RMDatabaseCache导致指数内存增加

Question

我正在尝试使用Mapbox下载地图以供离线使用。但运气不好。内存使用量呈指数增长，应用程序最终崩溃。

我这样做。

RMMapboxSource *onlineSource = [[RMMapboxSource alloc] initWithMapID:kMapboxMapID];

RMMapView *mapView = [[RMMapView alloc] initWithFrame:self.view.bounds andTilesource:onlineSource];

CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake(37.774527, -122.420091);

mapView.zoom = 50;
mapView.maxZoom = 50;
for (id cache in mapView.tileCache.tileCaches)
{
  if ([cache isKindOfClass:[RMDatabaseCache class]])
  {
RMDatabaseCache *dbCache = (RMDatabaseCache *)cache;
NSLog(@"current cache size: %lld", dbCache.fileSize);

if (dbCache.fileSize < 20000)
{
  [mapView.tileCache setBackgroundCacheDelegate:self];
  NSInteger minZoom = tileSource.minZoom;
  NSInteger maxZoom = tileSource.maxZoom; // here I am fetching all but this might be too much
  [mapView.tileCache beginBackgroundCacheForTileSource:tileSource     southWest:tileSource.latitudeLongitudeBoundingBox.southWest northEast:tileSource.latitudeLongitudeBoundingBox.northEast minZoom:minZoom maxZoom:maxZoom];
}

break;
}
}

但内存拍摄和应用程序崩溃。 有谁可以帮帮我？提前谢谢。