Draw line in google map follow the route

I would like a same solution like here:

Sample

but I didn't find a solution nowhere. The 开发者_运维知识库big problem is the follow the route, so I can draw line beetween 2 points, but it's not good. What is the solution? Thanks.

Use the Directions API. You can find more information on how to make Directions request in Maps in the documentation.

Here is one tutorial on using the API.