首次启动Android Studio时，就出现“Unable to access Android SDK add-on list”
google被墙了啊
之后又接二连三报各种各样的连接问题，让人头大
卡死
不能忍啊，找了一个国内http的代理，又卡在下面这一步
依然卡死
因为无所不在的墙，安装Android Studio变成一件特别恶心的事情，幸运的是后来找到了两个能连上的ip，改了hosts，世界才变得安静下来。
203.208.49.161 dl.google.com
203.208.49.162 dl-ssl.google.com
接下来是选择最少的包进行安装
Get the latest SDK tools
As a minimum when setting up the Android SDK, you should download the latest tools and Android platform:
Open the Tools directory and select:
Android SDK Tools
Android SDK Platform-tools
Android SDK Build-tools (highest version)
Open the first Android X.X folder (the latest version) and select:
SDK Platform
A system image for the emulator, such as
ARM EABI v7a System Image
