Continuous integration with Android [Codeship]

I have an Android app source code that uses 1 Android SDK (obviously) 2 Robolectric (for unit tests) 3 Gradle (for build process)

The problem when trying to use a different build process is that I need to go into my repo and get the Android SDK every time and extract it. Then clean and run my tests and jacocoTestReport. This takes time, not because of the number of tests, but because of the amount of time it took to fetch the Android SDK and extract. On my local machine, I can use Jenkins with an Android plugin.

My question is: Am I doing this correctly? Is there an easier way to get around this to reduce build time so that I can put the POST hook on top of my repo to make it work better (it only takes the time it takes to run tests and reports).