If you have tried all of these and they did not work out. There is a problem with the current version of android studio configuration file that you are using. Please try this solution. Follow this.

1. Find the configuration file by entering the path

/Users/xxxxx(your username)/Library/Application Support/Google.

1. Find the current version of the as configuration file
2. Delete the file or folder.
3. Reopen Android Studio and follow the instructions to install all the SDKs, Emulator and all that. just like the first time you installed it.

I hope this resolves your problem.