1.在https://www.ipaddress.com/获取dl-ssl.google.com的ip地址，按下enter后得到如：74.125.237.1的IP地址
2.在 C:\Windows\System32\drivers\etc\ 路径下的hosts文件中添加 74.125.237.1 dl-ssl.google.com
3.在Android SDK Manager中点击 tools => Options··· 勾选 Force https://...sources to be fetched using http://...