when I open ADT (eclipse IDE) today, it popups a window and ask for updating ADT to 22.6+ which required by a SDK and i am currently under 22.3
So i updated it following by the instruction.
However, when I reopen my ADT, I got all android projects error. Even, I am not able to create a new android project.
I have restart my ADT several times but no help.
Finally, I found this:
install all plugin in https://dl-ssl.google.com/android/eclipse/ and restart ADT.
all errors gone.