Android Studio 谷歌地图自定义地图，只想显示自定义地图但利用谷歌地图功能

Question

I understand that the title might add a little confusion, I'll do my best to explain it here. I'm trying to create an app for a charity, and they want a map for their site that they can navigate around. I'm currently using the google maps overlay function. I've almost got the desired outcome, but there are a few things I can't get my head around.

    @Override
    public void onMapReady(GoogleMap googleMap) {
    //LatLng NEWARK = new LatLng(51.251115, -0.599319);

    LatLngBounds NewarkBounds = new LatLngBounds(
            new LatLng(50.807686, -0.430219),
            new LatLng(50.811414, -0.424310)

    );

    mMap = googleMap;
    mMap.getUiSettings().setMapToolbarEnabled(false);
    //mMap.addMarker(new MarkerOptions().position(NEWARK).title("Reserve"));


    LatLng myPosition = new LatLng(latitude,longitude);


    GroundOverlayOptions newarkMap = new GroundOverlayOptions()
            .image(BitmapDescriptorFactory.fromResource(R.drawable.maptest))
            .positionFromBounds(NewarkBounds)
            .visible(false);


    if((myPosition.latitude <= PLACETEXT && myPosition.latitude >=PLACETEXT ) && 
    (myPosition.longitude >= -PLACETEXT && myPosition.longitude <= -PLACETEXT )){
        newarkMap.visible(true);
        mMap.setMyLocationEnabled(true);

    }
    else {
        mMap.setMyLocationEnabled(false);
    }

    GroundOverlay imageOverlay = mMap.addGroundOverlay(newarkMap);


    mMap.setMyLocationEnabled(true);
    mMap.setOnMyLocationButtonClickListener(this);
    mMap.setOnMyLocationClickListener(this);


    mMap.moveCamera(CameraUpdateFactory.newLatLng(new LatLng(myPosition.latitude, 
    myPosition.longitude)));
    mMap.setMapType(0);
    mMap.setLatLngBoundsForCameraTarget(NewarkBounds);
}

This is my OnMapReady function, I've tried playing around with the zoom function etc, I'm new to this stuff so I might be doing something fundamentally wrong.

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">

<fragment
    android:id="@+id/map"
    android:name="com.google.android.gms.maps.SupportMapFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
</fragment>

</androidx.constraintlayout.widget.ConstraintLayout>

Layout file ^^

The image above shows whats currently displaying, ignore the map it is a placeholder, What I'm trying to achieve is to be fully zoomed in the person's current location, and to only be able to drag around the photo to the boundary of the LatLngs of the map?

Answer 1

This is possible. Please have a look at Google's documentation on Setting boundaries .

Code snippet to set the camera to the greatest possible zoom level within bounds:

private GoogleMap mMap;
// Create a LatLngBounds that includes Australia.
private LatLngBounds AUSTRALIA = new LatLngBounds(
  new LatLng(-44, 113), new LatLng(-10, 154));

// Set the camera to the greatest possible zoom level that includes the bounds
mMap.moveCamera(CameraUpdateFactory.newLatLngBounds(AUSTRALIA, 0));

Centering the camera within bounds:

private GoogleMap mMap;
private LatLngBounds AUSTRALIA = new LatLngBounds(
  new LatLng(-44, 113), new LatLng(-10, 154));

mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(AUSTRALIA.getCenter(), 10));

Restricting the user's scrolling and panning within bounds:

private GoogleMap mMap;
// Create a LatLngBounds that includes the city of Adelaide in Australia.
private LatLngBounds ADELAIDE = new LatLngBounds(
  new LatLng(-35.0, 138.58), new LatLng(-34.9, 138.61));
// Constrain the camera target to the Adelaide bounds.
mMap.setLatLngBoundsForCameraTarget(ADELAIDE);

Hope this helps!