Google's origin Android API doesn't support WebP until ICS(Android 4.0).
This project is a native(C++) implementation based on Google's open source project Chromium. So you need not to care about the compatibility.
Features
public static native Bitmap nativeDecodeByteArray(byte[] data, BitmapFactory.Options options);
public static native byte[] nativeEncodeBitmap(Bitmap bitmap, int quality);
public static boolean isWebP(byte[] data);
Just build the cpp files under jni folder with NDK. And then enjoy it!