The Zong! Viewer for Android can be compiled using Android Studio.
Please have a look at the IntelliJ IDEA page to get an idea about the required IDE settings (including Lombok), since Android Studio is based on IntelliJ IDEA.
Then, import the Android project as a Gradle project by selecting the
mobile-android subdirectory as the project folder. Do not select the root folder, since Android Studio can not deal with the other projects (Java, GWT, ...).