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-         
        
Running ionic build android --verbose gives the following output:
/Applications/Android Studio 2.4 
Preview.app/Contents/gradle/gradle-3.4.1/bin/gradle -p 
/Users/rlopez/myApp/platforms/android wrapper -b 
/Users/rlopez/myApp/platforms/android/wrapper.gradle
Error: spawn EACCES
    at exports._errnoException (util.js:1018:11)
    at ChildProcess.spawn (internal/child_process.js:319:11)
    at Object.exports.spawn (child_process.js:378:9)
    at exports.spawn(/Users/rlopez/myApp/platforms/android/cordova/node_modules/cordova-common/src/superspawn.js:134:31)
    at GradleBuilder.runGradleWrapper(/Users/rlopez/myApp/platforms/android/cordova/lib/builders/GradleBuilder.js:78:14)
    at /Users/rlopez/myApp/platforms/android/cordova/lib/builders/GradleBuilder.js:178:21
    at _fulfilled (/Users/rlopez/myApp/platforms/android/cordova/node_modules/q/q.js:854:54)
    at self.promiseDispatch.done (/Users/rlopez/myApp/platforms/android/cordova/node_modules/q/q.js:883:30)
    at Promise.promise.promiseDispatch (/Users/rlopez/myApp/platforms/android/cordova/node_modules/q/q.js:816:13)
    at /Users/rlopez/myApp/platforms/android/cordova/node_modules/q/q.js:570:49
Changing the permissions of /Applications/Android Studio 2.4 Preview.app/Contents/gradle/gradle-3.4.1/bin/gradle solves the problem.