import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
public Drawable loadTile(final ITileSource pTileSource, final MapTile pTile) throws Exception{
	// Check the tile source to see if its file is available and if so, then render the
	// drawable and return the tile
	final File file = getFile(pTileSource, pTile);
	if (!file.exists()) {
		return null;
	}

	final Drawable drawable = pTileSource.getDrawable(file.getPath());

	// Check to see if file has expired
	final long now = System.currentTimeMillis();
	final long lastModified = file.lastModified();
	final boolean fileExpired = lastModified < now - mMaximumCachedFileAge;

	if (fileExpired && drawable != null) {
		if (Configuration.getInstance().isDebugMode()) {
			Log.d(IMapView.LOGTAG,"Tile expired: " + pTile);
		}
		ExpirableBitmapDrawable.setState(drawable, ExpirableBitmapDrawable.EXPIRED);
	}

	return drawable;
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
protected Drawable loadTile(MapTileRequestState req) throws CantContinueException {
    InputStream inputStream;
    try {
        final String filePath = tileSource.getTileRelativeFilenameString(req.getMapTile());

        inputStream = assetManager.open(filePath);
        return new ExpirableBitmapDrawable(BitmapFactory.decodeStream(inputStream));
    } catch (final IOException e) {
        return null;
    }
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
public synchronized Drawable getDrawable(int tileX, int tileY, int zoom) throws LowMemoryException
 {	
if(tileOutOfBounds(tileX, tileY, zoom))
	return null;
  
   final Tile tile = new Tile(tileX, tileY, (byte)zoom);
   MapGeneratorJob mapGeneratorJob = new MapGeneratorJob(tile, 
                                                         "ooot",                                                           
                                                         jobParameters_,
                                                         debugSettings_);

   final Bitmap tileBitmap = Bitmap.createBitmap(Tile.TILE_SIZE, Tile.TILE_SIZE, Bitmap.Config.RGB_565);
   boolean success = mapGenerator_.executeJob(mapGeneratorJob, tileBitmap);
   return success ?  new ExpirableBitmapDrawable(tileBitmap) : null;
 }
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
public Drawable loadTile(final MapTile pMapTile) {
    final Bitmap bitmap = approximateTileFromLowerZoom(pMapTile);
    if (bitmap != null) {
        final BitmapDrawable drawable = new BitmapDrawable(bitmap);
        ExpirableBitmapDrawable.setState(drawable, ExpirableBitmapDrawable.SCALED);
        return drawable;
    }
    return null;
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
/**
 * A tile has loaded.
 */
protected void tileLoaded(final MapTileRequestState pState, final Drawable pDrawable) {
	if (Configuration.getInstance().isDebugTileProviders()) {
		Log.d(IMapView.LOGTAG,"TileLoader.tileLoaded() on provider: " + getName() + " with tile: "
				+ pState.getMapTile());
	}
	removeTileFromQueues(pState.getMapTile());
	ExpirableBitmapDrawable.setState(pDrawable, ExpirableBitmapDrawable.UP_TO_DATE);
	pState.getCallback().mapTileRequestCompleted(pState, pDrawable);
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
/**
 * A tile has loaded but it's expired.
 * Return it <b>and</b> send request to next provider.
 */
protected void tileLoadedExpired(final MapTileRequestState pState, final Drawable pDrawable) {
	if (Configuration.getInstance().isDebugTileProviders()) {
		Log.d(IMapView.LOGTAG,"TileLoader.tileLoadedExpired() on provider: " + getName()
				+ " with tile: " + pState.getMapTile());
	}
	removeTileFromQueues(pState.getMapTile());
	ExpirableBitmapDrawable.setState(pDrawable, ExpirableBitmapDrawable.EXPIRED);
	pState.getCallback().mapTileRequestExpiredTile(pState, pDrawable);
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
protected void tileLoadedScaled(final MapTileRequestState pState, final Drawable pDrawable) {
	if (Configuration.getInstance().isDebugTileProviders()) {
		Log.d(IMapView.LOGTAG,"TileLoader.tileLoadedScaled() on provider: " + getName()
				+ " with tile: " + pState.getMapTile());
	}
	removeTileFromQueues(pState.getMapTile());
	ExpirableBitmapDrawable.setState(pDrawable, ExpirableBitmapDrawable.SCALED);
	pState.getCallback().mapTileRequestExpiredTile(pState, pDrawable);
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
public Drawable loadTile(final ITileSource pTileSource, final MapTile pTile) throws Exception{
    InputStream inputStream = null;
    try {
        final long index = getIndex(pTile);
        final Cursor cur = getTileCursor(getPrimaryKeyParameters(index, pTileSource), queryColumns);
        byte[] bits=null;
        long expirationTimestamp=0;

        if(cur.getCount() != 0) {
            cur.moveToFirst();
            bits = cur.getBlob(cur.getColumnIndex(DatabaseFileArchive.COLUMN_TILE));
            expirationTimestamp = cur.getLong(cur.getColumnIndex(SqlTileWriter.COLUMN_EXPIRES));
        }
        cur.close();
        if (bits==null) {
            if (Configuration.getInstance().isDebugMode()) {
                Log.d(IMapView.LOGTAG,"SqlCache - Tile doesn't exist: " +pTileSource.name() + pTile);
            }
            return null;
        }
        inputStream = new ByteArrayInputStream(bits);
        final Drawable drawable = pTileSource.getDrawable(inputStream);
        // Check to see if file has expired
        final long now = System.currentTimeMillis();
        final boolean fileExpired = expirationTimestamp < now;

        if (fileExpired && drawable != null) {
            if (Configuration.getInstance().isDebugMode()) {
                Log.d(IMapView.LOGTAG,"Tile expired: " + pTileSource.name() +pTile);
            }
            ExpirableBitmapDrawable.setState(drawable, ExpirableBitmapDrawable.EXPIRED);
        }
        return drawable;
    } finally {
        if (inputStream != null) {
            StreamUtils.closeStream(inputStream);
        }
    }
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
public Drawable loadTile(final MapTileRequestState pState) throws CantContinueException {

	ITileSource tileSource = mTileSource.get();
	if (tileSource == null) {
		return null;
	}

	final MapTile tile = pState.getMapTile();

	// if there's no sdcard then don't do anything
	if (!getSdCardAvailable()) {
		if (OpenStreetMapTileProviderConstants.DEBUGMODE) {
			Log.d(IMapView.LOGTAG,"No sdcard - do nothing for tile: " + tile);
		}
		return null;
	}

	// Check the tile source to see if its file is available and if so, then render the
	// drawable and return the tile
	final File file = new File(safeTilePathBase,
			tileSource.getTileRelativeFilenameString(tile) + OpenStreetMapTileProviderConstants.TILE_PATH_EXTENSION);
	if (file.exists()) {

		try {
			final Drawable drawable = tileSource.getDrawable(file.getPath());

			// Check to see if file has expired
			final long now = System.currentTimeMillis();
			final long lastModified = file.lastModified();
			final boolean fileExpired = lastModified < now - mMaximumCachedFileAge;

			if (fileExpired && drawable != null) {
				if (OpenStreetMapTileProviderConstants.DEBUGMODE) {
					Log.d(IMapView.LOGTAG,"Tile expired: " + tile);
				}
				ExpirableBitmapDrawable.setDrawableExpired(drawable);
			}

			return drawable;
		} catch (final LowMemoryException e) {
			// low memory so empty the queue
			Log.w(IMapView.LOGTAG,"LowMemoryException downloading MapTile: " + tile + " : " + e);
			throw new CantContinueException(e);
		}
	}

	// If we get here then there is no file in the file cache
	return null;
}
 

import org.osmdroid.tileprovider.ExpirableBitmapDrawable; //导入依赖的package包/类
@Override
public Drawable loadTile(final MapTileRequestState pState) throws CantContinueException {

	if (mTileSource == null) {
		return null;
	}

	final MapTile tile = pState.getMapTile();

	// if there's no sdcard then don't do anything
	if (!getSdCardAvailable()) {
		if (DEBUGMODE) {
			logger.debug("No sdcard - do nothing for tile: " + tile);
		}
		return null;
	}

	// Check the tile source to see if its file is available and if so,
	// then render the
	// drawable and return the tile
	final File file = new File(TILE_PATH_BASE, mTileSource.getTileRelativeFilenameString(tile) + TILE_PATH_EXTENSION);
	if (file.exists()) {

		try {
			final Drawable drawable = mTileSource.getDrawable(file.getPath());

			// Check to see if file has expired
			final long now = System.currentTimeMillis();
			final long lastModified = file.lastModified();
			boolean fileExpired = lastModified < now - mMaximumCachedFileAge;

			if (fileExpired) {
				boolean isConTypeMobile = networkAvailablityCheck.getCellularDataNetworkAvailable();
				if (isConTypeMobile) {
					fileExpired = !isConTypeMobile;
					Log.d(TAG, "File Expired with Cellular " + networkAvailablityCheck.getCellularDataNetworkAvailable() + " ==> Expired " + fileExpired);
				}
			}
			if (fileExpired) {
				if (DEBUGMODE) {
					logger.debug("Tile expired: " + tile);
				}
				drawable.setState(new int[] { ExpirableBitmapDrawable.EXPIRED });
			}

			return drawable;
		} catch (final LowMemoryException e) {
			// low memory so empty the queue
			logger.warn("LowMemoryException downloading MapTile: " + tile + " : " + e);
			throw new CantContinueException(e);
		}
	}

	// If we get here then there is no file in the file cache
	return null;
}