I want to find map of my current position and update it when i move via showing a icon in OSMdroid.I find no problem when give specific location latitude and longitude and drawing icon but there are two errors when i give current location latitude and longitude.
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
mResourceProxy = new DefaultResourceProxyImpl(getApplicationContext());
setContentView(R.layout.main);
mMapView = (MapView) this.findViewById(R.id.mapview);
mMapView.setTileSource(TileSourceFactory.MAPNIK);
mMapView.setBuiltInZoomControls(true);
mMapView.setMultiTouchControls(true);
mapController = this.mMapView.getController();
mapController.setZoom(15);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
criteria.setAltitudeRequired(false);
criteria.setBearingRequired(false);
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_LOW);
String provider = mLocMgr.getBestProvider(criteria, true);
Location location = mLocMgr.getLastKnownLocation(provider);
GeoPoint mypoint = new GeoPoint(location.getLatitude(), location.getLongitude()); // centre map here
GeoPoint mypointicon = new GeoPoint(location.getLatitude()+1000, location.getLongitude()+1000); // icon goes here
mapController.setCenter(mypoint);
mLocMgr = (LocationManager) getSystemService(LOCATION_SERVICE);
mLocMgr.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 100,
this);
ArrayList<OverlayItem> items=new ArrayList<OverlayItem>();
items.add(new OverlayItem("Here", "Sample Description", mypointicon));
this.mMyLocationOverlay = new ItemizedIconOverlay<OverlayItem>(items,
new ItemizedIconOverlay.OnItemGestureListener<OverlayItem>() {
#Override
public boolean onItemSingleTapUp(final int index,
final OverlayItem item) {
Toast.makeText(
MapOverLayGiveActivity.this,
"Item '" + item.mTitle, Toast.LENGTH_LONG).show();
return true; // We 'handled' this event.
}
#Override
public boolean onItemLongPress(final int index,
final OverlayItem item) {
Toast.makeText(
MapOverLayGiveActivity.this,
"Item '" + item.mTitle ,Toast.LENGTH_LONG).show();
return false;
}
}, mResourceProxy);
this.mMapView.getOverlays().add(this.mMyLocationOverlay);
mMapView.invalidate();
}
Error:
java.lang.NullPointerException
java.lang.RunTimeException
What's wrong in my code and how can i do that? thanks...
To follow location changes, implement LocationListener as below:
public class MyLocationListener implements LocationListener {
public void onLocationChanged(Location location) {
currentLocation = new GeoPoint(location);
displayMyCurrentLocationOverlay();
}
public void onProviderDisabled(String provider) {
}
public void onProviderEnabled(String provider) {
}
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
Inside onCreate method:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
locationListener = new MyLocationListener();
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if( location != null ) {
currentLocation = new GeoPoint(location.getLatitude(), location.getLongitude());
}
}
and displayMyCurrentLocationOverlay method:
private void displayMyCurrentLocationOverlay() {
if( currentLocation != null) {
if( currentLocationOverlay == null ) {
currentLocationOverlay = new ArrayItemizedOverlay(myLocationMarker);
myCurrentLocationOverlayItem = new OverlayItem(currentLocation, "My Location", "My Location!");
currentLocationOverlay.addItem(myCurrentLocationOverlayItem);
mapView.getOverlays().add(currentLocationOverlay);
} else {
myCurrentLocationOverlayItem.setPoint(currentLocation);
currentLocationOverlay.requestRedraw();
}
mapView.getController().setCenter(currentLocation);
}
}
You use this.myLocationOverlay - and because of that the osmDroid draw the current location - but for update the location you must use a location listener. Also, you must remove previous overlay from the map using mapView.getOverlays.clear() function
Well, let's say that you don't have acces to internet or GPS. In my opinion is safe to have a default point on the map.
In this code I check for a valid location. If is null, then I use DEFAULT values.
In my application I have no problems. I also draw a navigation path on the map, even if my location is changed.
{
Location location = null;
for (String provider : locationManager.getProviders(true))
{
location = locationManager.getLastKnownLocation(provider);
if (location != null)
{
//location.setLatitude(MAP_DEFAULT_LATITUDE);
//location.setLongitude(MAP_DEFAULT_LONGITUDE);
locationManager.requestLocationUpdates(provider, 0, 0, mUpdateHandler);
break;
}
}
//add car position
if (location == null)
{
location = new Location(LocationManager.GPS_PROVIDER);
location.setLatitude(MAP_DEFAULT_LATITUDE);
location.setLongitude(MAP_DEFAULT_LONGITUDE);
updateCarPosition(new GeoPoint(location));
}
}
if you test on Emulator then remember use DDMS to set your current lat & long. if you don't, the getLastKnownLocation will return null
Related
My android application function is to track the user location when it walk/run or when he never moves(then location should not change)First, the location is inaccurate and red marker keeps popping out on the map even if i never move. the position where it pops out is also inaccurate.
For those who did similar location tracking app before, the blue dot should be the same place as the latest red marker right? but my blue dot is always away most of the time. red marker shows a more accurate position(although still inaccurate)
i have tested it in my house, outside, in a vehicle. when it is in my house, sometimes location keeps changing, sometimes location never change. i cannot predict it. usually gps don't work well in-house so i leave it first
when i test it outside, sometimes it is better but it is still inaccurate. when i never move/move or move slow it update on the wrong location. althought it is sometimes little better then in roof. but in the end it is still unuseable.
when i test it in the car, it is better as it won't pop out so much location should be more accurate blue dot and red marker are sometimes together. although there are still inaccurate sometimes. but it does not matter as my app is supposed to use when the user is walking/running not in a moving vehicle.
for all three, red marker appears(no matter how frequently) around the correct environment(house, road, certain building) sometimes, but the blue dot is not, most of the times it is wrong. but i wanted the blue dot as a tracker for the user. user would not know which red marker is his current location even if it is accurate. the title "you are here" could appear on any marker when i tap on it, where it is new or old. so it is not effective. and when a new one appear, the title does not appear by itself.
the problem i am trying to solve is to ensure location accuracy, even if not good or perfect at lease be useable, and have the blue dot track the user continuously,or red marker as long as sometimes tell the where is he accurately(title only appears on the latest marker by itself).
i am research for a long time and i do not know what else i can implement to make it more accurate. the distance calculation i believe should be accurate but it depends on the location so it will becomes inaccurate too. sorry for the large text i just thought i should explain myself clearer...
public class MainActivity extends FragmentActivity implements LocationListener{
protected LocationManager locationManager;
private GoogleMap googleMap;
Button btnStartMove,btnPause,btnResume,btnStop;
static double n=0;
Long s1,r1;
double dis=0.0;
Thread t1;
EditText userNumberInput;
boolean bool=false;
int count=0;
double speed = 1.6;
double lat1,lon1,lat2,lon2,lat3,lon3,lat4,lon4;
double dist = 0.0;
double time = 0.0;
double velocity = 0.0;
TextView distance;
Button btnDuration;
float[] result;
private static final long MINIMUM_DISTANCE_CHANGE_FOR_UPDATES =1; // in Meters
private static final long MINIMUM_TIME_BETWEEN_UPDATES = 4000; //in milliseconds
boolean startDistance = false;
boolean startButtonClicked = false;
MyCount counter;
int timer = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,MINIMUM_TIME_BETWEEN_UPDATES,MINIMUM_DISTANCE_CHANGE_FOR_UPDATES, this);
if(isGooglePlay())
{
setUpMapIfNeeded();
}
distance=(TextView)findViewById(R.id.Distance);
btnDuration=(Button)findViewById(R.id.Duration);
btnStartMove=(Button)findViewById(R.id.Start);//start moving
btnStop=(Button)findViewById(R.id.Stop);
//prepare distance...........
Log.d("GPS Enabled", "GPS Enabled");
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
String provider = locationManager.getBestProvider(criteria, true);
Location location=locationManager.getLastKnownLocation(provider);
btnStartMove.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
Log.d("GPS Enabled", "GPS Enabled");
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
String provider = locationManager.getBestProvider(criteria, true);
Location location=locationManager.getLastKnownLocation(provider);
lat3 = location.getLatitude();
lon3 = location.getLongitude();
startButtonClicked=true;
startDistance=true;
counter= new MyCount(30000,1000);
counter.start();
btnStartMove.setText("Started...");
}
});
btnStop.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
startButtonClicked=false;
startDistance=false;
//Double.valueOf(distance.getText().toString()
Double value=dist;
Double durationValue=time;
Double speedValue=velocity;
Intent intent = new Intent(MainActivity.this, FinishActivity.class);
intent.putExtra("dist", value);
intent.putExtra("time",durationValue);
intent.putExtra("velocity",speedValue);
startActivity(intent);
counter.cancel();
n=0;
r1=null;
time=0.0;
btnStartMove.setText("Start Move");
finish();
}
});
btnDuration.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v) {
if(startButtonClicked=true)
{
time=n*30+r1;
velocity=dist/time;
DecimalFormat df = new DecimalFormat("#.##");
Toast.makeText(MainActivity.this,"Duration :"+String.valueOf(time) + "Speed :"+String.valueOf(df.format(velocity)),Toast.LENGTH_LONG).show();
}
}
});
if(location!= null)
{
//Display current location in Toast
String message = String.format(
"Current Location \n Longitude: %1$s \n Latitude: %2$s",
location.getLongitude(), location.getLatitude()
);
Toast.makeText(MainActivity.this, message,
Toast.LENGTH_LONG).show();
}
else if(location == null)
{
Toast.makeText(MainActivity.this,
"Location is null",
Toast.LENGTH_LONG).show();
}
}
private void setUpMapIfNeeded() {
if(googleMap == null)
{
googleMap =((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.displayMap)).getMap();
if(googleMap != null)
{
setUpMap();
}
}
}
private void setUpMap()
{
//Enable MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
//Get locationManager object from System Service LOCATION_SERVICE
//LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
//Create a criteria object to retrieve provider
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
//Get the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
if(provider == null)
{
onProviderDisabled(provider);
}
//set map type
googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
//Get current location
Location myLocation = locationManager.getLastKnownLocation(provider);
if(myLocation != null)
{
double latitude = myLocation.getLatitude();
//Get longitude of the current location
double longitude = myLocation.getLongitude();
//Create a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
//Show the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
//Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(20));
googleMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).snippet("You are here!").title("You are here!"));
}
locationManager.requestLocationUpdates(provider, 0, 0, this);
}
private boolean isGooglePlay()
{
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (status == ConnectionResult.SUCCESS)
{
Toast.makeText(MainActivity.this, "Google Play Services is available",
Toast.LENGTH_LONG).show();
return(true);
}
else
{
GooglePlayServicesUtil.getErrorDialog(status, this, 10).show();
}
return (false);
}
#Override
public void onLocationChanged(Location myLocation) {
System.out.println("speed " + myLocation.getSpeed());
//show location on map.................
//Get latitude of the current location
double latitude = myLocation.getLatitude();
//Get longitude of the current location
double longitude = myLocation.getLongitude();
//Create a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
//Show the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
//Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(20));
googleMap.addMarker(new MarkerOptions().position(new LatLng(latitude, longitude)).snippet("You are here!").title("You are here!"));
//show distance............................
if(startDistance == true)
{
Toast.makeText(MainActivity.this,
"Location has changed",
Toast.LENGTH_LONG).show();
if(myLocation != null)
{
//latitude.setText("Current Latitude: " + String.valueOf(loc2.getLatitude()));
//longitude.setText("Current Longitude: " + String.valueOf(loc2.getLongitude()));
float[] results = new float[1];
Location.distanceBetween(lat3, lon3, myLocation.getLatitude(), myLocation.getLongitude(), results);
System.out.println("Distance is: " + results[0]);
dist += results[0];
DecimalFormat df = new DecimalFormat("#.##"); // adjust this as appropriate
if(count==1)
{
distance.setText(df.format(dist) + "meters");
}
lat3=myLocation.getLatitude();
lon3=myLocation.getLongitude();
count=1;
}
}
if(startButtonClicked == true)
{
startDistance=true;
}
}
#Override
public void onProviderDisabled(String provider) {
Toast.makeText(MainActivity.this,
"Provider disabled by the user. GPS turned off",
Toast.LENGTH_LONG).show();
}
#Override
public void onProviderEnabled(String provider) {
Toast.makeText(MainActivity.this,
"Provider enabled by the user. GPS turned on",
Toast.LENGTH_LONG).show();
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
Toast.makeText(MainActivity.this, "Provider status changed",
Toast.LENGTH_LONG).show();
}
#Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
#Override
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,MINIMUM_TIME_BETWEEN_UPDATES,MINIMUM_DISTANCE_CHANGE_FOR_UPDATES, this);
}
public class MyCount extends CountDownTimer{
public MyCount(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
}
#Override
public void onFinish() {
counter= new MyCount(30000,1000);
counter.start();
n=n+1;
}
#Override
public void onTick(long millisUntilFinished) {
s1=millisUntilFinished;
r1=(30000-s1)/1000;
}
}}
I am writing a code in order to be able to use localisation (GPS based if available else Network based). Everything works fine if I enter my activity with GPS turned ON on my mobile.
But if i enter the Activity with GPS turned off and then i enable GPS while in the Activity nothing happens and NETWORK based location is still active instead of switching to GPS based.
Did i miss something ?
Thanks
public class MapActivity extends Activity implements LocationListener {
//Used CameraPosition attributes
private final int MAP_BEARING = 69;
private final int SETUP_ZOOM = 16;
private final int AT_POSITION_ZOOM = 19;
private final int UPDATE_FREQUENCY = 20000; //Update frequency (ms)
private final LatLng MAP_CENTER = new LatLng(44.80736, -0.596572);
private CheckBox mServices, mRestauration, mBuildings;
private Resources mResources;
private GoogleMap mMap;
private LocationManager mLocationManager;
private Marker mCurrentLocation;
private ArrayList<Marker> mServicesMarkers, mRestaurationMarkers, mBuildingsMarkers;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
mResources = getResources();
mServices = (CheckBox) findViewById(R.id.services_check);
mRestauration = (CheckBox) findViewById(R.id.restauration_check);
mBuildings = (CheckBox) findViewById(R.id.buildings_check);
setUpLocationServices();
}
public void setUpLocationServices() {
mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_FINE);
String provider = mLocationManager.getBestProvider(criteria, true);
Location location = mLocationManager.getLastKnownLocation(provider);
double latitude = location.getLatitude();
double longitude = location.getLongitude();
LatLng currentPosition = new LatLng(latitude, longitude);
mCurrentLocation = mMap.addMarker(new MarkerOptions()
.position(currentPosition)
.title("Votre position")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.user_location_marker)));
if (location != null)
onLocationChanged(location);
if (isGpsEnabled())
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
else
mLocationManager.requestLocationUpdates(provider, UPDATE_FREQUENCY, 0, this);
}
#Override
public void onLocationChanged(Location location) {
mCurrentLocation.remove();
LatLng currentPosition = new LatLng(location.getLatitude(), location.getLongitude());
mCurrentLocation = mMap.addMarker(new MarkerOptions()
.position(currentPosition)
.title("Votre position")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.user_location_marker)));
}
public boolean isGpsEnabled() {
LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
return service.isProviderEnabled(LocationManager.GPS_PROVIDER);
}
#Override
public void onProviderDisabled(String provider) {
mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if (isGpsEnabled())
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
else
mLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, UPDATE_FREQUENCY, 0, this);
}
#Override
public void onProviderEnabled(String provider) {
mLocationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
if (isGpsEnabled())
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
else
mLocationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, UPDATE_FREQUENCY, 0, this);
}
#Override
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
}
The problem seems to be here:
if (isGpsEnabled())
mLocationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
else
mLocationManager.requestLocationUpdates(provider, UPDATE_FREQUENCY, 0, this);
You run this code only once, in onCreate(). If you want location updates once the GPS has been enabled, you need to ask for it. On modern devices, I prefer to use Google's Play Service Location API with a Fused Location provider. This is how I implemented in my last commercial application, falling back to GPS only if Google Play wasn't installed.
Another option, if you look at this link, at the isBetterLocation method, you can compare your current value to the new one, and choose the better of the two. That way, if you have one and get the other, you can decide whether it's a better location than you had previously.
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.
Closed 10 years ago.
In this my code i did not understand where i did mistake in my code .I did not get current location on map view with pin point image. How to get the Latitude & Latitude and pass in Geo point. then pass the value OverlayItem ..
public class HelloGoogleMaps2 extends MapActivity implements LocationListener{
private LocationManager locationManager;
private String provider;
int lat;
int lng;
MyLocationOverlay myLocOverlay;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MapView mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
// Get the location manager
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
// Define the criteria how to select the locatioin provider -> use
// default
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, true);
Location location = locationManager.getLastKnownLocation(provider);
Log.d("provider ","Provider "+provider);
Log.d("provider ","Provider "+provider);
Log.d("provider ","Provider "+provider);
Log.d("location","Location "+location);
Log.d("location","Location "+location);
Log.d("location","Location "+location);
// Initialize the location fields
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
onLocationChanged(location);
} else {
//latituteField.setText("Location not available");
// longitudeField.setText("Location not available");
}
List<Overlay> mapOverlays = mapView.getOverlays();
myLocOverlay = new MyLocationOverlay(this, mapView);
mapOverlays.add(myLocOverlay);
myLocOverlay.enableMyLocation();
GeoPoint point = new GeoPoint(lat, lng);
// mc.setCenter(point);
// mapView.invalidate();
Drawable drawable = this.getResources().getDrawable(R.drawable.ic_launcher);
HelloItemizedOverlay itemizedoverlay = new HelloItemizedOverlay(drawable);
GeoPoint point = new GeoPoint(lat,lng);
OverlayItem overlayitem = new OverlayItem(point, "Hola, Mundo!", "I'm in Mexico City!");
itemizedoverlay.addOverlay(overlayitem);
mapOverlays.add(itemizedoverlay);
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
/* Remove the locationlistener updates when Activity is paused */
//
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
//
public void onLocationChanged(Location location) {
lat = (int) (location.getLatitude()* 1E6);
lng = (int) (location.getLongitude()* 1E6);
// latituteField.setText(String.valueOf(lat));
// longitudeField.setText(String.valueOf(lng));
}
//
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
//
public void onProviderEnabled(String provider) {
Toast.makeText(this, "Enabled new provider " + provider,
Toast.LENGTH_SHORT).show();
}
//
public void onProviderDisabled(String provider) {
Toast.makeText(this, "Disabled provider " + provider,
Toast.LENGTH_SHORT).show();
}
}
The right code is this ,but also add uses-permissio ,Internet,ACCESS_COARSE_LOCATION,ACCESS_FINE_LOCATION and WRITE_EXTERNAL_STORAGE .user-library .
public class GoogleMapActivity extends MapActivity implements LocationListener {
private final static String TAG = GoogleMapActivity.class.getSimpleName();
private MyItemizedOverlay itemizedOverlay;
double lat;
double lng;
private String provider;
private LocationManager locationManager;
private MapView mapview;
Drawable drawable;
boolean sat = true;
boolean dra = true;
private MapController controller;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// fetch the map view from the layout
mapview = (MapView) findViewById(R.id.mapview);
// make available zoom controls
mapview.setBuiltInZoomControls(false);
// Use the location manager through GPS
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
System.out.println("Provider " + provider + " has been selected.");
lat = (double) (location.getLatitude());
lng = (double) (location.getLongitude());
Log.i(TAG, "Lattitude:" + lat);
Log.i(TAG, "Longitude:" + lng);
Toast.makeText(
this,
"Current location:\nLatitude: " + lat + "\n"
+ "Longitude: " + lng, Toast.LENGTH_LONG).show();
// create geo point
GeoPoint point = new GeoPoint((int) (lat * 1E6), (int) (lng * 1E6));
// get the MapController object
controller = mapview.getController();
// animate to the desired point
controller.animateTo(point);
// set the map zoom to 13
// zoom 1 is top world view
controller.setZoom(13);
// invalidate the map in order to show changes
mapview.invalidate();
drawable = this.getResources().getDrawable(R.drawable.ic_launcher);
OverlayItem overlayItem = new OverlayItem(point, "", "");
itemizedOverlay = new MyItemizedOverlay(drawable, this);
itemizedOverlay.addOverlay(overlayItem);
mapview.getOverlays().add(itemizedOverlay);
mapview.invalidate();
} else {
System.out.println("Location not avilable");
}
// when the current location is found – stop listening for updates
// (preserves battery)
locationManager.removeUpdates(this);
}
#Override
protected boolean isRouteDisplayed() {
return false;
}
#Override
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
/* Remove the locationlistener updates when Activity is paused */
#Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
public void onProviderDisabled(String provider) {
Toast.makeText(this, "Disabled provider " + provider,
Toast.LENGTH_SHORT).show();
}
public void onProviderEnabled(String provider) {
Toast.makeText(this, "Enabled new provider " + provider,
Toast.LENGTH_SHORT).show();
}
public void onStatusChanged(String provider, int status, Bundle extras) {
}
public void onLocationChanged(Location location) {
}
public MapView getMapView() {
return this.mapview;
}
}
` //here is another of item overlay
public class MyItemizedOverlay extends ItemizedOverlay<OverlayItem>
{
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>();
public MyItemizedOverlay(Drawable defaultMarker, Context ctx){
super(boundCenterBottom(defaultMarker));
}
public void addOverlay(OverlayItem overlay) {
mOverlays.add(overlay);
populate();
}
public void clear() {
mOverlays.clear();
populate();
}
#Override
protected OverlayItem createItem(int i) {
return mOverlays.get(i);
}
#Override
public int size() {
return mOverlays.size();
}
#Override
protected boolean onTap(int index) {
return true;
}
}
I would recommend MyLocationOverlay.
An Overlay for drawing the user's current location (and accuracy) on the map, and/or a compass-rose inset. Subclases can override dispatchTap() to handle taps on the current location.
You will want to call enableMyLocation() and/or enableCompass(), probably from your Activity's Activity.onResume() method, to enable the features of this overlay. Remember to call the corresponding disableMyLocation() and/or disableCompass() in your Activity's Activity.onPause() method to turn off updates when in the background.
Optionally, the constructor can also take a MapController and use it to keep the "my location" dot visible by panning the map when it would go offscreen, and a View to View.postInvalidate() when location or orientation is changed.
Runnables can be provided in runOnFirstFix(java.lang.Runnable) to be run as soon as we have a fix. (For example, this could center the map and zoom in to show the location.)
You can find a good tutorial on MyLocationOverlay here
I am trying to find my current location for an android project. When the application is loaded my current location is always null. I have set up the permissions in the manifest etc. When I find the current location I intend to use the coordinates to find distances to other locations on the map. My code snippet is below. Why do I always get a null value?
locMan = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria crit = new Criteria();
towers = locMan.getBestProvider(crit, false);
location = locMan.getLastKnownLocation(towers);
if (location != null) {
System.out.println("Location is not null!");
lat = (int) (location.getLatitude() *1E6);
longi = (int) (location.getLongitude() * 1E6);
GeoPoint ourLocation = new GeoPoint(lati, longi);
OverlayItem overlayItem = new OverlayItem(ourLocation, "1st String",
"2nd String");
CustomPinpoint custom = new CustomPinpoint(d, MainMap.this);
custom.insertPinpoint(overlayItem);
overlayList.add(custom);
overlayList.clear();
} else {
System.out.println("Location is null! " + towers);
Toast.makeText(MainMap.this, "Couldn't get provider",Toast.LENGTH_SHORT)
.show();
}
getLastKnownLocation() uses the location(s) previously found by other applications. if no application has done this, then getLastKnownLocation() will return null.
One thing you can do to your code to have a better chance at getting as last known location- iterate over all of the enabled providers, not just the best provider. For example,
private Location getLastKnownLocation() {
List<String> providers = mLocationManager.getProviders(true);
Location bestLocation = null;
for (String provider : providers) {
Location l = mLocationManager.getLastKnownLocation(provider);
ALog.d("last known location, provider: %s, location: %s", provider,
l);
if (l == null) {
continue;
}
if (bestLocation == null
|| l.getAccuracy() < bestLocation.getAccuracy()) {
ALog.d("found best last known location: %s", l);
bestLocation = l;
}
}
if (bestLocation == null) {
return null;
}
return bestLocation;
}
If your app can't deal without having a location, and if there's no last known location, you will need to listen for location updates. You can take a look at this class for an example,
https://github.com/farble1670/autobright/blob/master/src/org/jtb/autobright/EventService.java
See the method onStartCommand(), where it checks if the network provider is enabled. If not, it uses last known location. If it is enabled, it registers to receive location updates.
if u find current location of devices the use following method in main class
public void find_Location(Context con) {
Log.d("Find Location", "in find_location");
this.con = con;
String location_context = Context.LOCATION_SERVICE;
locationManager = (LocationManager) con.getSystemService(location_context);
List<String> providers = locationManager.getProviders(true);
for (String provider : providers) {
locationManager.requestLocationUpdates(provider, 1000, 0,
new LocationListener() {
public void onLocationChanged(Location location) {}
public void onProviderDisabled(String provider) {}
public void onProviderEnabled(String provider) {}
public void onStatusChanged(String provider, int status,
Bundle extras) {}
});
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
addr = ConvertPointToLocation(latitude, longitude);
String temp_c = SendToUrl(addr);
}
}
}
And Add User Permission method in your manifest file
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
Try this this will not give you null current location
class GetLastLocation extends TimerTask {
LocationManager mlocManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);
LocationListener mlocListenerTmp = new CustomLocationListener();
private final Handler mLocHandler;
public GetLastLocation(Handler mLocHandler) {
this.mLocHandler = mLocHandler;
}
#Override
public void run() {
timer.cancel();
mlocManager.removeUpdates(mlocListenerTmp);
Location location = mlocManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
{
if (mlocListenerTmp != null) {
mlocManager.removeUpdates(mlocListenerTmp);
}
currentLocation = location;
}
if (location != null) {
String message = String.format(
"Location \n Longitude: %1$s \n Latitude: %2$s",
location.getLongitude(), location.getLatitude());
Log.d("loc", " :" + message);
Bundle b = new Bundle();
{
b.putBoolean("locationRetrieved", true);
{
Message msg = Message.obtain();
{
msg.setData(b);
mLocHandler.sendMessage(msg);
}
}
}
} else {
Log.d(
"loc",
":No GPS or network signal please fill the location manually!");
location = mlocManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
currentLocation = location;
Bundle b = new Bundle();
{
b.putBoolean("locationRetrieved", true);
{
Message msg = Message.obtain();
{
msg.setData(b);
mLocHandler.sendMessage(msg);
}
}
}
} else {
Bundle b = new Bundle();
{
b.putBoolean("locationRetrieved", false);
{
Message msg = Message.obtain();
{
msg.setData(b);
mLocHandler.sendMessage(msg);
}
}
}
}
}
}
}
call it like this
timer.schedule(new GetLastLocation(mLocHandler), 3000);
and the customLocationclass is as follows
public class CustomLocationListener implements LocationListener {
#Override
public void onLocationChanged(Location loc) {
loc.getLatitude();
loc.getLongitude();
currentLocation = loc;
String Text = "My current location is: " + "Latitud = "
+ loc.getLatitude() + "Longitud = " + loc.getLongitude();
Log.d("loc", "onLocationChanged" + Text);
}
#Override
public void onProviderDisabled(String provider) {}
#Override
public void onProviderEnabled(String provider) {}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {}
}
If you are trying it out in a marshmallow device, try enabling location permission for your app manually.
turn on your GPS by using below method. it helps you to show your current location without any ERROR. call it in onCreate
public void displayLocationSettingsRequest(Context context, int requestCode) {
GoogleApiClient googleApiClient = new GoogleApiClient.Builder(context)
.addApi(LocationServices.API).build();
googleApiClient.connect();
LocationRequest locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(10000);
locationRequest.setFastestInterval(10000 / 2);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder().addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
PendingResult<LocationSettingsResult> result = LocationServices.SettingsApi.checkLocationSettings(googleApiClient, builder.build());
result.setResultCallback(result1 -> {
final Status status = result1.getStatus();
if (status.getStatusCode() == LocationSettingsStatusCodes.RESOLUTION_REQUIRED)
try {
status.startResolutionForResult((Activity) context, requestCode);
} catch (IntentSender.SendIntentException ignored) {
}
});
If you are getting a null error with your provider list, change...
List<String> providers = mLocationManager.getProviders(true);
to...
List<String> providers = locationManager.getAllProviders();
This worked for me, and make sure that you have the following in your AndroidManifest.xml file...
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
Have you tried reversing the code? For example, if(location==null) then print that location is null, and else print location is not null. I got that problem once before and that seemed to have fixed it (i don't know why). Try that.
If that doesn't work, perhaps the google maps API is returning the null value, in which case its a problem with the GM-API or with the call method. Any of these could be the problem.
I have a problem with obtaining the current user location. Code at first works but after some time it just stops showing the current location. I tried several approaches to this problem but with the same result.
Here's my code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mapscreen);
mapView = (MapView) findViewById(R.id.mapView);
mapController = mapView.getController();
String provider = getProvider();
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
//getLastKnownPoint();
locationManager.requestLocationUpdates(provider, 0, 0, locationListener);
drawCurrPositionOverlay();
}
private LocationListener locationListener = new LocationListener() {
#Override
public void onLocationChanged(Location location) {
GeoPoint currentPoint = getCurrentPoint(location);
animateToCurrentPoint(currentPoint);
currentLocation = location;
currentGeoPoint = currentPoint;
}
#Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
#Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
#Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
};
public GeoPoint getCurrentPoint (Location location){
GeoPoint currentPoint = new GeoPoint((int)(location.getLatitude()*1E6),(int)(location.getLongitude()*1E6));
return currentPoint;
}
public GeoPoint getLastKnownPoint (){
GeoPoint lastKnownPoint = null;
Location lastKnownLocation = locationManager.getLastKnownLocation(getProvider());
if(lastKnownLocation != null){
lastKnownPoint = getCurrentPoint(lastKnownLocation);
}
return lastKnownPoint;
}
public void animateToCurrentPoint(GeoPoint currentPoint){
mapController.animateTo(currentPoint);
mapController.setCenter(currentPoint);
mapController.setZoom(15);
}
public void drawCurrPositionOverlay(){
List<Overlay> overlays = mapView.getOverlays();
CustomItemizedOverlay<CustomOverlayItem> itemizedOverlay;
overlays.remove(currPos);
Drawable marker = getResources().getDrawable(R.drawable.me);
currPos = new MapOverlay(marker,mapView);
GeoPoint drawMyPoint = null;
if(currentGeoPoint==null){
drawMyPoint = getLastKnownPoint();
}
else {
drawMyPoint = currentGeoPoint;
}
OverlayItem overlayitem = new OverlayItem(drawMyPoint, "I'm here ", "wee");
currPos.addOverlay(overlayitem);
overlays.add(currPos);
currPos.setCurrentLocation(currentLocation);
}
public String getProvider() {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setPowerRequirement(Criteria.NO_REQUIREMENT);
criteria.setAccuracy(Criteria.NO_REQUIREMENT);
String Provider = locationManager.getBestProvider(criteria, true);
return Provider;
}
#Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
#Override
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(getProvider(), 100, 1, locationListener);
}
#Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(locationListener);
}
}
And I also had a problem with the drawCurrPosition (when code "was working") function (which uses custom balloons), method put a marker on the last known location, not on my current location (so marker was always one step back).
Function put the marker on the current location only on the opening app.
Please can you help me as I can't see what's wrong with my code
drawCurrPositionOverlay() is called in onCreate() and should really just be called in the onLocationChanged(). That way your overlay is always being updated with the current location instead of containing just the first location.