Download and extract the universal GStreamer Android binaries to a directory of your choice.
https://gstreamer.freedesktop.org/data/pkg/android/
Edit gradle.properties in order to set gstAndroidRoot to point to the unpacked GStreamer Android binaries.
To build and deploy the rtsp example to your device, use a command similar to:
$ PATH=~/dev/android/tools/bin:~/dev/android/ndk-bundle:$PATH ANDROID_HOME="$HOME/dev/android/" ./gradlew installDebug
$ adb shell am start -n org.freedesktop.gstreamer.rtsp_example/.RTSPExample
To see the GStreamer logs at runtime:
$ adb logcat | egrep '(gst)'
Launch Android-studio, opening this folder as a project.
The project should build automatically, once it has done successfully, it should be possible to run the project with Run > Run 'app', provided a device is attached and USB debugging enabled.
The logs can be seen in the logcat tab.