我想使用android包安装最新的构建工具。尝试列出Android SDK包时：
$ android list sdk
Refresh Sources:
Fetching https://dl.google.com/android/repository/addons_list-2.xml
Failed to fetch URL https://dl.google.com/android/repository/addons_list-2.xml, reason: File not found
Fetched Add-ons List successfully
Refresh Sources
Fetching URL: https://dl.google.com/android/repository/repository-11.xml
Failed to fetch URL https://dl.google.com/android/repository/repository-11.xml, reason: File not found
Refresh Sources:
Fetching URL: https://dl.google.com/android/repository/repository-11.xml
Failed to fetch URL https://dl.google.com/android/repository/repository-11.xml, reason: File not found
Refresh Sources:
Fetching URL: https://dl.google.com/android/repository/repository-11.xml
Failed to fetch URL https://dl.google.com/android/repository/repository-11.xml, reason: File not found
Packages available for installation or update: 0
似乎我需要更新来源。我怎么能这样做？