Options

To dictate what the map can/should do, regardless of its contents, it needs some guidance!

It provides options that can be categorized into three main parts:

• Initial positioning Defines the location of the map when it is first loaded

• Permanent rules Defines restrictions that last throughout the map's lifetime

• Event handling Defines methods that are called on specific map events

MapOptions class - flutter_map library - Dart APIpub.dev

Initial Positioning

One part of MapOptions responsibilities is to define how the map should be positioned when first loaded. There's two ways to do this (that are incompatible):

• center & zoom Defines the center coordinates of the map and a zoom level

• bounds Defines an area with two/four coordinates that the viewport should fit to

It is possible to also set the map's rotation in degrees, if you don't want it North (0°) facing initially.

Changing these properties after the map has already been built for the first time will have no effect: they only apply on initialisation.

To control the map programatically, use a MapController: Controller.

Permanent Rules

One part of MapOptions responsibilities is to define the restrictions and limitations of the map and what users can/cannot do with it.

You should check all the available options, but these are recommended for most maps:

• maxZoom (and minZoom) Limits how far the map can be zoomed by the user, to avoid showing empty tiles

• maxBounds Limits how far the map can be moved by the user to a coordinate-based boundary

• interactiveFlags - see InteractiveFlag for available options Limits what methods the user can interact with the map through (for example, preventing rotation)

• keepAlive If FlutterMap is located inside a PageView, ListView or another complex lazy layout, set this true to prevent the map from resetting to the Initial Positioning on rebuild

Instead of maxZoom (or in addition to), consider setting maxNativeZoom per TileLayer instead, to allow tiles to scale (and lose quality) on the final zoom level, instead of setting a hard limit.

Event Handling

When changes happen to FlutterMap's internal state, such as a change to the current position or zoom, it emits an event, some of which can be handled through callbacks, others of which can be handled through listening to a Stream.

If building a custom layer (Creating New Layers), consider using FlutterMapState directly instead.

Through MapController

If you are doing any of the following, setup a MapController, and listen to its mapEventStream instead:

• Capturing more than a couple of events & using the event's payload/data

• Needing the events in a single Stream

• Handling events that aren't available in the callbacks below (Through MapOptions)

Controller

Through MapOptions

The following callbacks are available:

• onTap

• onLongPress

• onPositionChanged

• onPointerDown/onPointerUp/onPointerHover/onPointerCancel

• onMapReady Primarily used for a MapController's Usage In initState()

• onMapEvent (does not expose event data) Prefer Through MapController