it-swarm.com.de

Wie kann ich mit Google Maps Android API v2 eine Änderung an meinem Standort ändern?

Wie erhalte ich ein mit "Mein Standort" geändertes Ereignis mit Google Maps Android API v2 ?

In v1 können Sie das nächste tun, um ein geändertes Ereignis zu behandeln:

public class MyLocationOverlay extends com.google.Android.maps.MyLocationOverlay {

    /**
     * Listener
     */
    public interface Listener {
        void onLocationChanged(Android.location.Location location);
    }

    private Listener listener;

    public MyLocationOverlay(Context context, MapView mapView, Listener listener) {
        super(context, mapView);

        this.listener = listener;
    }

    @Override
    public synchronized void onLocationChanged(Location location) {
        super.onLocationChanged(location);

        // fire listener
        if (listener != null)
            listener.onLocationChanged(location);
    }
}
15
4ntoine

UPDATE: Google hat die neue LocationClient und die zugehörige LocationListener eingeführt (die OnMyLocationChangeListener-Schnittstelle ist nun veraltet).


Sie können dies tun, indem Sie eine benutzerdefinierte LocationSource für die my-location-Ebene erstellen. Im Folgenden wird ein Beispiel dargestellt, bei dem die Kamera automatisch am aktuellen Standort ("Mein Standort") zentriert wird. Dies ähnelt der Funktionalität, die MyLocationOverlay in Google Maps Android API v1 angeboten hat.

Sie können diese Codezeile also einfach ersetzen

mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(location.getLatitude(), location.getLongitude())));

mit welcher Funktionalität Sie auch ausgeführt werden müssen, wenn sich der Standort ändert.

public class PlaceMapFragment extends SupportMapFragment {

    // Note that this may be null if the Google Play services APK is not available.
    private GoogleMap mMap;

    protected PlaceActivity activity;
    private FollowMeLocationSource followMeLocationSource;
    private Context mContext;

    /* We need the Context in order to get a reference to the Location Manager
     * (when instantiating this fragment from your activity use:
     *  PlaceMapFragment mapFragment = new PlaceMapFragment(this); ) */
    public PlaceMapFragment(Context context) {
        this.mContext = context;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        activity = (PlaceActivity)getActivity();
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // creates our custom LocationSource and initializes some of its members
        followMeLocationSource = new FollowMeLocationSource();

        /* We can't be guaranteed that the map is available because Google Play services might not be available.
         * (un-comment the following line when using this code in a FragmentActivity / Activity 
         *  to try get a reference to the map here !) */
        //setUpMapIfNeeded();
    }

    @Override
    public void onResume() {
        super.onResume();

        /* We query for the best Location Provider everytime this fragment is displayed
         * just in case a better provider might have become available since we last displayed it */
        followMeLocationSource.getBestAvailableProvider();

        // Get a reference to the map/GoogleMap object
        setUpMapIfNeeded();

        /* Enable the my-location layer (this causes our LocationSource to be automatically activated.)
         * While enabled, the my-location layer continuously draws an indication of a user's
         * current location and bearing, and displays UI controls that allow a user to interact
         * with their location (for example, to enable or disable camera tracking of their location and bearing).*/
        mMap.setMyLocationEnabled(true);
    }

    @Override
    public void onPause() {
        /* Disable the my-location layer (this causes our LocationSource to be automatically deactivated.) */
        mMap.setMyLocationEnabled(false);

        super.onPause();
    }

    /**
     * Sets up the map if it is possible to do so (i.e., the Google Play services APK is correctly
     * installed) and the map has not already been instantiated. This will ensure that we only ever
     * manipulate the map once when it {@link #mMap} is not null.
     * <p>
     * If it isn't installed {@link SupportMapFragment} (and {@link com.google.Android.gms.maps.MapView
     * MapView}) will show a Prompt for the user to install/update the Google Play services APK on their device.
     */
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            mMap = getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                // The Map is verified. It is now safe to manipulate the map:

                // Replace the (default) location source of the my-location layer with our custom LocationSource
                mMap.setLocationSource(followMeLocationSource);

                // Set default zoom
                mMap.moveCamera(CameraUpdateFactory.zoomTo(15f));
            }
        }
    }

    /* Our custom LocationSource. 
     * We register this class to receive location updates from the Location Manager
     * and for that reason we need to also implement the LocationListener interface. */
    private class FollowMeLocationSource implements LocationSource, LocationListener {

        private OnLocationChangedListener mListener;
        private LocationManager locationManager;
        private final Criteria criteria = new Criteria();
        private String bestAvailableProvider;
        /* Updates are restricted to one every 10 seconds, and only when
         * movement of more than 10 meters has been detected.*/
        private final int minTime = 10000;     // minimum time interval between location updates, in milliseconds
        private final int minDistance = 10;    // minimum distance between location updates, in meters

        private FollowMeLocationSource() {
            // Get reference to Location Manager
            locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);

            // Specify Location Provider criteria
            criteria.setAccuracy(Criteria.ACCURACY_FINE);
            criteria.setPowerRequirement(Criteria.POWER_LOW);
            criteria.setAltitudeRequired(true);
            criteria.setBearingRequired(true);
            criteria.setSpeedRequired(true);
            criteria.setCostAllowed(true);
        }

        private void getBestAvailableProvider() {
            /* The preffered way of specifying the location provider (e.g. GPS, NETWORK) to use 
             * is to ask the Location Manager for the one that best satisfies our criteria.
             * By passing the 'true' boolean we ask for the best available (enabled) provider. */
            bestAvailableProvider = locationManager.getBestProvider(criteria, true);
        }

        /* Activates this provider. This provider will notify the supplied listener
         * periodically, until you call deactivate().
         * This method is automatically invoked by enabling my-location layer. */
        @Override
        public void activate(OnLocationChangedListener listener) {
            // We need to keep a reference to my-location layer's listener so we can Push forward
            // location updates to it when we receive them from Location Manager.
            mListener = listener;

            // Request location updates from Location Manager
            if (bestAvailableProvider != null) {
                locationManager.requestLocationUpdates(bestAvailableProvider, minTime, minDistance, this);
            } else {
                // (Display a message/dialog) No Location Providers currently available.
            }
        }

        /* Deactivates this provider.
         * This method is automatically invoked by disabling my-location layer. */
        @Override
        public void deactivate() {
            // Remove location updates from Location Manager
            locationManager.removeUpdates(this);

            mListener = null;
        }

        @Override
        public void onLocationChanged(Location location) {
            /* Push location updates to the registered listener..
             * (this ensures that my-location layer will set the blue dot at the new/received location) */
            if (mListener != null) {
                mListener.onLocationChanged(location);
            }

            /* ..and Animate camera to center on that location !
             * (the reason for we created this custom Location Source !) */
            mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(location.getLatitude(), location.getLongitude())));
        }

        @Override
        public void onStatusChanged(String s, int i, Bundle bundle) {

        }

        @Override
        public void onProviderEnabled(String s) {

        }

        @Override
        public void onProviderDisabled(String s) {

        }
    }

}
25
Nevermore
4
4ntoine

Ich bin auf das gleiche Problem gestoßen ... meine Lösung mittlerweile:

Erstellen Sie einen Thread, der einen Handler dazu auffordert, die Position einige Male zu ermitteln. Sie müssen einen Handler verwenden, da die getMyLocation-Methode nur vom GUI-Thread aufgerufen werden kann:

private class MyLocationThread extends Thread{
        @Override
        public void run() {
            int loops = 0;
            // we give the location search a minute 
            while(loops < 60){
                // we have to try it over a handler, because getMyLocation() has to be called from GUI Thread -_-
                _getMyLocationHandler.sendEmptyMessage(0);
                if(isInterrupted()){
                    return;
                }
                // take a short nap before next try
                try {Thread.sleep(1000);} catch(Exception e){}
                loops++;
            }

        }
    }

Der Handler macht folgendes:

private Handler _getMyLocationHandler = new Handler(){
        public void handleMessage(Android.os.Message msg) {
            if(getMap().isMyLocationEnabled() && getMap().getMyLocation() != null){
                _locationWatcher.interrupt();
                drawCurrentImagePositions();
            }
        }
    };
0
mAx