Can not Generate Signed .apk Using Android Studio

Question

I am trying to export a Signed APK to submit to the play store but when I click Build->Generate Signed APK that option is grayed out and I can not select it.

Answer 1

I am finding in the latest versions of Android Studio the File > Project Structure > Project Settings > Facets path does not exist.

To reach Facets do this:

On your Project tree click on the upper most element, the Project itself. Then right mouse to expose the menu item Open Module Settings.

There you will find:

Project Structure Window with Facets

Once you are there then I was successful in enabling the "Generate Signed APK" Build Menu item by adding the facets as shown below:

Facets that worked for me building a Flutter app

My apologies for the external links to the images, I don't have enough reputation points yet.