问题
I was wondering whether it was possible to do such a thing. I know that one would need to modify some of the existing code to pull this off but I was wondering if anyone had any direction on where to look and how to do this.
I am placing a few custom tiles on a specific area on the map as a replacement for OSM tiles providers but need them to be stored in the /assets/ folder. Any ideas?
回答1:
I use the nexts classes to do that.
import java.io.InputStream;
import org.osmdroid.ResourceProxy.string;
import org.osmdroid.tileprovider.util.StreamUtils;
import android.content.res.AssetManager;
import android.graphics.drawable.Drawable;
public class AssetsTileSource extends CustomBitmapTileSourceBase {
private final AssetManager mAssetManager;
public AssetsTileSource(final AssetManager assetManager, final String aName, final string aResourceId,
final int aZoomMinLevel, final int aZoomMaxLevel, final int aTileSizePixels,
final String aImageFilenameEnding) {
super(aName, aResourceId, aZoomMinLevel, aZoomMaxLevel, aTileSizePixels, aImageFilenameEnding);
mAssetManager = assetManager;
}
@Override
public Drawable getDrawable(final String aFilePath) {
InputStream inputStream = null;
try {
inputStream = mAssetManager.open(aFilePath);
if (inputStream != null) {
final Drawable drawable = getDrawable(inputStream);
return drawable;
}
} catch (final Throwable e) {
// Tile does not exist in assets folder.
// Ignore silently
} finally {
if (inputStream != null) {
StreamUtils.closeStream(inputStream);
}
}
return null;
}
}
MapTileFileAssetsProvider.java
public class MapTileFileAssetsProvider extends MapTileModuleProviderBase {
protected ITileSource mTileSource;
public MapTileFileAssetsProvider(final ITileSource pTileSource) {
super(OpenStreetMapTileProviderConstants.NUMBER_OF_TILE_FILESYSTEM_THREADS, OpenStreetMapTileProviderConstants.TILE_FILESYSTEM_MAXIMUM_QUEUE_SIZE);
mTileSource = pTileSource;
}
@Override
public boolean getUsesDataConnection() {
return false;
}
@Override
protected String getName() {
return "Assets Folder Provider";
}
@Override
protected String getThreadGroupName() {
return "assetsfolder";
}
@Override
protected Runnable getTileLoader() {
return new TileLoader();
}
@Override
public int getMinimumZoomLevel() {
return mTileSource != null ? mTileSource.getMinimumZoomLevel() : MAXIMUM_ZOOMLEVEL;
}
@Override
public int getMaximumZoomLevel() {
return mTileSource != null ? mTileSource.getMaximumZoomLevel() : MINIMUM_ZOOMLEVEL;
}
@Override
public void setTileSource(final ITileSource pTileSource) {
mTileSource = pTileSource;
}
private class TileLoader extends MapTileModuleProviderBase.TileLoader {
@Override
public Drawable loadTile(final MapTileRequestState pState) throws CantContinueException {
if (mTileSource == null) {
return null;
}
final MapTile pTile = pState.getMapTile();
String path = mTileSource.getTileRelativeFilenameString(pTile);
Drawable drawable;
try {
drawable = mTileSource.getDrawable(path);
} catch (final LowMemoryException e) {
// low memory so empty the queue
throw new CantContinueException(e);
}
return drawable;
}
}
}
And
import java.io.File;
import java.io.InputStream;
import java.util.Random;
import org.osmdroid.ResourceProxy;
import org.osmdroid.ResourceProxy.string;
import org.osmdroid.tileprovider.ExpirableBitmapDrawable;
import org.osmdroid.tileprovider.MapTile;
import org.osmdroid.tileprovider.constants.OpenStreetMapTileProviderConstants;
import org.osmdroid.tileprovider.tilesource.ITileSource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
public abstract class CustomBitmapTileSourceBase implements ITileSource,
OpenStreetMapTileProviderConstants {
private static final Logger logger = LoggerFactory.getLogger(CustomBitmapTileSourceBase.class);
private static int globalOrdinal = 0;
private final int mMinimumZoomLevel;
private final int mMaximumZoomLevel;
private final int mOrdinal;
protected final String mName;
protected final String mImageFilenameEnding;
protected final Random random = new Random();
private final int mTileSizePixels;
private final string mResourceId;
public CustomBitmapTileSourceBase(final String aName, final string aResourceId,
final int aZoomMinLevel, final int aZoomMaxLevel, final int aTileSizePixels,
final String aImageFilenameEnding) {
mResourceId = aResourceId;
mOrdinal = globalOrdinal++;
mName = aName;
mMinimumZoomLevel = aZoomMinLevel;
mMaximumZoomLevel = aZoomMaxLevel;
mTileSizePixels = aTileSizePixels;
mImageFilenameEnding = aImageFilenameEnding;
}
@Override
public int ordinal() {
return mOrdinal;
}
@Override
public String name() {
return mName;
}
public String pathBase() {
return mName;
}
public String imageFilenameEnding() {
return mImageFilenameEnding;
}
@Override
public int getMinimumZoomLevel() {
return mMinimumZoomLevel;
}
@Override
public int getMaximumZoomLevel() {
return mMaximumZoomLevel;
}
@Override
public int getTileSizePixels() {
return mTileSizePixels;
}
@Override
public String localizedName(final ResourceProxy proxy) {
return proxy.getString(mResourceId);
}
@Override
public Drawable getDrawable(final String aFilePath) {
try {
// default implementation will load the file as a bitmap and create
// a BitmapDrawable from it
final Bitmap bitmap = BitmapFactory.decodeFile(aFilePath);
if (bitmap != null) {
return new ExpirableBitmapDrawable(bitmap);
} else {
// if we couldn't load it then it's invalid - delete it
try {
new File(aFilePath).delete();
} catch (final Throwable e) {
logger.error("Error deleting invalid file: " + aFilePath, e);
}
}
} catch (final OutOfMemoryError e) {
logger.error("OutOfMemoryError loading bitmap: " + aFilePath);
System.gc();
}
return null;
}
@Override
public String getTileRelativeFilenameString(final MapTile tile) {
final StringBuilder sb = new StringBuilder();
sb.append(pathBase());
sb.append('/');
sb.append(tile.getX());
sb.append('_');
sb.append(tile.getY());
sb.append('_');
sb.append(tile.getZoomLevel());
sb.append(imageFilenameEnding());
return sb.toString();
}
@Override
public Drawable getDrawable(final InputStream aFileInputStream) {
try {
// default implementation will load the file as a bitmap and create
// a BitmapDrawable from it
final Bitmap bitmap = BitmapFactory.decodeStream(aFileInputStream);
if (bitmap != null) {
return new ExpirableBitmapDrawable(bitmap);
}
System.gc();
} catch (final OutOfMemoryError e) {
logger.error("OutOfMemoryError loading bitmap");
System.gc();
//throw new LowMemoryException(e);
}
return null;
}
public final class LowMemoryException extends Exception {
private static final long serialVersionUID = 146526524087765134L;
public LowMemoryException(final String pDetailMessage) {
super(pDetailMessage);
}
public LowMemoryException(final Throwable pThrowable) {
super(pThrowable);
}
}
}
Modify method getTileRelativeFilenameString() to get yout tiles (i use the next format: x_y_zoom.png)
Example:
mapView = new MapView(getApplicationContext(), 256);
mapView.setClickable(true);
mapView.setTag("Mapa");
mapView.setTileSource(TileSourceFactory.MAPNIK);
mapView.setMultiTouchControls(true);
mapView.setUseDataConnection(true);
MapTileModuleProviderBase moduleProvider =
new MapTileFileAssetsProvider(ASSETS_TILE_SOURCE);
SimpleRegisterReceiver simpleReceiver =
new SimpleRegisterReceiver(getApplicationContext());
MapTileProviderArray tileProviderArray =
new MapTileProviderArray(ASSETS_TILE_SOURCE, simpleReceiver,
new MapTileModuleProviderBase[] { moduleProvider });
TilesOverlay tilesOverlay =
new TilesOverlay(tileProviderArray, getApplicationContext());
mapView.getOverlays().add(tilesOverlay);
回答2:
Instead to read directly from assets I copy/deploy the maptiles zipped (following osmdroid map tiles directory structure format) into osmdroid maptiles directory and then declare 3 tile providers, archive, cache and online provider.
public class MapTileProviderAssets extends MapTileProviderArray
implements IMapTileProviderCallback {
private static final String LOG_TAG = "MapTileProviderAssets";
private static final String ASSETS_MAP_DIRECTORY = "map";
private static final String SDCARD_PATH = Environment.getExternalStorageDirectory().getPath();
private static final String OSMDROID_MAP_FILE_SOURCE_DIRECTORY = "osmdroid";
private static final String OSMDROID_MAP_FILE_SOURCE_DIRECTORY_PATH =
SDCARD_PATH + "/" + OSMDROID_MAP_FILE_SOURCE_DIRECTORY;
public MapTileProviderAssets(final Context pContext) {
this(pContext, TileSourceFactory.DEFAULT_TILE_SOURCE);
}
public MapTileProviderAssets(final Context pContext, final ITileSource pTileSource) {
this(pContext, new SimpleRegisterReceiver(pContext),
new NetworkAvailabliltyCheck(pContext), pTileSource);
}
public MapTileProviderAssets(final Context pContext, final IRegisterReceiver pRegisterReceiver,
final INetworkAvailablityCheck aNetworkAvailablityCheck,
final ITileSource pTileSource) {
super(pTileSource, pRegisterReceiver);
final TileWriter tileWriter = new TileWriter();
// copy assets delivered in apk into osmdroid map source dir
// load zip archive first, then cache, then online
final List<String> zipArchivesRelativePathInAssets =
listArchives(pContext.getAssets(), ASSETS_MAP_DIRECTORY);
for (final String zipFileRelativePathInAssets : zipArchivesRelativePathInAssets) {
final String copiedFilePath = copyAssetFile(
pContext.getAssets(), zipFileRelativePathInAssets,
OSMDROID_MAP_FILE_SOURCE_DIRECTORY);
Log.d(LOG_TAG, String.format(
"Archive zip file copied into map source directory %s", copiedFilePath));
}
// list zip files in map archive directory
final Set<String> setZipFileArchivesPath = new HashSet<String>();
FileTools.listFiles(setZipFileArchivesPath, new File(
OSMDROID_MAP_FILE_SOURCE_DIRECTORY_PATH), ".zip", true);
final Set<IArchiveFile> setZipFileArchives = new HashSet<IArchiveFile>();
for (final String zipFileArchivesPath : setZipFileArchivesPath) {
final File zipfile = new File(zipFileArchivesPath);
final IArchiveFile archiveFile = ArchiveFileFactory.getArchiveFile(zipfile);
if (archiveFile != null) {
setZipFileArchives.add(archiveFile);
}
setZipFileArchives.add(archiveFile);
Log.d(LOG_TAG, String.format(
"Archive zip file %s added to map source ", zipFileArchivesPath));
}
final MapTileFileArchiveProvider archiveProvider;
Log.d(LOG_TAG, String.format(
"%s archive zip files will be used as source", setZipFileArchives.size()));
if (setZipFileArchives.size() > 0) {
final IArchiveFile[] pArchives =
setZipFileArchives.toArray(new IArchiveFile[setZipFileArchives.size()]);
archiveProvider = new MapTileFileArchiveProvider(
pRegisterReceiver, pTileSource, pArchives);
} else {
archiveProvider = new MapTileFileArchiveProvider(
pRegisterReceiver, pTileSource);
}
mTileProviderList.add(archiveProvider);
// cache
final MapTileFilesystemProvider fileSystemProvider =
new MapTileFilesystemProvider(pRegisterReceiver, pTileSource);
mTileProviderList.add(fileSystemProvider);
// online tiles
final MapTileDownloader downloaderProvider =
new MapTileDownloader(pTileSource, tileWriter, aNetworkAvailablityCheck);
mTileProviderList.add(downloaderProvider);
}
public static List<String> listArchives(final AssetManager assetManager,
final String subDirectory) {
final List<String> listArchives = new ArrayList<String>();
try {
final String[] lstFiles = assetManager.list(subDirectory);
if (lstFiles != null && lstFiles.length > 0) {
for (final String file : lstFiles) {
if (isZip(file)) {
listArchives.add(subDirectory + "/" + file);
}
// filter files (xxxxx.xxx format) and parse only directories,
// with out this all files are parsed and
// the process is VERY slow
// WARNNING: we could have directories with dot for versioning
else if (isDirectory(file)) {// (file.lastIndexOf(".") != (file.length() - 4)) {
listArchives(assetManager, subDirectory + "/" + file);
}
}
}
} catch (final IOException e) {
Log.w(LOG_TAG, String.format("List error: can't list %s, exception %s",
subDirectory, Log.getStackTraceString(e)));
} catch (final Exception e) {
Log.w(LOG_TAG, String.format("List error: can't list %s, exception %s",
subDirectory, Log.getStackTraceString(e)));
}
return listArchives;
}
private static boolean isZip(final String file) {
return file.endsWith(".zip");
}
private static boolean isDirectory(final String file) {
return file.lastIndexOf(".") != (file.length() - 4);
}
private static String copyAssetFile(final AssetManager assetManager,
final String assetRelativePath,
final String destinationDirectoryOnSdcard) {
InputStream in = null;
OutputStream out = null;
final String newfilePath = SDCARD_PATH + "/" +
destinationDirectoryOnSdcard + "/" + assetRelativePath;
final File newFile = new File(newfilePath);
// copy file only if it doesn't exist yet
if (!newFile.exists()) {
Log.d(LOG_TAG, String.format(
"Copy %s map archive in assets into %s", assetRelativePath, newfilePath));
try {
final File directory = newFile.getParentFile();
if (!directory.exists()) {
if (directory.mkdirs()) {
// Log.d(LOG_TAG, "Directory created: " + directory.getAbsolutePath());
}
}
in = assetManager.open(assetRelativePath);
out = new FileOutputStream(newfilePath);
copyFile(in, out);
in.close();
in = null;
out.flush();
out.close();
out = null;
} catch (final Exception e) {
Log.e(LOG_TAG, "Exception during copyAssetFile: " + Log.getStackTraceString(e));
}
}
return newfilePath;
}
private static void copyFile(final InputStream in, final OutputStream out) throws IOException {
final byte[] buffer = new byte[1024];
int read;
while ((read = in.read(buffer)) != -1) {
out.write(buffer, 0, read);
}
}
}
来源：https://stackoverflow.com/questions/12693684/osmdroid-loading-custom-offline-tiles-from-assets-folder