I just updated my Android SDK Tools to version 21.1. Unfortunately this is causing an error when I load the Android Developer Toolkit:
The Android SDK requires Android Developer Toolkit version 21.1.0 or above.
Current version is 21.0.1.2012-12-6-2-58.
Please update ADT to the latest version.
When I upgraded the SDK I was warned that I might need to upgrade ADT. I tried to do so by going to Help > Check for Updates. Unfortunately this returns a message that "No updates were found."
In case I've missed something here's a screenshot of my Android SDK Manager:
Am I missing an install package? Do I need to go about updating ADT (Eclipse) another way? Should I just download a new copy of ADT?
For some reason ADT (Eclipse) won't pick up on the fact that it does in fact need to be updated. Since the built in tools for updating are failing you you'll have to work around them. On the Help menu instead of selecting Check for Updates instead pick Install New Software (so Help > Install New Software).
On the Available Software screen in the Work With dropdown provide:
https://dl-ssl.google.com/android/eclipse/ if it's not already available. You should see a list of options including Developer Tools. Check everything that you want to update. In the list of checkboxes below uncheck "Contact all update sites during install to find required software."
Click Next and follow the remaining onscreen prompts. You may be warned that instead of an install an update will be performed. This is okay. Once the operation is complete you will no longer receive the "The Android SDK requires Android Developer Toolkit verxion 21.1.0 or above" error when you load ADT.
来源：https://stackoverflow.com/questions/15105730/when-i-load-adt-why-do-i-receive-the-error-the-android-sdk-requires-android-dev