Affichage de la carte utilisateur suivant - fonctionnalité de type MyLocationOverlay pour Android Maps API v2
Je suis passé à la version 2 de Maps pour Android et j'essaie de transférer les fonctionnalités suivantes:
Avec MyLocationOverlay, je peux afficher la position actuelle des appareils (Blue Dot). Lorsque la position de l'utilisateur change et que le point atteint le bord de la zone visible, la carte s'anime de sorte que le point devienne le centre de la vue, en temps réel.
Dans la version 2, j'utilise SupportMapFragment avec getMap (). SetMyLocationEnabled (true). L'emplacement actuel apparaît sous la forme d'un point bleu (flèche), mais lorsque l'appareil change d'emplacement, la vue de la carte ne se décale pas et le point finit par quitter la vue.
Des idées?
UPDATE: Google a introduit le nouveau LocationClient et/ LocationListener associé (l'interface OnMyLocationChangeListener est maintenant obsolète). Alors maintenant, le centrage automatique de la caméra est une tâche triviale.
Bien que spotdog ait déjà répondu à la question, je souhaitais partager mon propre exemple. J'espère que cela aidera les débutants sur Android à mieux comprendre ce qu'il faut pour créer une variable LocationSource personnalisée pour la couche my-location. Espérons que vous constaterez que le code est bien documenté/commenté.
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) {
}
}
}
Vous devez ajouter un LocationSource à votre Google Map et répondre aux événements onLocationChanged. Voici une classe simple qui demande la position de l'utilisateur, puis attend que celle-ci soit disponible et anime la carte pour qu'elle soit centrée sur celle-ci.
public class MyLocationMapFragmentActivity extends FragmentActivity implements LocationListener, LocationSource
{
/**
* Note that this may be null if the Google Play services APK is not available.
*/
private GoogleMap mMap;
private OnLocationChangedListener mListener;
private LocationManager locationManager;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.basic_map);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if(locationManager != null)
{
boolean gpsIsEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
boolean networkIsEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if(gpsIsEnabled)
{
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000L, 10F, this);
}
else if(networkIsEnabled)
{
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 5000L, 10F, this);
}
else
{
//Show an error dialog that GPS is disabled.
}
}
else
{
//Show a generic error dialog since LocationManager is null for some reason
}
setUpMapIfNeeded();
}
@Override
public void onPause()
{
if(locationManager != null)
{
locationManager.removeUpdates(this);
}
super.onPause();
}
@Override
public void onResume()
{
super.onResume();
setUpMapIfNeeded();
if(locationManager != null)
{
mMap.setMyLocationEnabled(true);
}
}
/**
* 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
* call {@link #setUpMap()} once when {@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.
* <p>
* A user can return to this Activity after following the Prompt and correctly
* installing/updating/enabling the Google Play services. Since the Activity may not have been
* completely destroyed during this process (it is likely that it would only be stopped or
* paused), {@link #onCreate(Bundle)} may not be called again so we should call this method in
* {@link #onResume()} to guarantee that it will be called.
*/
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null)
{
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.basicMap)).getMap();
// Check if we were successful in obtaining the map.
if (mMap != null)
{
setUpMap();
}
//This is how you register the LocationSource
mMap.setLocationSource(this);
}
}
/**
* This is where we can add markers or lines, add listeners or move the camera. In this case, we
* just add a marker near Africa.
* <p>
* This should only be called once and when we are sure that {@link #mMap} is not null.
*/
private void setUpMap()
{
mMap.setMyLocationEnabled(true);
}
@Override
public void activate(OnLocationChangedListener listener)
{
mListener = listener;
}
@Override
public void deactivate()
{
mListener = null;
}
@Override
public void onLocationChanged(Location location)
{
if( mListener != null )
{
mListener.onLocationChanged( location );
//Move the camera to the user's location once it's available!
mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(location.getLatitude(), location.getLongitude())));
}
}
@Override
public void onProviderDisabled(String provider)
{
// TODO Auto-generated method stub
Toast.makeText(this, "provider disabled", Toast.LENGTH_SHORT).show();
}
@Override
public void onProviderEnabled(String provider)
{
// TODO Auto-generated method stub
Toast.makeText(this, "provider enabled", Toast.LENGTH_SHORT).show();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras)
{
// TODO Auto-generated method stub
Toast.makeText(this, "status changed", Toast.LENGTH_SHORT).show();
}
}
Cela devrait suivre l'utilisateur et continuer à centrer la carte sur son emplacement à mesure que cela change - si vous souhaitez centrer la carte sur l'utilisateur lorsqu'il passe en mode "Hors écran", vous pouvez alors vérifier si l'emplacement de l'utilisateur est à l'intérieur. les limites visibles de la carte
@Override
public void onLocationChanged(Location location)
{
if( mListener != null )
{
mListener.onLocationChanged( location );
LatLngBounds bounds = this.mMap.getProjection().getVisibleRegion().latLngBounds;
if(!bounds.contains(new LatLng(location.getLatitude(), location.getLongitude())))
{
//Move the camera to the user's location if they are off-screen!
mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(location.getLatitude(), location.getLongitude())));
}
}
}
Voici un bref exposé sur le sujet: API Google Maps Android V2 MyLocation LocationSource et gestion des événements
UPDATE
J'ai modifié la manière dont j'obtiens l'emplacement de l'utilisateur (voir le code de locationManager dans onCreate). J'ai constaté que les méthodes "getBestProvider" n'étaient pas fiables et ne fonctionnaient tout simplement pas sur plusieurs appareils. Plusieurs utilisateurs se sont plaints de ce que leurs appareils ne trouveraient jamais leur emplacement, peu importe le degré de relaxation des critères. Il semble que choisir manuellement le GPS ou le réseau fonctionne universellement.
Utilisez simplement OnMyLocationChangeListener, remplacez la méthode public void onMyLocationChange(Location location). Utilisez GoogleMap.setOnMyLocationChangeListener(your listener) pour enregistrer votre auditeur.
public void onMyLocationChange(Location location) {
changeMapLocation(location);
}
private void changeMapLocation(Location location) {
LatLng latlong = new LatLng(location.getLatitude(),
location.getLongitude());
map.moveCamera(CameraUpdateFactory.newLatLngZoom(latlong, 15));
// Zoom in, animating the camera.
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}