How to use google maps offline in react native

Question

I'm trying to enable users to use maps offline in my react native App, I'm using react-native-maps

I want to provide the offline mode just for a predefined area (let's say a city), therefore I need to download all the needed tiles which will be a huge number of images, so I wonder if there is a way in the google map API to download an area of the map (like in google map app)?
from the documentation it is possible to enable caching, which I do the same thing (according to the doc) however, In my case I don't want to cache every place that the user go to, as I said I just want to cache/download a predefined area.
EDIT 1
react-native-maps support offline navigation for that, I need to use this code :

 <LocalTile pathTemplate={this.state.pathTemplate} tileSize={256}/>

with pathTemplate point to my tiles location which had to have the following hierarchy :

location/{z}/{x}/{y}

therefore my real probleme is how to get the tiles for my area.
I can do it manually by saving tiles from the google maps tile server , however I don't know if it is legal and also it will take a lot of time and calculation (when zooming in, I need to calculate the coordinated of the next tiles )
so It will be nice, if google map API provide a way to download an area's tile (with needed zoom),
another alternative would be using another map provider like OpenStreetMAp , but here also, I need to find a way to download all tiles at once

Answer 1

At this time the only offline react-native module that supports offline mapping is react-native-mapbox-gl.

<MapView>
<LocalTile
pathTemplate="../pathToLocalStoredTile.png"
tileSize={126}
/>
</MapView>

This might give you some support.

As Google Maps SDK does not have this implemented, the only offline possibility is to use custom tiles.

Answer 2

If you want do download tales you can use React-native MapBox's SnapShotManager.

Refer to the SnapShotManager docs: https://github.com/react-native-mapbox-gl/maps/blob/master/docs/snapshotManager.md

// creates a temp file png of base map
const uri = await MapboxGL.snapshotManager.takeSnap({
  centerCoordinate: [-74.126410, 40.797968],
  width: width,
  height: height,
  zoomLevel: 12,
  pitch: 30,
  heading: 20,
  styleURL: MapboxGL.StyleURL.Dark,
  writeToDisk: true, // Create a temporary file
});

// creates base64 png of base map without logo
const uri = await MapboxGL.snapshotManager.takeSnap({
  centerCoordinate: [-74.126410, 40.797968],
  width: width,
  height: height,
  zoomLevel: 12,
  pitch: 30,
  heading: 20,
  styleURL: MapboxGL.StyleURL.Dark,
  withLogo: false, // Disable Mapbox logo (Android only)
});

// creates snapshot with bounds
const uri = await MapboxGL.snapshotManager.takeSnap({
  bounds: [[-74.126410, 40.797968], [-74.143727, 40.772177]],
  width: width,
  height: height,
  styleURL: MapboxGL.StyleURL.Dark,
});