Basemap gallery toolkit component

[martinoyovo]

The BasemapGallery is a UI component that lets a user browse a collection of basemaps and apply a selection to a connected GeoModel via a BasemapGalleryController.

The basemaps shown in the gallery are provided by the controller (defaults, a portal, or custom items), and the current selection is tracked by the controller.

Features

• Displays basemaps as a grid, list, or automatically switches based on available width.
• Shows selection state and exposes selection events via the controller.

Usage

Provide a BasemapGalleryController and place the gallery in your widget tree.

late final ArcGISMap _map;
late final BasemapGalleryController _controller;

@override
void initState() {
  super.initState();
  _map = ArcGISMap.withBasemapStyle(BasemapStyle.arcGISTopographic);
  _controller = BasemapGalleryController(geoModel: _map);
}

@override
Widget build(BuildContext context) {
  return BasemapGallery(controller: _controller);
}

Simulator.Screen.Recording.-.iPhone.17.Pro.Max.-.2025-12-31.at.13.12.19.mov

[changanxian]

This should be

(_spatialReference.wkid == referenceSpatialReference.wkid) 

[martinoyovo]

We’re trying to detect a spatial reference mismatch; comparing only the WKID can miss mismatches for others.

[changanxian]

It is nice to have different folders to classify the MVC classes. Since each folder only has one class, and the class name has been self-identified, we could move the classes under one folder and focus on the public API, hiding the internal implementation in a different folder.

[martinoyovo]

Thank you again for all your feedback! I’ve incorporated the changes into the repo, and the branch has been updated. Please take a look when you have a chance, and let me know if there’s anything else I can improve. I’m always open to suggestions. Thanks!

[PaulAllanSturm]

added a few more comments

[jenmerritt]

I've built the API ref and done a re-review of the public API and design - have a few more queries below. Overall it's feeling a lot closer to design though.

I plan to do some user testing and throw some data at it on Monday 👀

[jenmerritt]

This has come along way @martinoyovo , nice work. To the point where I've really hammered it in user quality testing today. I think some of these should be written up as individual tasks, but take the time to read through and maybe we can sync up on them to go through. Perhaps you can also experiment with some of the things I've been testing.