如何在谷歌地图android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这个并单击一个位置时，没有出现任何标记。这是我的代码：

编辑：当我现在点击以下代码时，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 Google 地图示例中查看此处 https://developers.google.com/maps/documentation/android-api/marker

如果你想在点击时添加标记，你也可以看这里： http://wptrafficanalyzer.in/blog/adding-marker-on-touched-location-of-google-maps-using-android-api-v2-with-supportmapfragment/

概念是像下面的代码那样做：

// 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

以这种方式尝试。 传递您的纬度和经度值

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

// adding marker
googleMap.addMarker(marker);

Answer 5

MapsActivity 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();

}

}