I just want to share. This is not a question because I already found the solution that works for me.
If you are using emulator and getting the following error:
unable to connect to adb daemon on port: 5037
Try:
C:\SDK\platform-tools>adb nodaemon server
This works for me as stated in this SO page:
I've been using AS for months, but since two days I get an error when I try to run my app: Unable to run 'adb': null 'C:\Users\lapof\AppData\Local\Android\Sdk\platform-tools\adb.exe start-server' ...
If this is not working, try the following under SDK\platform-tools:
adb kill-server
adb start-server