1. open terminal
2. go to project directory
3. run – npm update
   1. to make sure all components imported added first
4. run – ionic build
   1. this will build files in web directory (normally www)
5. run – ionic cap add android
   1. android directory will be created in ionic project
6. run – “ionic cap copy android” to copy to android native project. this to run everytime you run “ionic build” to copy latest files to native android project
7. run – ionic cap open android
   1. will open android studio
   2. this will take quite some time for android to build
8. in android studio. Go to Build > Build Bundle(s)/APK
9. APK willl be generated. Click on Locate to show the apk file

Optional

1. optional – run – ionic cap sync – if you download any plugin to be used in the app

Other notes

1. I faced issue the “Build Bundle(s)/APK(s)” and “Generate signed Bundle/APK” did not appear in the menu.
2. To settle this issue, go to Android Studio > Preferences > Appearance and Behavior > System Settings > Android SDK. Choose SDK Tools tab. Tick on SDK Build-Tools and Android SDK Command-line Tools. Then click Apply. Agree to the terms and proceed.

Reference:

1. https://ionicframework.com/docs/angular/your-first-app/6-deploying-mobile
2. https://ionicframework.com/docs/developing/android