How to replace CachedNetworkTileProvider

[S-Man42]

Hi,

currently I am using the CachedNetworkTileProvider, which was removed here: 1a6b495

So, when updating to 0.11.0, how can I replace the CachedNetworkTileProvider properly to keep the caching functionality?

Kind regards!

[Swepilot]

Wow, his has been removed? What's the reason for that? My app heavily relies on that provider.

[rorystephenson]

I also didn't notice this removal.

Having a look at the other tile providers it seems like NetworkTileProvider should provide the same functionality. It uses NetworkImageWithRetry and the document indicates that this caches all images but when I tried a naive test it doesn't seem to do so.

I loaded some tiles, turned off internet in the emulator, restarted the app and the loaded tiles did not load without internet.

So I tried copying the old CachedNetworkTileProvider which does work in my test. So as a workaround you can add the old code to your project and use that as the tile provider:

class CachedNetworkTileProvider extends TileProvider {
  const CachedNetworkTileProvider();

  @override
  ImageProvider getImage(Coords<num> coords, TileLayerOptions options) {
    return CachedNetworkImageProvider(getTileUrl(coords, options));
  }
}

---

I think the removal of this code makes sense given that it uses cached_network_provider which in turn has sqflite as a dependency. If you don't need caching it's a shame to have sqflite as a dependency for no reason.

@johnpryan it may be worth adding a note about this in the Readme.

[mootw]

I believe disk caching was removed to get rid of the largest and slowest updating dependencies iirc. However this is not a bad thing. It should allow for more updates and less monolithic code.
Here are 2 ways to implement tile caching that could be added to the readme. I will look at making a pr for it.

1. Ram caching
   Create a new TileProvider. This is a built in Flutter image provider and will cache the tile images until the next app restart. This does not store images on disk or requires any extra dependencies.

class CachedNetworkTileProvider extends TileProvider {
  const CachedNetworkTileProvider();

  @override
  ImageProvider getImage(Coords<num> coords, TileLayerOptions options) {
    return ImageProvider(getTileUrl(coords, options));
  }
}

2. Disk cache (requires a cache dependency or custom imageprovider)
   Same code as above; except instead of using the built in flutter imageProvider we will use a custom image provider or dependency. In this case we will use cached_network_image.

import 'package:cached_network_image/cached_network_image.dart';

class CachedNetworkTileProvider extends TileProvider {
  const CachedNetworkTileProvider();

  @override
  ImageProvider getImage(Coords<num> coords, TileLayerOptions options) {
    return CachedNetworkImageProvider(getTileUrl(coords, options));
  }
}