为什么地图不能正确充电？

Question

I have uploaded the map from a zip file. After loaded if you change the zoom level, the part that is outside the mobile screen is not loaded correctly. Why doesn't it work?

Thanks!

Answer 1

Actual answer if there were no tiles in .zip no tiles will be shown on subject zoom level.

But if you already have tiles to be shown from lower zoom level - yes you can try!

There is a method, which you can try by your own

map.getTileProvider().rescaleCache({some parameters olso is here});

Another, maybe not so simple decision, is described below.

It looks like you`re using simple approach like:

XYTileSource tileSource = new XYTileSource("map",
MIN_ZOOM_LEVEL, MAX_ZOOM_LEVEL, 256, ".png", new String[]{});

map.setTileSource(tileSource);

However you can go over to steps that are more complicated:

XYTileSource tileSource = new XYTileSource("map", 
MIN_ZOOM_LEVEL, MAX_ZOOM_LEVEL,256, ".png", new String[]{});

SimpleRegisterReceiver simpleRegisterReceiver =
            new SimpleRegisterReceiver(getContext());

MapTileModuleProviderBase[] mapTileModuleProviderBases = 
            new MapTileModuleProviderBase[1];

mapTileModuleProviderBases[0] = 
            new MyMapTileFileArchiveProvider(simpleRegisterReceiver,
                tileSource, mapArchiveFiles);
//mapArchiveFiles - your Array of IArchiveFile
//IArchiveFile iArchiveFile = ArchiveFileFactory.getArchiveFile(file);
//file - your .zip

MapTileProviderArray mapTileProviderArray =
            new MapTileProviderArray(tileSource,
                    simpleRegisterReceiver, mapTileModuleProviderBases);

map.setTileProvider(mapTileProviderArray);

Question - what is a MyMapTileFileArchiveProvider class? It's not just subClass of MapTileFileArchiveProvider but both of them have common parent:

   public class MyMapTileFileArchiveProvider extends   MapTileFileStorageProviderBase {}

At this point you`re welcome to copy-paste default implementation of MapTileFileArchiveProvider class to your own class, and look for this method:

private synchronized InputStream getInputStream(final MapTile pTile,
        final ITileSource tileSource) {
    for (final IArchiveFile archiveFile : mArchiveFiles) {
        if (archiveFile!=null) {final InputStream in = 
            archiveFile.getInputStream(tileSource, pTile);
            if (in != null) {
                if (Configuration.getInstance().isDebugMode()) {
                    Log.d(IMapView.LOGTAG, "Found tile " + pTile + " in " + archiveFile);
                }

                return in;
            }
        }
    }

    //Good place for your logic (as we call it - crutch)
    //to look for available tiles for subject area on lower zoom level
    //Do not surrender before return null!

    return null;
}

Thanks for paying attention:)