I am adding a large amount of GeoJSON data into Mapbox in an Android app. This makes scrolling through the map very slow on higher zoom levels. For this reason I would like to change the input data based on the current zoom level. I looked for a function like getCurrentZoomlevel(), but all I could find was a getMaxZoomLevel() function in the MapView class and this only gives my the maximum possible zoom level. Is there a function that I can call which gives me the current zoom level?
For this solution to work, I would also need to remove and add certain polygons dynamically based on the zoom level. Is it possible to remove polygons without reloading the entire map?
Starting with 4.0.0 of the Mapbox Android SDK, interaction with the map happens using the MapboxMap object, not the MapView. It sounds like you are trying to add a zoom listener which doesn't exist but a onCameraChangeListener does and from that you can check the zoom level.
mapboxMap.setOnCameraChangeListener(new MapboxMap.OnCameraChangeListener() {
@Override
public void onCameraChange(CameraPosition position) {
...
if (position.zoom < 12) {
...
}
}
});
If your GeoJSON file is large and you are trying to draw polygons/polylines you might want to have a look at the Style API we will be introducing in 4.2.0. It allows you to add geojson layers and style them. If you are interested I'd recommend taking a look at the examples found in the Mapbox Android Demo App. This Github issue shows off a bunch of the examples I added.
EDIT: forgot to mention to remove polygons or polylines from the map you have a few options. Either use mapboxMap.removeAnnotations(); to remove all annotations from the map or mapboxMap.removePolygon(); to remove a polygon for example. removePolygon takes in a Polygon object which you'll need to assign when adding the polygon to the map:
Polygon polygon = map.addPolygon(new PolygonOptions()
.addAll(<List of points making up polygon>)
.setFillColor(color));