举个栗子，
手动下载sdk tools r25.2.5 mac版本：
https://dl.google.com/android/repository/tools_r25.2.5-macosx.zip
手动下载ndk r10e linux版本：
https://dl.google.com/android/repository/android-ndk-r10e-linux-x86_64.zip
Manual download
As not every package (especially the old ones) is listed when you do android sdk list, you can also download things manually. You can manually open the XML file that is shown when during android sdk list - https://dl.google.com/android/repository/repository-11.xml
You can find there links to various types of things to download, e.g:
ADT
http://dl.google.com/android/ADT-XX.0.0.zip
SDK Tools
http://dl.google.com/android/repository/tools_rXX-linux_x86.zip
http://dl.google.com/android/repository/tools_rXX-windows.zip
http://dl.google.com/android/repository/tools_rXX-macosx.zip
Platform Tools
http://dl.google.com/android/repository/platform-tools_rXX-linux_x86.zip
http://dl.google.com/android/repository/platform-tools_rXX-windows.zip
http://dl.google.com/android/repository/platform-tools_rXX-macosx.zip
Build Tools
http://dl.google.com/android/repository/build-tools_rXX-linux.zip
http://dl.google.com/android/repository/build-tools_rXX-windows.zip
http://dl.google.com/android/repository/build-tools_rXX-macosx.zip
Platforms
http://dl.google.com/android/repository/android-XX.zip
