诀窍是您需要将文件从应用程序包复制到设备存储，否则您无法打开 MBtiles 文件。
- 将您的 map.mbtiles 文件放入/assets文件夹，而不是 res/raw/
- 在首次应用程序启动期间复制文件。我只是在你的onCreate()方法中调用copyAssets() 。请参阅下面的代码，这会将资产下的所有内容复制到应用程序私有文件夹。请注意，您可能希望在此处添加对典型文件写入问题案例的处理：SD 卡不可用、无写入权限（您的应用程序必须具有 WRITE_EXTERNAL_STORAGE 权限）、空间不足，也许还有更多。
- 使用正确的路径创建数据源和图层：
示例代码：
@Override
public void onCreate(Bundle savedInstanceState) {
// create mapview, settings...
copyAssets();
try {
MBTilesRasterDataSource dataSource = new MBTilesRasterDataSource(
new EPSG3857(), 0, 19,
getExternalFilesDir(null).getAbsolutePath()+"/map.mbtiles",
false, this);
RasterLayer mbLayer = new RasterLayer(dataSource, 0);
// use setBaseLayer() if this is main layer, addLayer() if it is overlay layer
mapView.getLayers().setBaseLayer(mbLayer);
// recenter map to coverage
HashMap<String, String> dbMetaData = dataSource.getDatabase().getMetadata();
String center = dbMetaData.get("center");
String bounds = dbMetaData.get("bounds");
if(center != null){
// format: long,lat,zoom
String[] centerParams = center.split(",");
mapView.setFocusPoint(mapView.getLayers().getBaseLayer().getProjection().fromWgs84(Double.parseDouble(centerParams[0]), Double.parseDouble(centerParams[1])));
mapView.setZoom(Float.parseFloat(centerParams[2]));
Log.debug ("center to point "+Arrays.toString(centerParams));
}else if(bounds != null){
// format: longMin,latMin,longMax,latMax
String[] boundsParams = bounds.split(",");
MapPos bottomLeft = mapView.getLayers().getBaseProjection().fromWgs84(Double.parseDouble(boundsParams[0]), Double.parseDouble(boundsParams[1]));
MapPos topRight = mapView.getLayers().getBaseProjection().fromWgs84(Double.parseDouble(boundsParams[2]), Double.parseDouble(boundsParams[3]));
Log.debug ("center to bounds "+bottomLeft.x+","+topRight.y+","+topRight.x+","+bottomLeft.y);
mapView.setBoundingBox(new Bounds(bottomLeft.x,topRight.y,topRight.x,bottomLeft.y), false);
// check that zoom is within given range
int[] zoomRange = dataSource.getDatabase().getZoomRange();
if(mapView.getZoom() < zoomRange[0]){
mapView.setZoom(zoomRange[0]+1);
}
if(mapView.getZoom() > zoomRange[1]){
mapView.setZoom(zoomRange[1]-1);
}
}else{
// bulgaria
mapView.setFocusPoint(mapView.getLayers().getBaseLayer().getProjection().fromWgs84(26.483230800000037, 42.550218000000044));
// zoom - 0 = world, like on most web maps
mapView.setZoom(5.0f);
Log.debug("center to default");
}
} catch (IOException e) {
Log.error(e.getMessage());
}
// ...
}
private void copyAssets() {
AssetManager assetManager = getAssets();
String[] files = null;
try {
files = assetManager.list("");
} catch (IOException e) {
Log.error("Failed to get asset file list." + e.getLocalizedMessage());
}
for(String filename : files) {
InputStream in = null;
OutputStream out = null;
try {
in = assetManager.open(filename);
File outFile = new File(getExternalFilesDir(null), filename);
if(!outFile.exists()){
out = new FileOutputStream(outFile);
copyFile(in, out);
out.flush();
out.close();
out = null;
}
in.close();
in = null;
} catch(IOException e) {
Log.error("Failed to copy asset file: " + filename + "\n" + e.getLocalizedMessage());
}
}
}
private void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[32 * 1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}