Please download a new SDK for Eclipse,Android Studio use another.
Hope to help you!
See Eclipse: Failed to get the required ADT version number from the SDK
Download Old Version SDK
- https://dl.google.com/android/installer_r24.4.1-windows.exe
- https://dl.google.com/android/android-sdk_r24.4.1-windows.zip
- https://dl.google.com/android/android-sdk_r24.4.1-macosx.zip
- https://dl.google.com/android/android-sdk_r24.4.1-linux.tgz