Question

我正在使用谷歌地图开发一个应用程序，我想在谷歌地图上向一个管理员显示多个用户位置。以下是仅显示用户当前位置的代码。现在请建议我如何在谷歌地图上显示多个用户位置？

//java activity
public class LocationActivity extends FragmentActivity implements
        com.google.android.gms.location.LocationListener,
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener {

    private static final String TAG = "LocationActivity";
    private static final long INTERVAL = 1000 * 60 * 1; //1 minute
    private static final long FASTEST_INTERVAL = 1000 * 60 * 1; // 1 minute

    private static final float SMALLEST_DISPLACEMENT = 0.25F; //quarter of a meter
    Button btnFusedLocation;
    TextView tvLocation;
    LocationRequest mLocationRequest;
    GoogleApiClient mGoogleApiClient;
    Location mCurrentLocation;
    String mLastUpdateTime;
    GoogleMap googleMap;

    private double longitude;
    private double latitude;
    private ArrayList<LatLng> points; //added
    Polyline line; //added

    protected void createLocationRequest() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(INTERVAL);
        mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
        mLocationRequest.setSmallestDisplacement(SMALLEST_DISPLACEMENT); //added
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    }
    /*
    protected void createLocationRequest() {
        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(INTERVAL);
        mLocationRequest.setFastestInterval(FASTEST_INTERVAL);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
    }  */

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d(TAG, "onCreate ...............................");

        points = new ArrayList<LatLng>();
        //show error dialog if GoolglePlayServices not available
        if (!isGooglePlayServicesAvailable()) {
            finish();
        }
        createLocationRequest();
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(LocationServices.API)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .build();

        setContentView(R.layout.activity_location_google_map);
        SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        googleMap = fm.getMap();
        googleMap.getUiSettings().setZoomControlsEnabled(true);

        if (getIntent().getExtras() != null) {
            final Bundle bundle = getIntent().getBundleExtra("LOCATION");
            latitude = bundle.getDouble("LATITUDE");
            longitude = bundle.getDouble("LONGITUDE");
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.d(TAG, "onStart fired ..............");
        mGoogleApiClient.connect();
    }

    @Override
    public void onStop() {
        super.onStop();
        Log.d(TAG, "onStop fired ..............");
        mGoogleApiClient.disconnect();
        Log.d(TAG, "isConnected ...............: " + mGoogleApiClient.isConnected());
    }

    private boolean isGooglePlayServicesAvailable() {
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
        if (ConnectionResult.SUCCESS == status) {
            return true;
        } else {
            GooglePlayServicesUtil.getErrorDialog(status, this, 0).show();
            return false;
        }
    }

    @Override
    public void onConnected(Bundle bundle) {
        Log.d(TAG, "onConnected - isConnected ...............: " + mGoogleApiClient.isConnected());
        startLocationUpdates();
    }

    protected void startLocationUpdates() {
        PendingResult<Status> pendingResult = LocationServices.FusedLocationApi.requestLocationUpdates(
                mGoogleApiClient, mLocationRequest, this);
        Log.d(TAG, "Location update started ..............: ");
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.d(TAG, "Connection failed: " + connectionResult.toString());
    }

    @Override
    public void onLocationChanged(Location location) {
        Log.d(TAG, "Firing onLocationChanged..............................................");
        mCurrentLocation = location;
        mLastUpdateTime = DateFormat.getTimeInstance().format(new Date());
        addMarker();

        longitude = location.getLongitude();
        latitude = location.getLatitude();
        LatLng latLng = new LatLng(latitude, longitude); //you already have this
        points.add(latLng); //added
        redrawLine();
    }

    private void addMarker() {
        MarkerOptions options = new MarkerOptions();

        // following four lines requires 'Google Maps Android API Utility Library'
        // https://developers.google.com/maps/documentation/android/utility/
        // I have used this to display the time as title for location markers
        // you can safely comment the following four lines but for this info
        IconGenerator iconFactory = new IconGenerator(this);
        iconFactory.setStyle(IconGenerator.STYLE_PURPLE);
        options.icon(BitmapDescriptorFactory.fromBitmap(iconFactory.makeIcon(mLastUpdateTime)));
        options.anchor(iconFactory.getAnchorU(), iconFactory.getAnchorV());

        LatLng currentLatLng = new LatLng(mCurrentLocation.getLatitude(), mCurrentLocation.getLongitude());
        options.position(currentLatLng);
        Marker mapMarker = googleMap.addMarker(options);
        long atTime = mCurrentLocation.getTime();
        mLastUpdateTime = DateFormat.getTimeInstance().format(new Date(atTime));
        mapMarker.setTitle(mLastUpdateTime);
        Log.d(TAG, "Marker added.............................");
        googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLatLng,
                13));
        Log.d(TAG, "Zoom done.............................");
    }

    @Override
    protected void onPause() {
        super.onPause();
        stopLocationUpdates();
    }

    protected void stopLocationUpdates() {
        LocationServices.FusedLocationApi.removeLocationUpdates(
                mGoogleApiClient, this);
        Log.d(TAG, "Location update stopped .......................");
    }

    @Override
    public void onResume() {
        super.onResume();
        if (mGoogleApiClient.isConnected()) {
            startLocationUpdates();
            Log.d(TAG, "Location update resumed .....................");
        }
    }

   // for map line
   private void redrawLine(){

       googleMap.clear();  //clears all Markers and Polylines
       PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
       for (int i = 0; i < points.size(); i++) {
           LatLng point = points.get(i);
           options.add(point);
       }
       addMarker(); //add Marker in current position
       line = googleMap.addPolyline(options); //add Polyline

   }
}

Answer 1

您可以添加与不同用户的位置相对应的多个标记。

如何在Android中的谷歌地图上显示多个用户的当前位置

1 个答案: