2️⃣Prepare For Downloading

BaseRegions must be converted to DownloadableRegions before they can be used to download tiles.

These contain the original BaseRegion, but also some other information necessary for downloading, such as zoom levels and URL templates.

final downloadableRegion = region.toDownloadable(
    minZoom: 1,
    maxZoom: 18,
    options: TileLayer(
        urlTemplate: '<your tile server>',
        userAgentPackageName: 'com.example.app',
    ),
),

toDownloadable method - BaseRegion class - flutter_map_tile_caching library - Dart APIpub.dev

The TileLayer passed to the options parameter must include both a urlTemplate (or WMS configuration) and a userAgentPackageName, unless it is only being used to check the number of tiles in the region.

Checking Number Of Tiles

Before continuing to downloading the region, you can use check() to count the number of tiles it will attempt to download. This is accessible through FMTCStore().download.

The method takes the DownloadableRegion generated above, and will return an int number of tiles. For larger regions, this may take a few seconds.

This figure will not take into account any skipped sea tiles or skipped existing tiles, as those are handled at the time of download.