MaplySimpleTileFetcher

Objective-C

@interface MaplySimpleTileFetcher : NSObject <MaplyTileFetcher>

Swift

class MaplySimpleTileFetcher : NSObject, MaplyTileFetcher

Simple Tile Fetcher is meant for sub classing.

Some data sources aren't all that complex.  You read from a local source,
you return the data.  Something else turns it into visible objects.  Simple.

To implement one of those, subclass the Simple Tile Fetcher and let it do the
tricky bits.

  • Your Subclass must call this init method

    Declaration

    Objective-C

    - (nullable instancetype)initWithName:(NSString *_Nonnull)name
                              minZoom:(int)minZoom
                              maxZoom:(int)maxZoom;

    Swift

    init?(name: String, minZoom: Int32, maxZoom: Int32)

  • The quad paging loader variants need a TileInfo object, even if it’s very simple

    Declaration

    Objective-C

    - (nullable NSObject<MaplyTileInfoNew> *)tileInfo;

    Swift

    func tileInfo() -> MaplyTileInfoNew?

  • Dispatch queue the data fetcher is doing its work on

    Declaration

    Objective-C

    @property (nonnull) dispatch_queue_t queue;

    Swift

    var queue: DispatchQueue { get set }

  • Set by default. We won’t every return an error on failing to load. Useful for sparse data sets

    Declaration

    Objective-C

    @property _Bool neverFail;

    Swift

    var neverFail: Bool { get set }

  • Name used for debugging

    Declaration

    Objective-C

    @property NSString *_Nonnull name;

    Swift

    var name: String { get set }

  • Min zoom level

    Declaration

    Objective-C

    - (int)minZoom;

    Swift

    func minZoom() -> Int32

  • Max zoom level

    Declaration

    Objective-C

    - (int)maxZoom;

    Swift

    func maxZoom() -> Int32

  • Override dataForTile:tileID: to return your own data for a given tile. The fetchInfo can be a custom object (if you set it up that way) or you can just use the tileID argument.

    You'll be called on the dispatch queue.

You can return either an NSData or a MaplyLoaderReturn

    Declaration

    Objective-C

    - (id _Nullable)dataForTile:(id _Nonnull)fetchInfo tileID:(MaplyTileID)tileID;

    Swift

    func data(forTile fetchInfo: Any, tileID: MaplyTileID) -> Any?

  • Override the shutdown method.

    Call the superclass shutdown method *first* and then run your own shutdown.

    Declaration

    Objective-C

    - (void)shutdown;

    Swift

    func shutdown()