如何在谷歌地图安卓上添加标记?

Question

我是Android编程的初学者。我已经看过类似的问题和答案，但我仍然无法弄清楚为什么这不起作用。当我在模拟器上尝试此操作并单击某个位置时，没有出现标记。这是我的代码：

编辑：当我现在使用以下代码单击时，我得到一个标记。当我第二次单击地图时，它只会给我一个运行时异常(NullPointer 异常(：

public class MapViewFragment extends Fragment {
MapView mMapView;
private GoogleMap googleMap;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_map_view, container, false);
mMapView = (MapView) rootView.findViewById(R.id.mapView);
mMapView.onCreate(savedInstanceState);
mMapView.onResume();
Context context = getActivity().getApplicationContext();
final LocationsDB locationsDB = new LocationsDB(context);
try {
MapsInitializer.initialize(getActivity().getApplicationContext());
} catch (Exception e) {
e.printStackTrace();
}
mMapView.getMapAsync(new OnMapReadyCallback() {
@Override
public void onMapReady(GoogleMap mMap) {
googleMap = mMap;
googleMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
public void onMapClick(LatLng point) {
// Drawing marker on the map
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(point);
markerOptions.title(point.latitude + " : " + point.longitude);
googleMap.clear();
googleMap.animateCamera(CameraUpdateFactory.newLatLng(point));
googleMap.addMarker(markerOptions);
// Create location object
Location location = new Location(point.latitude, point.longitude);
// add location to SQLite database
locationsDB.insert(location);
}
});
}
});
return rootView;
}
}

日志消息：

7-20 07:33:00.076 5359-5359/? W/RcsService: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.rcs.service.service.a.a()' on a null object reference
at com.google.android.rcs.service.e.b(SourceFile:43)
at com.google.android.rcs.service.service.JibeService.onDestroy(SourceFile:162)
at android.app.ActivityThread.handleStopService(ActivityThread.java:3569)
at android.app.ActivityThread.-wrap26(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1703)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6540)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

07-20 07:33:00.079 5359-5359/? E/ActivityThread: Service com.google.android.rcs.service.service.JibeService has leaked IntentReceiver com.google.android.rcs.service.provisioning.RcsReconfigurationSmsReceiver@741339 that was originally registered here. Are you missing a call to unregisterReceiver()?
android.app.IntentReceiverLeaked: Service com.google.android.rcs.service.service.JibeService has leaked IntentReceiver com.google.android.rcs.service.provisioning.RcsReconfigurationSmsReceiver@741339 that was originally registered here. Are you missing a call to unregisterReceiver()?
at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:1310)
at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:1091)
at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:1397)
at android.app.ContextImpl.registerReceiver(ContextImpl.java:1370)
at android.app.ContextImpl.registerReceiver(ContextImpl.java:1358)
at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:603)
at com.google.android.rcs.service.provisioning.RcsSmsReceiver.a(SourceFile:12)
at com.google.android.rcs.service.h.g(SourceFile:230)
at com.google.android.rcs.service.h.<init>(SourceFile:212)
at com.google.android.rcs.service.service.a.<init>(SourceFile:13)
at com.google.android.rcs.service.e.a(SourceFile:32)
at com.google.android.rcs.service.service.JibeService.d(SourceFile:145)
at com.google.android.rcs.service.service.JibeService.onCreate(SourceFile:91)
at android.app.ActivityThread.handleCreateService(ActivityThread.java:3404)
at android.app.ActivityThread.-wrap4(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1683)
at android.os.Handler.dispatchMessage(Handler.java:105)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6540)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

Answer 1

在谷歌地图示例中查看此处 https://developers.google.com/maps/documentation/android-api/marker

如果您想在单击时添加标记，也可以查看此处： http://wptrafficanalyzer.in/blog/adding-marker-on-touched-location-of-google-maps-using-android-api-v2-with-supportmapfragment/

这个概念是像下面的代码一样做：

// Setting a click event handler for the map
googleMap.setOnMapClickListener(new OnMapClickListener() {
@Override
public void onMapClick(LatLng latLng) {
// Creating a marker
MarkerOptions markerOptions = new MarkerOptions();
// Setting the position for the marker
markerOptions.position(latLng);
// Setting the title for the marker.
// This will be displayed on taping the marker
markerOptions.title(latLng.latitude + " : " + latLng.longitude);
// Clears the previously touched position
googleMap.clear();
// Animating to the touched position
googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
// Placing a marker on the touched position
googleMap.addMarker(markerOptions);
}
});

Answer 2

//Show Marker on a Location
googleMap.addMarker(new MarkerOptions().position(TIMES_SQUARE));
//Change Default Color of Marker
googleMap.addMarker(new MarkerOptions()
.position(BROOKLYN_BRIDGE)
.title("First Pit Stop")
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)));
//Replace Default Marker Icon with Custom Image
googleMap.addMarker(new MarkerOptions()
.position(WALL_STREET)
.title("Wrong Turn!")
.icon(BitmapDescriptorFactory
.fromResource(R.drawable.my_flag)));

Answer 3

获取用户当前位置的经纬度

LatLng latLng = new LatLng(lat, lng);
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
mMap.clear();
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker));
markerOptions.getPosition();
mCurrLocationMarker = mMap.addMarker(markerOptions);

Answer 4

尝试这种方式。 传递纬度和经度值

// create marker
MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("Hello Maps");
// adding marker
googleMap.addMarker(marker);

Answer 5

地图活动中的这段代码对我有用：

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, GoogleMap.OnMapLongClickListener {
private GoogleMap mMap;
LocationManager locationManager;
LocationListener locationListener;
public void centreMapOnLocation(Location location, String title){
LatLng userLocation = new LatLng(location.getLatitude(),location.getLongitude());
mMap.clear();
mMap.addMarker(new MarkerOptions().position(userLocation).title(title));
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation,12));
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
centreMapOnLocation(lastKnownLocation,"Your Location");
}
}
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps2);
// 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;
mMap.setOnMapLongClickListener(this);
Intent intent = getIntent();
if (intent.getIntExtra("Place Number",0) == 0 ){
// Zoom into users location
locationManager = (LocationManager)this.getSystemService(Context.LOCATION_SERVICE);
locationListener = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
centreMapOnLocation(location,"Your Location");
}
@Override
public void onStatusChanged(String s, int i, Bundle bundle) {
}
@Override
public void onProviderEnabled(String s) {
}
@Override
public void onProviderDisabled(String s) {
}
};
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,0,0,locationListener);
Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
centreMapOnLocation(lastKnownLocation,"Your Location");
} else {
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},1);
}
} else {
Location placeLocation = new Location(LocationManager.GPS_PROVIDER);
placeLocation.setLatitude(MainActivity.location.get(intent.getIntExtra("Place Number",0)).latitude);
placeLocation.setLongitude(MainActivity.location.get(intent.getIntExtra("Place Number",0)).longitude);
centreMapOnLocation(placeLocation,MainActivity.places.get(intent.getIntExtra("Place Number",0)));
}

}

@Override
public void onMapLongClick(LatLng latLng) {
Geocoder geocoder = new Geocoder(getApplicationContext(), Locale.getDefault());
String adress ="";
try {
List<Address> listaddress = geocoder.getFromLocation(latLng.latitude,latLng.longitude,1);
if (listaddress != null && listaddress.size()>0){
if (listaddress.get(0).getThoroughfare() != null){
if (listaddress.get(0).getSubThoroughfare() != null){
adress += listaddress.get(0).getSubThoroughfare() + "";
}
adress += listaddress.get(0).getThoroughfare();
}
}
}catch (Exception e){
e.printStackTrace();
}
mMap.addMarker(new MarkerOptions().position(latLng).title(adress));
MainActivity.places.add(adress);
MainActivity.location.add(latLng);
MainActivity.arrayAdapter.notifyDataSetChanged();
Toast.makeText(this, "Location Saved..!", Toast.LENGTH_SHORT).show();
}

}