How do i add a marker on maps in android programming -
so reason when try adding marker geopoint, marker fails show @ given location. tried researching problem reason code seems follow researched on. can guide me in right direction?
import android.content.context; import android.location.criteria; import android.location.geocoder; import android.location.location; import android.location.locationmanager; import android.support.v4.app.fragmentactivity; import android.os.bundle; import android.util.log; import android.widget.toast; import com.google.android.gms.maps.cameraupdatefactory; import com.google.android.gms.maps.googlemap; import com.google.android.gms.maps.supportmapfragment; import com.google.android.gms.maps.model.cameraposition; import com.google.android.gms.maps.model.latlng; import com.google.android.gms.maps.model.markeroptions; import java.text.decimalformat; public class mapsactivity extends fragmentactivity { private googlemap mmap; // might null if google play services apk not available. @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_maps); setupmapifneeded(); } @override protected void onresume() { super.onresume(); setupmapifneeded(); } /** * sets map if possible (i.e., google play services apk correctly * installed) , map has not been instantiated.. ensure ever * call {@link #setupmap()} once when {@link #mmap} not null. * <p/> * if isn't installed {@link supportmapfragment} (and * {@link com.google.android.gms.maps.mapview mapview}) show prompt user * install/update google play services apk on device. * <p/> * user can return fragmentactivity after following prompt , correctly * installing/updating/enabling google play services. since fragmentactivity may not * have been destroyed during process (it * stopped or paused), {@link #oncreate(bundle)} may not called again should call * method in {@link #onresume()} guarantee called. */ private void setupmapifneeded() { // null check confirm have not instantiated map. if (mmap == null) { // try obtain map supportmapfragment. mmap = ((supportmapfragment) getsupportfragmentmanager().findfragmentbyid(r.id.map)) .getmap(); // check if successful in obtaining map. if (mmap != null) { setupmap(); } } } /** * can add markers or lines, add listeners or move camera. in case, * add marker near africa. * <p/> * should called once , when sure {@link #mmap} not null. */ private void setupmap() { mmap.addmarker(new markeroptions().position(new latlng(0, 0)).title("marker").snippet("snippet")); // enable mylocation layer of google map mmap.setmylocationenabled(true); // locationmanager object system service location_service locationmanager locationmanager = (locationmanager) getsystemservice(context.location_service); // create criteria object retrieve provider criteria criteria = new criteria(); // name of best provider string provider = locationmanager.getbestprovider(criteria, true); // current location location mylocation = locationmanager.getlastknownlocation(provider); // set map type mmap.setmaptype(googlemap.map_type_normal); // latitude of current location location location = locationmanager.getlastknownlocation(locationmanager.gps_provider); if (location != null) { double longitude = location.getlongitude(); double latitude = location.getlatitude(); // longitude of current location // create latlng object current location latlng latlng = new latlng(latitude, longitude); // show current location in google map mmap.movecamera(cameraupdatefactory.newlatlng(latlng)); // zoom in google map //latlng mycoordinates = new latlng(latitude, longitude); //cameraupdate yourlocation = cameraupdatefactory.newlatlngzoom(mycoordinates, 20); //mmap.animatecamera(yourlocation); mmap.animatecamera(cameraupdatefactory.zoomto(20)); mmap.addmarker(new markeroptions().position(new latlng(latitude, longitude)).title("you here!").snippet("consider located")); latlng tolatlng = new latlng(40.6937, 73.9859); mmap.addmarker(new markeroptions().position( new latlng(40.6937, 73.9859)).title("you location here!").snippet("consider located")); } } public void onfinish() { // code here after map rendered } }
the main issue mention:
the marker fails show @ given location
it looks main reason getlastknownlocation() returning null, never gets code sets marker @ current position.
instead of calling method, can set location listener, explicitly request new location.
i cleaned code bit, , got working. note removed use of getlastknownlocation(), , moved logic had in there onlocationchanged() callback.
i added functionality remove previous "current location" marker, , add new 1 every time location changes.
also note 1 marker showing @ equator near africa due line, commented out:
mmap.addmarker(new markeroptions().position(new latlng(0, 0)).title("marker").snippet("snippet")); here full updated class code:
import android.content.context; import android.location.location; import android.location.locationlistener; import android.location.locationmanager; import android.support.v4.app.fragmentactivity; import android.os.bundle; import com.google.android.gms.maps.cameraupdatefactory; import com.google.android.gms.maps.googlemap; import com.google.android.gms.maps.supportmapfragment; import com.google.android.gms.maps.model.bitmapdescriptorfactory; import com.google.android.gms.maps.model.latlng; import com.google.android.gms.maps.model.marker; import com.google.android.gms.maps.model.markeroptions; import android.location.criteria; public class mapsactivity extends fragmentactivity implements locationlistener { private googlemap mmap; // might null if google play services apk not available. locationmanager locationmanager; marker marker; @override protected void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_maps); setupmapifneeded(); } @override protected void onresume() { super.onresume(); setupmapifneeded(); } @override protected void onpause() { super.onpause(); //remove location listener if (locationmanager != null){ locationmanager.removeupdates(this); } } private void setupmapifneeded() { // null check confirm have not instantiated map. if (mmap == null) { // try obtain map supportmapfragment. mmap = ((supportmapfragment) getsupportfragmentmanager().findfragmentbyid(r.id.map)) .getmap(); // check if successful in obtaining map. if (mmap != null) { setupmap(); } } } private void setupmap() { //this marker @ equator near africa //mmap.addmarker(new markeroptions().position(new latlng(0, 0)).title("marker").snippet("snippet")); // enable mylocation layer of google map mmap.setmylocationenabled(true); mmap.setmaptype(googlemap.map_type_hybrid); mmap.getuisettings().setzoomcontrolsenabled(true); mmap.getuisettings().setmylocationbuttonenabled(true); mmap.getuisettings().setcompassenabled(true); mmap.getuisettings().setrotategesturesenabled(true); mmap.getuisettings().setzoomgesturesenabled(true); // locationmanager object system service location_service locationmanager = (locationmanager) getsystemservice(context.location_service); if (locationmanager.isproviderenabled(locationmanager.network_provider)) { locationmanager.requestlocationupdates(locationmanager.network_provider, 1000, 0, this); } if (locationmanager.isproviderenabled(locationmanager.gps_provider)) { locationmanager.requestlocationupdates(locationmanager.gps_provider, 1000, 0, this); } } public void onfinish() { // code here after map rendered } @override public void onlocationchanged(location location) { double longitude = location.getlongitude(); double latitude = location.getlatitude(); // create latlng object current location latlng latlng = new latlng(latitude, longitude); // show current location in google map mmap.movecamera(cameraupdatefactory.newlatlng(latlng)); mmap.animatecamera(cameraupdatefactory.zoomto(15)); if (marker != null) { marker.remove(); } marker = mmap.addmarker(new markeroptions().position(new latlng(latitude, longitude)) .title("you here!").snippet("consider located") .icon(bitmapdescriptorfactory.defaultmarker(bitmapdescriptorfactory.hue_magenta))); } @override public void onstatuschanged(string provider, int status, bundle extras) { } @override public void onproviderenabled(string provider) { } @override public void onproviderdisabled(string provider) { } } result:
edit:
you picked interesting spot put hard-coded marker.
i replaced marker code this:
latlng tolatlng = new latlng(40.6937, 73.9859); // create latlng object current location latlng latlng = new latlng(40.6937, 73.9859); // show current location in google map mmap.movecamera(cameraupdatefactory.newlatlng(latlng)); mmap.animatecamera(cameraupdatefactory.zoomto(15)); if (marker != null) { marker.remove(); } marker = mmap.addmarker(new markeroptions().position(new latlng(40.6937, 73.9859)) .title("you here!").snippet("consider located") .icon(bitmapdescriptorfactory.defaultmarker(bitmapdescriptorfactory.hue_magenta))); and placed marker @ given location. note there strange effect going on due different satellite images.
initial result:
zoomed out see are!
Comments
Post a Comment