I think the problem related to Android platform installation was caused by my old Cordova installation. There seem to be a "bug" in npm so that if I type "npm install cordova -g" it's failing silently if there is already some old Cordova installation. Mine was 3.3.1-0.1.2 from year 2013 when I made Cordova applications. That one was not npm installation. Ionic is not compatible with so old Cordova.
It's always good to check all program versions with -v before doing any other troubleshooting.
I think the problem related to Android platform installation was caused by my old Cordova installation. There seem to be a "bug" in npm so that if I type "npm install cordova -g" it's failing silently if there is already some old Cordova installation. Mine was 3.3.1-0.1.2 from year 2013 when I made Cordova applications. That one was not npm installation. Ionic is not compatible with so old Cordova. It's always good to check all program versions with -v before doing any other troubleshooting.