Android SDK下载和更新失败的解决方法
最近刚换了电脑，开始搭建Android开发环境的时候，下载SDK总是会出现如下错误：
1.Failed to fetch URL http://dl-ssl.google.com/Android/repository/addons_list-1.xml.
据说dl-ssl.google.com在大陆被强了，伟大的天朝真是不让人活了，解决方法就是修改C:\Windows\System32\drivers\etc\hosts文件。添加一行：
1.74.125.237.1 dl-ssl.google.com
这里需要注意的是hosts文件是只读的，我们没有权限修改，需要我们将hosts文件复制到桌面或者其他地方，然后修改，代码如下：
1.# Copyright (c) 1993-2009 Microsoft Corp.
2.#
3.# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
4.#
5.# This file contains the mappings of IP addresses to host names. Each
6.# entry should be kept on an individual line. The IP address should
7.# be placed in the first column followed by the corresponding host name.
8.# The IP address and the host name should be separated by at least one
9.# space.
10.#
11.# Additionally, comments (such as these) may be inserted on individual
12.# lines or following the machine name denoted by a '#' symbol.
13.#
14.# For example:
15.#
16.# 102.54.94.97 rhino.acme.com # source server
17.# 38.25.63.10 x.acme.com # x client host
18.
19.# localhost name resolution is handled within DNS itself.
20.# 127.0.0.1 localhost
21.# ::1 localhost
22.//亲，就是增加这一句哦
23.74.125.237.1 dl-ssl.google.com
然后保存，复制修改后的hosts文件到C:\Windows\System32\drivers\etc 目录，替换文件就好！！！我们再次下载SDK的时候就会成功啦，如下图：
嘿嘿，大功告成啦！！！
PS：补充下，在mac或Linux中，hosts文件所在位置为/etc/hosts，可以使用sudo vim /etc/hosts来编辑。