android - 谷歌地图多个标记不显示，一个显示另一个隐藏反之亦然

Question

您好，我想在从 firebase 检索纬度和经度后显示多个标记，所以我将这些值放在循环中，但它显示一个可见，另一个隐藏，反之亦然，但我想同时显示它们的标记。

下面是我的代码。

public class MapsActivity extends AppCompatActivity
        implements LocationListener, GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,OnMapReadyCallback {

    GoogleApiClient mGoogleApiClient;
    LocationRequest mLocationRequest;
    String lat,lon;
    LatLng che2;

    private GoogleMap mMap;
    static final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;

    vehicle_lat_long msend = new vehicle_lat_long();
    ArrayList<vehicle_lat_long> markersArray = new ArrayList<vehicle_lat_long>();


    FirebaseDatabase database = FirebaseDatabase.getInstance();
    DatabaseReference myRef = database.getReference();

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
        // Add a marker in Sydney and move the camera

    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);

        // Get Location Manager and check for GPS & Network location services
        LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE);

        if(!(lm.isProviderEnabled(LocationManager.GPS_PROVIDER)) ||
                !(lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER))) {
            // Build the alert dialog
            AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("Location Services Not Active");
            builder.setMessage("Please enable Location Services and GPS");
            builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialogInterface, int i) {
                    // Show location settings when the user acknowledges the alert dialog
                    Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                    startActivity(intent);
                }
            });
            Dialog alertDialog = builder.create();
            alertDialog.setCanceledOnTouchOutside(false);
            alertDialog.show();
        }

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(2000);
        mLocationRequest.setFastestInterval(2000);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        this.RetriveData();

    }

    ValueEventListener postListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {


        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            // Getting Post failed, log a message
            //Log.w(TAG, "loadPost:onCancelled", databaseError.toException());
            // ...
        }
    };


    @Override
    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    @Override
    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }

    @Override
    public void onLocationChanged(Location location) {
        if (location != null) {
            String strLocation =
                    DateFormat.getTimeInstance().format(location.getTime()) + "\n" +
                            "Latitude=" + location.getLatitude() + "\n" +
                            "Longitude=" + location.getLongitude();



         lat =  String.valueOf(location.getLatitude());
         lon =  String.valueOf(location.getLongitude());

            msend.setLatitude(lat);
            msend.setLongtitude(lon);
            msend.setCarname(Global.car_name);
               myRef.child(Global.trip_name).child(Global.car_name).setValue(msend);
        }
    }


    //Retrive Data
    private void RetriveData()
    {
        myRef.child(Global.trip_name).addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String prevChildKey) {
                Log.e("MyTag", dataSnapshot.getKey());

            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String prevChildKey)
            {


               msend = dataSnapshot.getValue(vehicle_lat_long.class);
               markersArray.add(msend);
               mMap.clear();

            for(int i = 0 ; i < markersArray.size() ; i++ )
                {
                    double l1= Double.parseDouble(msend.getLatitude());
                    double l2= Double.parseDouble(msend.getLongtitude());
                    che2 = new LatLng(l1,l2);

                    mMap.addMarker(new MarkerOptions().position(che2).title(msend.getCarname()).icon(BitmapDescriptorFactory.fromResource(R.drawable.cursor)));   mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(che2, 17.0f));

                }


            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot)
            {

            }
            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String prevChildKey)
            {

            }

            @Override
            public void onCancelled(DatabaseError databaseError)
            {

            }

        });

    }

Answer 1

根据我的评论，循环被正确调用，但用于每个标记的细节不会改变，因为您一直从 msend 而不是 markersArray 调用它.尝试更换

double l1= Double.parseDouble(msend.getLatitude());
double l2= Double.parseDouble(msend.getLongtitude());

到

double l1= Double.parseDouble(markersArray.get(i).getLatitude());
double l2= Double.parseDouble(markersArray.get(i).getLongtitude());