Question

我的标记出现问题，因为每次Latitude和Longitude更改时，它都会创建一个新标记而不是覆盖旧标记。我正在获取多个标记，因此我将其存储在ArrayList内。我的String busRoute和int passenger也变为空。所以这是我的代码。我希望有人能解决我的问题。

private String name, busNum, busRoute, currentLocation, estimatedTime, availableSeat, lat, lng;
double latitude, longitude;
int passenger;

public void markerDriver() {
    markerArray = new ArrayList<>();
    Firebase ref = new Firebase(Config.FIREBASE_URL_DRIVER);
    ref.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.getChildrenCount() == 0) {
                markerInfo();
            } else {
                for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                    if (snapshot.child("availableSeat").exists() && snapshot.child("latitude").exists() && snapshot.child("longitude").exists() && snapshot.child("estimatedTime").exists()) {
                        name = snapshot.child("driversName").getValue().toString().trim();
                        busNum = snapshot.child("busNum").getValue().toString().trim();
                        lat = snapshot.child("latitude").getValue().toString().trim();
                        lng = snapshot.child("longitude").getValue().toString().trim();
                        availableSeat = snapshot.child("availableSeat").getValue().toString().trim();
                        estimatedTime = snapshot.child("estimatedTime").getValue().toString().trim();
                        latitude = Double.valueOf(lat);
                        longitude = Double.valueOf(lng);

                        convertLatLong();
                        getTotalPass();
                        markerArray.add(new Driver(name, busNum, busRoute, passenger, latitude, longitude, currentLocation, estimatedTime));
                    }
                }
                for (i = 0; i < markerArray.size(); i++) {
                    createMarker(markerArray.get(i).getDriversName(), markerArray.get(i).getBusNum(), markerArray.get(i).getRoute(), markerArray.get(i).getTotalPassenger(), markerArray.get(i).getLatitude(), markerArray.get(i).getLongitude(), markerArray.get(i).getLocation(), markerArray.get(i).getEstimatedTime());
                }
            }
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            Toast.makeText(MainMapActivity.this, "markerDriver: " + firebaseError.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });

public void convertLatLong() {
    Geocoder geocoder;
    List<android.location.Address> addresses;
    geocoder = new Geocoder(this, Locale.getDefault());

    try {
        addresses = geocoder.getFromLocation(latitude, longitude, 1);
        if (addresses.get(0).getAddressLine(0) != null) {
            currentLocation = addresses.get(0).getAddressLine(0) + ", " + addresses.get(0).getLocality();
        } else {
            currentLocation = addresses.get(0).getLocality();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void getTotalPass() {
    busRef = new Firebase(Config.FIREBASE_URL_BUSNUMBER);
    Query bus = busRef.orderByChild("busNum").equalTo(busNum);
    bus.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                passenger = Integer.valueOf(snapshot.child("capacity").getValue().toString().trim()) - Integer.valueOf(availableSeat);
                busRoute = snapshot.child("route").getValue().toString().trim();
                Toast.makeText(MainMapActivity.this, "routeGetTotalPass: " + busRoute + ":::" + passenger, Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {
            Toast.makeText(MainMapActivity.this, "getTotalPass: " + firebaseError.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });
}

createMarker

protected void createMarker(String driversName, final String busNum, String route, final int totalPass, double latitude, double longitude, String location, String estimatedTime) {
    Marker marker = mMap.addMarker(new MarkerOptions()
            .position(new LatLng(latitude, longitude))
            .title(location)
            .snippet("Driver's Name: " + driversName + "\nBus number: " + busNum + "\nRoute: " + route + "\nTotal Passenger: " + totalPass + "\nEstimated time: " + estimatedTime));
    mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
        @Override
        public boolean onMarkerClick(com.google.android.gms.maps.model.Marker marker) {
            dialogInfo(marker);
            return true;
        }
    });
}

Answer 1

在添加新标记

之前删除旧标记

                   if (marker != null) {
                    marker.remove();
                    } 
                    convertLatLong();
                    getTotalPass();
                    markerArray.add(new Driver(name, busNum, busRoute, passenger, latitude, longitude, currentLocation, estimatedTime));

另一种方法是在添加新标记

之前清除GoogleMap

googleMap.clear();

在onCreate声明之前

标记标记;

然后改变

 protected void createMarker(String driversName, final String busNum, String route, final int totalPass, double latitude, double longitude, String location, String estimatedTime) {
marker = mMap.addMarker(new MarkerOptions()
        .position(new LatLng(latitude, longitude))
        .title(location)
        .snippet("Driver's Name: " + driversName + "\nBus number: " + busNum + "\nRoute: " + route + "\nTotal Passenger: " + totalPass + "\nEstimated time: " + estimatedTime));
mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
    @Override
    public boolean onMarkerClick(com.google.android.gms.maps.model.Marker marker) {
        dialogInfo(marker);
        return true;
    }
});
}

Answer 2

首先声明标记ArrayList<Marker> markerList=new ArrayList<>();的列表然后将您的方法创建标记更改为

protected void createMarker(String driversName, final String busNum, String route, final int totalPass, double latitude, double longitude, String location, String estimatedTime) {
    boolean isOld = false;
    for (Marker m:markerList) {
        if (m.getTitle().equals(location)) {
            m.setPosition(new LatLng(latitude, longitude));
            isOld=true;
            break;
        }
    }
    if (!isOld) {
        Marker marker = mMap.addMarker(new MarkerOptions()
                .position(new LatLng(latitude, longitude))
                .title(location)
                .snippet("Driver's Name: " + driversName + "\nBus number: " + busNum + "\nRoute: " + route + "\nTotal Passenger: " + totalPass + "\nEstimated time: " + estimatedTime));
    markerList.add(marker);
    }
    mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
        @Override
        public boolean onMarkerClick(com.google.android.gms.maps.model.Marker marker) {
            dialogInfo(marker);
            return true;
        }
    });
}

这对我有用

Answer 3

如果你想删除特定的标记，那么使用带有整数作为id和marker对象的weakhash map，然后你可以根据索引id删除它。

有关详情，请查看此内容 - https://stackoverflow.com/a/35363423/2128166

Answer 4

我使用以下代码制作：

string first_value = "4";
string second_value = "5";

//compare two values
if ( first_value < second_value){
    cout << "4 is smaller than 5" <<endl;
}else{
    cout << "5 is smaller than 4" <<endl;
}

删除上一个标记和标记的信息失败

4 个答案: