Because under normal circumstances is difficult to directly access the Android mainland official website, hereby lists the SDK version of Android direct download.
ADT
https://dl.google.com/android/ADT-23.0.7.zip
https://dl.google.com/android/ADT-23.0.6.zip
http://dl.google.com/android/ADT-23.0.4.zip
http://dl.google.com/android/ADT-23.0.3.zip
http://dl.google.com/android/ADT-23.0.2.zip
http://dl.google.com/android/ADT-23.0.0.zip
http://dl.google.com/android/ADT-22.6.3.zip
http://dl.google.com/android/ADT-22.6.2.zip
http://dl.google.com/android/ADT-22.6.1.zip
http://dl.google.com/android/ADT-22.6.0.zip
http://dl.google.com/android/ADT-22.3.0.zip
http://dl.google.com/android/ADT-22.2.1.zip
http://dl.google.com/android/ADT-22.2.0.zip
http://dl.google.com/android/ADT-22.0.5.zip
http://dl.google.com/android/ADT-22.0.4.zip
http://dl.google.com/android/ADT-22.0.1.zip
http://dl.google.com/android/ADT-22.0.0.zip
http://dl.google.com/android/ADT-21.1.0.zip
http://dl.google.com/android/ADT-21.0.1.zip
http://dl.google.com/android/ADT-21.0.0.zip
http://dl.google.com/android/ADT-20.0.3.zip
http://dl.google.com/android/ADT-20.0.2.zip
http://dl.google.com/android/ADT-20.0.1.zip
http://dl.google.com/android/ADT-20.0.0.zip
http://dl.google.com/android/ADT-18.0.0.zip
http://dl.google.com/android/ADT-17.0.0.zip
http://dl.google.com/android/ADT-16.0.1.zip
SDK——23.0.2
Windows32 & 64-bit:http://dl.google.com/android/android-sdk_r23.0.2-windows.zip
Windows32 & 64-bit:http://dl.google.com/android/installer_r23.0.2-windows.exe
Mac OS X32 & 64-bit:http://dl.google.com/android/android-sdk_r23.0.2-macosx.zip
Linux32 & 64-bit:http://dl.google.com/android/android-sdk_r23.0.2-linux.tgz
SDK——24.1.2
Windows32 & 64-bit:http://dl.google.com/android/android-sdk_r24.1.2-windows.zip
Windows32 & 64-bit:http://dl.google.com/android/installer_r24.1.2-windows.exe
Mac OS X32 & 64-bit:http://dl.google.com/android/android-sdk_r24.1.2-macosx.zip
Linux32 & 64-bit:http://dl.google.com/android/android-sdk_r24.1.2-linux.tgz
Android Studio——V1.1.0
Windows32 & 64-bit(SDK Included):https://dl.google.com/dl/android/studio/install/1.1.0/android-studio-bundle-135.1740770-windows.exe
Windows32 & 64-bit(No SDK Included):https://dl.google.com/dl/android/studio/install/1.1.0/android-studio-ide-135.1740770-windows.exe
Windows32 & 64-bit:https://dl.google.com/dl/android/studio/ide-zips/1.1.0/android-studio-ide-135.1740770-windows.zip
Mac OS X32 & 64-bit:https://dl.google.com/dl/android/studio/install/1.1.0/android-studio-ide-135.1740770-mac.dmg
Linux32 & 64-bit:https://dl.google.com/dl/android/studio/ide-zips/1.1.0/android-studio-ide-135.1740770-linux.zip
ADT Bundle——23.0.2
Windows 32-bit:https://dl.google.com/android/adt/adt-bundle-windows-x86-20140702.zip
Windows 64-bit:https://dl.google.com/android/adt/adt-bundle-windows-x86_64-20140702.zip
Mac OS X 64-bit:https://dl.google.com/android/adt/adt-bundle-mac-x86_64-20140702.zip
Linux 32-bit:https://dl.google.com/android/adt/adt-bundle-linux-x86-20140702.zip
Linux 64-bit:https://dl.google.com/android/adt/adt-bundle-linux-x86_64-20140702.zip