Robert Robert - 5 months ago 25
Android Question

Android assets retrieve embedded font for Typeface

I've managed to embed a font which I can access through Typeface.createFromAsset, however, there is also the "file:///android_asset/.." protocol.

I tried using "file:///android_asset/fonts/myfont.ttf" for Typeface.createFromFile, but this does not work ? Strange as I would have thought that file:///android_asset is handled by the system and thus Typeface would be able to get an InputStream ?

So my specific question is: Why doesn't the file:///android_asset/ protocol work with Typeface.createFromFile ?

Answer

The solution I opted for was to write a binary array into a cache file, then use Typeface.createFromFile(path) with the cache file.

The solution looks like this:

final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();

public static String bytesToHex (byte[] bytes)
{
    char[] hexChars = new char[bytes.length * 2];

    for (int j = 0; j < bytes.length; ++j)
    {
        int v = bytes[j] & 0xff;
        hexChars[j * 2]     = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0f];
    }

    return new String (hexChars);
}

final private java.util.Map dataCache = new java.util.HashMap();

synchronized private final File getDataCacheFile (byte[] data)
{
    try
    {
        java.security.MessageDigest digest = java.security.MessageDigest.getInstance ("MD5");
        digest.update (data);

        String key = bytesToHex (digest.digest());

        if (dataCache.containsKey (key))
            return (File) dataCache.get (key);

        File f = new File (this.getCacheDir(), "bindata_" + key);
        f.delete();
        FileOutputStream os = new FileOutputStream (f);
        os.write (data, 0, data.length);
        dataCache.put (key, f);
        return f;
    }
    catch (Throwable e) {}

    return null;
}

private final void clearDataCache()
{
    java.util.Iterator it = dataCache.values().iterator();

    while (it.hasNext())
    {
        File f = (File) it.next();
        f.delete();
    }
}

public final Typeface getTypeFaceFromByteArray (byte[] data)
{
    try
    {
        File f = getDataCacheFile (data);

        if (f != null)
            return Typeface.createFromFile (f);
    }
    catch (Exception e)
    {
        Log.e ("<tag>", e.toString());
    }

    return null;
}
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