转自http://my.oschina.net/jerikc/blog/77406
在www.android.com下载最新版的android-sdk_r20.0.3-windows之后，点击SDK Manager.exe，发现无法显示Updates/New的内容，因此无法进行更新。
（1）菜单Tools-->options中的Force https://...sources to be fetched using http://...勾选上。
（2）在C:\WINDOWS\system32\drivers\etc目录下，找到hosts文件，在文件末尾加上
74.125.237.1 dl-ssl.google.com
如下：
01 |
# Copyright (c) 1993-1999 Microsoft Corp. |
03 |
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows. |
05 |
# This file contains the mappings of IP addresses to host names. Each |
06 |
# entry should be kept on an individual line. The IP address should |
07 |
# be placed in the first column followed by the corresponding host name. |
08 |
# The IP address and the host name should be separated by at least one |
11 |
# Additionally, comments (such as these) may be inserted on individual |
12 |
# lines or following the machine name denoted by a '#' symbol. |
16 |
# 102.54.94.97 rhino.acme.com # source server |
17 |
# 38.25.63.10 x.acme.com # x client host |
20 |
74.125.237.1 dl-ssl.google.com |