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OfflineManager.md

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<MapLibreGL.offlineManager />

OfflineManager implements a singleton (shared object) that manages offline packs.
All of this class’s instance methods are asynchronous, reflecting the fact that offline resources are stored in a database.
The shared object maintains a canonical collection of offline packs.

methods

createPack(options[, progressListener][, errorListener])

Creates and registers an offline pack that downloads the resources needed to use the given region offline.

arguments
Name Type Required Description
options OfflineCreatePackOptions Yes Create options for a offline pack that specifices zoom levels, style url, and the region to download.
progressListener Callback No Callback that listens for status events while downloading the offline resource.
errorListener Callback No Callback that listens for status events while downloading the offline resource. 
const progressListener = (offlineRegion, status) => console.log(offlineRegion, status);
const errorListener = (offlineRegion, err) => console.log(offlineRegion, err);

await MapLibreGL.offlineManager.createPack({
  name: 'offlinePack',
  styleURL: 'mapbox://...',
  minZoom: 14,
  maxZoom: 20,
  bounds: [[neLng, neLat], [swLng, swLat]]
}, progressListener, errorListener)

invalidatePack(name)

Invalidates the specified offline pack. This method checks that the tiles in the specified offline pack match those from the server. Local tiles that do not match the latest version on the server are updated.This is more efficient than deleting the offline pack and downloading it again. If the data stored locally matches that on the server, new data will not be downloaded.

arguments
Name Type Required Description
name String Yes Name of the offline pack. 
await MapLibreGL.offlineManager.invalidatePack('packName')

deletePack(name)

Unregisters the given offline pack and allows resources that are no longer required by any remaining packs to be potentially freed.

arguments
Name Type Required Description
name String Yes Name of the offline pack. 
await MapLibreGL.offlineManager.deletePack('packName')

invalidateAmbientCache()

Forces a revalidation of the tiles in the ambient cache and downloads a fresh version of the tiles from the tile server.
This is the recommend method for clearing the cache.
This is the most efficient method because tiles in the ambient cache are re-downloaded to remove outdated data from a device.
It does not erase resources from the ambient cache or delete the database, which can be computationally expensive operations that may carry unintended side effects.

arguments
Name Type Required Description 
await MapLibreGL.offlineManager.invalidateAmbientCache();

clearAmbientCache()

Erases resources from the ambient cache.
This method clears the cache and decreases the amount of space that map resources take up on the device.

arguments
Name Type Required Description 
await MapLibreGL.offlineManager.clearAmbientCache();

setMaximumAmbientCacheSize(size)

Sets the maximum size of the ambient cache in bytes. Disables the ambient cache if set to 0.
This method may be computationally expensive because it will erase resources from the ambient cache if its size is decreased.

arguments
Name Type Required Description
size Number Yes Size of ambient cache. 
await MapLibreGL.offlineManager.setMaximumAmbientCacheSize(5000000);

resetDatabase()

Deletes the existing database, which includes both the ambient cache and offline packs, then reinitializes it.

arguments
Name Type Required Description 
await MapLibreGL.offlineManager.resetDatabase();

getPacks()

Retrieves all the current offline packs that are stored in the database.

arguments
Name Type Required Description 
const offlinePacks = await MapLibreGL.offlineManager.getPacks();

getPack(name)

Retrieves an offline pack that is stored in the database by name.

arguments
Name Type Required Description
name String Yes Name of the offline pack. 
const offlinePack = await MapLibreGL.offlineManager.getPack();

mergeOfflineRegions(path)

Sideloads offline db

arguments
Name Type Required Description
path String Yes Path to offline tile db on file system. 
await MapLibreGL.offlineManager.mergeOfflineRegions(path);

setTileCountLimit(limit)

Sets the maximum number of tiles that may be downloaded and stored on the current device.
Consult the Terms of Service for your map tile host before changing this value.

arguments
Name Type Required Description
limit Number Yes Map tile limit count. 
MapLibreGL.offlineManager.setTileCountLimit(1000);

setProgressEventThrottle(throttleValue)

Sets the period at which download status events will be sent over the React Native bridge.
The default is 500ms.

arguments
Name Type Required Description
throttleValue Number Yes event throttle value in ms. 
MapLibreGL.offlineManager.setProgressEventThrottle(500);

subscribe(packName, progressListener, errorListener)

Subscribe to download status/error events for the requested offline pack.
Note that createPack calls this internally if listeners are provided.

arguments
Name Type Required Description
packName String Yes Name of the offline pack.
progressListener Callback Yes Callback that listens for status events while downloading the offline resource.
errorListener Callback Yes Callback that listens for status events while downloading the offline resource. 
const progressListener = (offlinePack, status) => console.log(offlinePack, status)
const errorListener = (offlinePack, err) => console.log(offlinePack, err)
MapLibreGL.offlineManager.subscribe('packName', progressListener, errorListener)

unsubscribe(packName)

Unsubscribes any listeners associated with the offline pack.
It's a good idea to call this on componentWillUnmount.

arguments
Name Type Required Description
packName String Yes Name of the offline pack. 
MapLibreGL.offlineManager.unsubscribe('packName')