IntelliJ IDEA "cannot resolve symbol" and "cannot resolve method"
Most likely JDK configuration is not valid, try to remove and add the JDK again as I've described in the related question here.
First check if you have configured JDK correctly:
- Go to File->Project Structure -> SDKs
- your JDK home path should be something like this: /Library/Java/JavaVirtualMachine/jdk.1.7.0_79.jdk/Contents/Home
- Hit Apply and then OK
Secondly check if you have provided in path in Library's section
- Go to File->Project Structure -> Libraries
- Hit the + button
- Add the path to your src folder
- Hit Apply and then OK
This should fix the problem