Is there a way to read the value `versionName` from the `build.gradle` file of an Android project to use it in bash?

More precisely: How can I read this value from the file and use it in a Travis-CI script? I'll use it like

```
# ANDROID_VERSION=???
export GIT_TAG=build-$ANDROID_VERSION

```

I set up a Travis-CI like described in this post <https://stackoverflow.com/a/28230711/1700776>.

My build.gradle: <http://pastebin.com/uiJ0LCSk>