Finding a Location on Google Map
I am trying to find my location on Google Map. My code is here. I started the app on my phone, but unfortunately it stopped. Any ideas on what might be the problem? Thank.
public class MainActivity extends Activity implements LocationListener {
private LatLng loc ;
private LocationManager locationManager;
private String provider;
@SuppressLint("NewApi")
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
onLocationChanged(location);
}
GoogleMap map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
map.addMarker(new MarkerOptions().position(loc).title("Istanbul"));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(loc, 15));
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}
@Override
public void onLocationChanged(Location location) {
double lat = (double) (location.getLatitude());
double lng = (double) (location.getLongitude());
loc = new LatLng(lat,lng);
}
@Override
public void onProviderDisabled(String provider) {
// 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
protected void onResume() {
super.onResume();
locationManager.requestLocationUpdates(provider, 400, 1, this);
}
@Override
protected void onPause() {
super.onPause();
locationManager.removeUpdates(this);
}
}
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3 answers
public class MainActivity extends FragmentActivity implements LocationListener {
GoogleMap googleMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Getting Google Play availability status
int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());
// Showing status
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 fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
// Getting GoogleMap object from the fragment
googleMap = fm.getMap();
// Enabling MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
// Getting LocationManager object from System Service LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location
Location location = locationManager.getLastKnownLocation(provider);
if(location!=null){
onLocationChanged(location);
}
locationManager.requestLocationUpdates(provider, 20000, 0, this);
}
}
@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));
// Setting latitude and longitude in the TextView tv_location
tvLocation.setText("Latitude:" + latitude + ", Longitude:"+ longitude );
}
@Override
public void onProviderDisabled(String provider) {
// 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 boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
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// try this
**main.xml**
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp"
android:orientation="vertical">
<fragment
android:id="@+id/maps"
android:name="pl.mg6.android.maps.extensions.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
public class MyActivity extends FragmentActivity {
public static LocationManager mlocManager;
public static LocationListner mListner;
GoogleMap map;
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
map = getMapView();
map.setMyLocationEnabled(true);
try {
mlocManager = (LocationManager) getSystemService(Activity.LOCATION_SERVICE);
mListner = new LocationListner();
runOnUiThread(new Runnable() {
@Override
public void run() {
try {
try {
mlocManager.requestLocationUpdates(LocationManager.PASSIVE_PROVIDER, 0, 0, mListner);
} catch (Throwable e) {
e.printStackTrace();
}
mlocManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, mListner);
} catch (Throwable e) {
e.printStackTrace();
}
try {
mlocManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, mListner);
} catch (Throwable e) {
e.printStackTrace();
}
}
});
} catch (Throwable e) {
e.printStackTrace();
}
}
public GoogleMap getMapView() {
FragmentManager fm = getSupportFragmentManager();
SupportMapFragment f = (SupportMapFragment) fm.findFragmentById(R.id.maps);
// Getting GoogleMap object from the fragment
return f.getExtendedMap();
}
public void setMapMarker(LatLng loc){
map.addMarker(new MarkerOptions().position(loc).title("Istanbul"));
map.moveCamera(CameraUpdateFactory.newLatLngZoom(loc, 15));
map.animateCamera(CameraUpdateFactory.zoomTo(10), 2000, null);
}
class LocationListner implements LocationListener {
@Override
public void onLocationChanged(Location location) {
setMapMarker(new LatLng(location.getLatitude(),location.getLongitude()));
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
}
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In this line:
map.addMarker(new MarkerOptions().position(loc).title("Istanbul"));
loc is null
Also, you shouldn't call onLocationChanged () directly, it's a callback. The whole process is event driven, that is, when the GPS or the network gives you the location that this method triggers.
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