公司使用代理上网，proxy不支持git，尝试了很多办法，最后成功。
方法如下：

1 安装Android build环境需要的工具

参考source.android.com "get source"

2 Installing Repo

1. Make sure you have a~/bindirectory in your home directory, and check to be sure that this bin directory is in your path:
   $ cd ~
   $ mkdir bin
   $ echo $PATH
   
2. Download there poscript. and make sure it is executable:
   $ export http_proxy=http://your.proxy:8080
   $ curl http://android.git.kernel.org/repo >~/bin/repo
   $ chmod a+x ~/bin/repo
   $ 修改repo文件
   REPO_URL='git://android.git.kernel.org/tools/repo.git' 改成
   REPO_URL='http://android.git.kernel.org/tools/repo.git'
   

Initializing a Repo client

1. Create an empty directory to hold your working files:
   $ mkdir mydroid
   $ cd mydroid
   
2. Run "repo init" to bring down the latest version of Repo with all its most recent bug fixes. You must specify a URL for the manifest:
   $ repo init -u  http://android.git.kernel.org/platform/manifest.git
• If you would like to check out a branch other than "master", specify it with -b, like:
  $ repo init -u git://android.git.kernel.org/platform/manifest.git -b froyo
  
3. When prompted, configure Repo with your real name and email address. If you plan to submit code, use an email address that is associated with a Google account .

注意上面红色字体标注（git修改为http)

repo init成功之后，
打开 .repo\repo\project.py 修改_InitRemote函数
  def _InitRemote(self):
    if self.remote.url:
      remote = self.GetRemote(self.remote.name)
      #remote.url = self.remote.url
      # use http instead
      remote.url = self.remote.url.replace("git://", "http://")
      remote.review = self.remote.review
      remote.projectname = self.name

      if self.worktree:
        remote.ResetFetch(mirror=False)
      else:
        remote.ResetFetch(mirror=True)
      remote.Save()
然后执行
repo sync

(代理下载，下载一些大文件时，链接可能死掉，CTRL+C
再执行repo sync即可)

hope it may be helpful