Android Studio ' aidl is missing ' and does not recognize R files

There's been a lot of problems with Android Studio just recently. I didn't know why I couldn't build a new project yesterday, but it took a couple of days to fix it.

But again, the problem is:

On the internet to find a lot to solve, the website is as follows:

Execution failed for task ': App:compiledebugaidl ': Aidl is missing

Http://stackoverflow.com/questions/29766830/execution-failed-for-task-appcompiledebugaidl-aidl-is-missing

Still found on the StackOverflow, is really a good website.

Android Studio ' aidl is missing ' and does not recognize R files