Android: how to get the walking distance between two geo coordinats?

Question

I used this query URL

http://maps.google.com/maps?q=from+A+to+B&output=kml

,which is given in the answer to this question. But after I tried it, it doesn't work with coordinates. It works with address names tho. I guess I could use google's geocoding to get the addresses first. But I wonder if there is another way to get the walking distance between two coordinates?