如何在Android Google地图视图中刷新标记？

Question

如何在Android地图上刷新标记位置（例如，当用户移动时）？我在locationManager.requestLocationUpdates中设置了3秒的刷新时间，但似乎它不起作用。

这是我的GPSTracker课程：

公共类GPSTracker extends Service实现LocationListener {

private final Context mContext;

// flag for GPS status
boolean isGPSEnabled = false;

// flag for network status
boolean isNetworkEnabled = false;

// flag for GPS status
boolean canGetLocation = false;

Location location; // location
double latitude; // latitude
double longitude; // longitude

// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 50; // 3 seconds

// Declaring a Location Manager
protected LocationManager locationManager;


public GPSTracker(Context context) {
    this.mContext = context;
    getLocation();
}

public Location getLocation() {
    try {
        locationManager = (LocationManager) mContext
                .getSystemService(LOCATION_SERVICE);

        // getting GPS status
        isGPSEnabled = locationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

        // getting network status
        isNetworkEnabled = locationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (!isGPSEnabled && !isNetworkEnabled) {
            // no network provider is enabled
        } else {
            this.canGetLocation = true;
            // First get location from Network Provider
            if (isNetworkEnabled) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (location != null) {
                        latitude = location.getLatitude();
                        longitude = location.getLongitude();
                    }
                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("GPS Enabled", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                        if (location != null) {
                            latitude = location.getLatitude();
                            longitude = location.getLongitude();
                        }
                    }
                }
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }

    return location;
}

 public void stopUsingGPS() {
    if (locationManager != null) {
        locationManager.removeUpdates(GPSTracker.this);
    }
}

public double getLatitude() {
    if (location != null) {
        latitude = location.getLatitude();
    }

    // return latitude
    return latitude;
}

public double getLongitude() {
    if (location != null) {
        longitude = location.getLongitude();
    }

    // return longitude
    return longitude;
}

public boolean canGetLocation() {
    return this.canGetLocation;
}

public void showSettingsAlert() {
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

    // Setting Dialog Title
    alertDialog.setTitle("GPS is settings");

    // Setting Dialog Message
    alertDialog
            .setMessage("GPS is not enabled. Do you want to go to settings menu?");

    // On pressing Settings button
    alertDialog.setPositiveButton("Settings",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    Intent intent = new Intent(
                            Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    mContext.startActivity(intent);
                }
            });

    // on pressing cancel button
    alertDialog.setNegativeButton("Cancel",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            });

    // Showing Alert Message
    alertDialog.show();
}

@Override
public void onLocationChanged(Location location) {
}

@Override
public void onProviderDisabled(String provider) {
}

@Override
public void onProviderEnabled(String provider) {
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}

@Override
public IBinder onBind(Intent arg0) {
    return null;
}

}

这是我的地图活动，我在其中创建地图并为其添加标记：

公共类MapsActivity扩展FragmentActivity实现OnMapReadyCallback {

private GoogleMap mMap;
private final static int REQUEST_CODE_ASK_PERMISSIONS = 1;
private static final String[] REQUIRED_SDK_PERMISSIONS = new String[]{
        Manifest.permission.ACCESS_FINE_LOCATION, 
        Manifest.permission.ACCESS_COARSE_LOCATION, 
        Manifest.permission.INTERNET, 
        Manifest.permission.ACCESS_NETWORK_STATE};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    checkPermissions();
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
}

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mapsCreate();
}

public void mapsCreate() {
    GPSTracker tracker = new GPSTracker(MapsActivity.this);
    double lat = tracker.getLatitude();
    double lng = tracker.getLongitude();
    // Add a marker for current location and move the camera
    LatLng currentLocation = new LatLng(lat, lng);
    mMap.addMarker(new MarkerOptions().position(currentLocation).title("Current Location Marker"));
    mMap.moveCamera(CameraUpdateFactory.newLatLng(currentLocation));
}

protected boolean checkPermissions() {
    final List<String> missingPermissions = new ArrayList<String>();
    // check all required dynamic permissions
    for (final String permission : REQUIRED_SDK_PERMISSIONS) {
        final int result = ContextCompat.checkSelfPermission(this, permission);
        if (result != PackageManager.PERMISSION_GRANTED) {
            missingPermissions.add(permission);
        }
    }
    if (!missingPermissions.isEmpty()) {
        // request all missing permissions
        final String[] permissions = missingPermissions
                .toArray(new String[missingPermissions.size()]);
        ActivityCompat.requestPermissions(this, permissions, REQUEST_CODE_ASK_PERMISSIONS);

    } else {
        final int[] grantResults = new int[REQUIRED_SDK_PERMISSIONS.length];
        Arrays.fill(grantResults, PackageManager.PERMISSION_GRANTED);
        onRequestPermissionsResult(REQUEST_CODE_ASK_PERMISSIONS, REQUIRED_SDK_PERMISSIONS,
                grantResults);
        return true;
    }
    return true;
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[],
                                       @NonNull int[] grantResults) {
    switch (requestCode) {
        case REQUEST_CODE_ASK_PERMISSIONS:
            for (int index = permissions.length - 1; index >= 0; --index) {
                if (grantResults[index] != PackageManager.PERMISSION_GRANTED) {
                    // exit the app if one permission is not granted
                    Toast.makeText(this, "Required permission '" + permissions[index]
                            + "' not granted, exiting", Toast.LENGTH_LONG).show();
                    finish();
                    return;
                }
            }
            // all permissions were granted
            break;
    }
}

任何帮助将非常感激！谢谢

Answer 1

添加到地图后保存标记对象。

myMarker = mMap.addMarker(new MarkerOptions().position(currentLocation).title("Current Location Marker"));

在位置更新后获取新位置回调更新标记的位置。

.....
myMarker.setPosition(newLatLng);