How do I move marker on Google maps api V2 ? I am using below code but it does not move marker on the map. What am I doing wrong here ? This should work when location changes, so I have added onLocationChanged method and in that, am getting location details and trying to move marker on new details, but this doesn't work.
Here is my code:
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.gson.Gson;
public class MapViewActivity extends Activity implements LocationListener,
SensorEventListener, OnClickListener {
GoogleMap googleMap;
private boolean started = false;
private ArrayList<AccelLocData> sensorData;
private SensorManager sensorManager;
private Button btnStart, btnStop;
private String provider;
// File root, dir, sensorFile;
FileOutputStream fOut;
private Sensor mAccelerometer;
private FileWriter writer;
private DatabaseHelper databaseHelper;
private BroadcastReceiver alarmReceiver;
private PendingIntent pendingIntentSender, pendingIntentReceiver;
private AlarmManager alarmManager;
private Intent alarmIntent,alarmIntent2;
// private Button btnUpload;
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
databaseHelper = new DatabaseHelper(this);
databaseHelper.removeAll();
Log.v("datacount",
Integer.toString(databaseHelper.getLocDataCount()));
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = sensorManager
.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
btnStart = (Button) findViewById(R.id.btnStart);
btnStop = (Button) findViewById(R.id.btnStop);
btnStart.setOnClickListener(this);
btnStop.setOnClickListener(this);
btnStart.setEnabled(true);
btnStop.setEnabled(false);
alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
int status = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(getBaseContext());
if (status != ConnectionResult.SUCCESS) { // Google Play Services
// are
// not available
int requestCode = 10;
Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status,
this, requestCode);
dialog.show();
} else { // Google Play Services are available
// Getting reference to the SupportMapFragment of
// activity_main.xml
// SupportMapFragment supportMapFragment = (MapFragment)
// getFragmentManager().findFragmentById(R.id.map);
// Getting GoogleMap object from the fragment
googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
// can use for overlay on the map
List<Double> latList = new ArrayList<Double>();
latList.add(145.7309593);
latList.add(146.34);
latList.add(147.34);
List<Double> lonList = new ArrayList<Double>();
lonList.add(-122.6365384);
lonList.add(-123.6365384);
lonList.add(-124.6365384);
for (int i = 0; i < 3; i++) {
// LatLng latLng = new LatLng(45.7309593, -122.6365384);
LatLng latLng = new LatLng(latList.get(i).doubleValue(),
lonList.get(i).doubleValue());
googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
googleMap
.addMarker(new MarkerOptions()
.position(latLng)
.title("My Spot")
.snippet("This is my spot!")
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
}
// Enabling MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, true);
Location location = locationManager
.getLastKnownLocation(provider);
if (location != null) {
onLocationChanged(location);
}
locationManager
.requestLocationUpdates(provider, 20000, 0, this);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void onSensorChanged(SensorEvent event) {
if (started) {
double x = event.values[0];
double y = event.values[1];
double z = event.values[2];
long timestamp = System.currentTimeMillis();
LocationManager locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setPowerRequirement(Criteria.POWER_MEDIUM);
criteria.setAccuracy(Criteria.ACCURACY_FINE);
provider = locManager.getBestProvider(criteria, true);
Location location = locManager.getLastKnownLocation(provider);
double latitude = 0;
double longitude = 0;
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
AccelLocData accelLocData = new AccelLocData(timestamp, x, y, z,
latitude, longitude);
// Log.d("X data","data x:" + data.getX());
try {
// writer.write(data.toString());
if (databaseHelper != null)
databaseHelper.insertLocData(accelLocData);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Override
public void onLocationChanged(Location location) {
TextView tvLocation = (TextView) findViewById(R.id.tv_location);
// Getting latitude of the current location
double latitude = location.getLatitude();
// Getting longitude of the current location
double longitude = location.getLongitude();
// Creating a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
// Showing the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnStart:
Context context = getApplicationContext();
alarmIntent = new Intent(context, AccelLocSender.class);
AlarmManager alarmManager = (AlarmManager) context
.getSystemService(Context.ALARM_SERVICE);
pendingIntentSender = PendingIntent.getBroadcast(context, 0,
alarmIntent, 0);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
System.currentTimeMillis(), 60000, pendingIntentSender);
alarmIntent2 = new Intent(context, AccelLocReceiver.class);
pendingIntentReceiver = PendingIntent.getBroadcast(context, 0,
alarmIntent2, 0);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
System.currentTimeMillis(), 30000, pendingIntentReceiver);
btnStart.setEnabled(false);
btnStop.setEnabled(true);
Log.d("startbutton", "cam on click of start");
started = true;
// delete all files..
// start thread to send data
sensorManager.registerListener(this, mAccelerometer,
SensorManager.SENSOR_DELAY_FASTEST);
break;
case R.id.btnStop:
try {
btnStart.setEnabled(true);
btnStop.setEnabled(false);
// btnUpload.setEnabled(true);
started = false;
sensorManager.unregisterListener(this);
Context context1 = getApplicationContext();
AlarmManager alarmManager1 = (AlarmManager) context1
.getSystemService(Context.ALARM_SERVICE);
alarmManager1.cancel(pendingIntentSender);
alarmManager1.cancel(pendingIntentReceiver);
// System.exit(0);
} catch (Exception e) {
e.printStackTrace();
}
break;
default:
break;
}
}
protected void onPause() {
super.onPause();
/*
* if (writer != null) { try { writer.close(); } catch (IOException e) {
* // TODO Auto-generated catch block e.printStackTrace(); } }
*/
}
protected void onResume() {
super.onResume();
/*
* try { Log.d("onresume","called onresume"); writer = new
* FileWriter(sensorFile, true); } catch (IOException e) { // TODO
* Auto-generated catch block e.printStackTrace(); }
*/
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
}
JRowan
Make variable
Marker now;
in this part add Marker and remove marker, of course put in the rest of your marker attributes:
@Override
public void onLocationChanged(Location location) {
if(now != null){
now.remove();
}
TextView tvLocation = (TextView) findViewById(R.id.tv_location);
// Getting latitude of the current location
double latitude = location.getLatitude();
// Getting longitude of the current location
double longitude = location.getLongitude();
// Creating a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
now = googleMap.addMarker(new MarkerOptions().position(latLng)));
// Showing the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
}
Make the marker draggable using,
MarkerOptions markerOptions = new MarkerOptions().position(myLaLn).title(
"Current Location").draggable(true);
map.addMarker(markerOptions);
& Get the dragged position & details as follows,
map.setOnMarkerDragListener(new GoogleMap.OnMarkerDragListener() {
@Override
public void onMarkerDragStart(Marker marker) {
}
@Override
public void onMarkerDragEnd(Marker marker) {
Log.d(TAG, "latitude : "+ marker.getPosition().latitude);
marker.setSnippet(marker.getPosition().latitude);
map.animateCamera(CameraUpdateFactory.newLatLng(marker.getPosition()));
}
@Override
public void onMarkerDrag(Marker marker) {
}
});
Optimized way to move marker :
marker mMarker;
After adding marker to map. while change the location you just need to set position rather than remove marker and add again.
mMarker.setPosition(new LatLon(latLng));
this will reduce the code from remove and add marker to direct set position and also reduce complexity. :)
Enjoy.
You are just moving camera on location change where as you should add marker as well then it will draw marker on current location. and before adding marker clear all the previous markers by calling googlmap.clear();
addMarker returns a reference to the marker which then later can be updated
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
@Override
public void onMapClick(LatLng latLng) {
if(mMarker == null) {
mMarker = mMap.addMarker(new MarkerOptions().position(latLng));
} else {
mMarker.setPosition(latLng);
}
}
});
来源：https://stackoverflow.com/questions/16312754/move-marker-on-google-maps-api-2