocationManager locManager;
    private LocationListener locListener;

    public void startLocation(Context context, String usr_id2)
    {   
        final String usr = usr_id2;

    //get a reference to the LocationManager
    locManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);


    //checked to receive updates from the position
    locListener = new LocationListener() {
        public void onLocationChanged(Location location) {
            SendActivity.send(location, usr);
        }
        public void onProviderDisabled(String provider){
            //labelState.setText("Provider OFF");
        }
        public void onProviderEnabled(String provider){
            //labelState.setText("Provider ON ");
        }
        public void onStatusChanged(String provider, int status, Bundle extras){
            //Log.i("", "Provider Status: " + status);
            }
        };

        Looper looper = null;
        locManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locListener, looper);
    }
}

One other question, would I add the looper here or in the class that actually sends the information to the database? It uses HTTP Post to send to a PHP program that adds the info to a MySQL database.

Upvotes: 0

Views: 3229

Answers (3)

Stephan Celis
Stephan Celis

Reputation: 2612

You can't access the 'context' or any UI object from a custom thread. This is because these are made in the main UI thread and you can't access these objects from your thread.

Just as Martyn said, you need to create a AsyncTask or use Handlers to access the context/ui.

In your case, go for the AsyncTask

Upvotes: 0

Egor
Egor

Reputation: 40203

You should consider using AsyncTask class for such operations, it's pretty easy to use and it provides a simple way of synchronizing with the UI thread. Here's a nice post about threading in Android, you can learn more about AsyncTask in the Android docs. Hope this helps.

Upvotes: 1

Martyn
Martyn

Reputation: 16622

I would be tempted to try a different tactic here. Android has a class called AsynTask which is written to ease the burden on developers of offloading work to be done on a thread.

AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.

In terms of writing to the DB and sending data back to a server, I would look at using a Service, but remember that the only Service that doesn't natively run on the UI thread is the IntentService

Upvotes: 4

Related Questions