Switch to a specific version of Android source code

I'm playing with the Android source开发者_Python百科 code and I would like to switch to 2.3.3 and make some modifications from there. How do I do this?

More specifically, I made a git clone of the Launcher2 project and would like to switch it to the android-2.3.3_r1a tag. I tried,

git checkout android-2.3.3_r1a

but Git seems to think I'm trying to make a new branch instead.

I also tried

git branch -r

which listed

  origin/HEAD -> origin/master
  origin/eclair
  origin/eclair-passion-release
  origin/eclair-release
  origin/eclair-sholes-release
  origin/eclair-sholes-release2
  origin/froyo
  origin/froyo-plus-aosp
  origin/froyo-release
  origin/gingerbread
  origin/gingerbread-release
  origin/master
  origin/tools_r7
  origin/tools_r8
  origin/tools_r9

and then

git checkout origin/froyo

but nothing seems to happen (files are unchanged) and

git branch

still outputs "* (no branch)".

all you need to do is git checkout -t origin/android-2.3.3_r1a. This will give you the branch you want and track the remote one.

Try:

git checkout -b android-2.3.3_r1a origin/android-2.3.3_r1a

Or:

git branch android-2.3.3_r1a origin/android-2.3.3_r1a
git checkout android-2.3.3_r1a