If I follow this steps to create a new app:
Rubens-MacBook-Pro:~ rlopez$ npm install -g cordova ionic
Rubens-MacBook-Pro:~ rlopez$ ionic start myApp tabs
Rubens-
it is a permission issue chmod cmd will help you
step 1: use cmd sudo cordova run android --verbose
step 2: find below line it may vary on your install location:
/Applications/Android Studio.app/Contents/gradle/gradle-4.1/bin/gradle
step 3: run cmd with your location
sudo chmod -R 777 /Applications/Android\ Studio.app
step 4: run cmd cordova build android