Fatal Crash when using Unity to call startMoniting from AAR file

Question

I use the android-beacon-library-2.17.1.aar to make an Android App and detect the ibeacon's major/minor numbers. When I call beaconManager.startMonitoring(new Region("myMonitoringUniqueId", null, null, null)); the App runs well. And I make the program I design to the classes.jar file.

Now I use Unity and try to use this jar file to detect the ibeacon on my Unity Android Application. I put the classes.jar and AndroidManifest.xml in to my Unity project and try to call the beaconManager.startMonitoring(new Region("myMonitoringUniqueId", null, null, null)); the compile and Build are passed, but when I install the apk on my phone and run it, the application crash.

The Phone I use: Zenfone 7 -- Android 11
The version of Unity: Unity2019.4.31f1

The error log:

java.lang.NoSuchMethodError: No virtual method startRangingBeacons(Lorg/altbeacon/beacon/Region;)V in class Lorg/altbeacon/beacon/BeaconManager; or its super classes (declaration of 'org.altbeacon.beacon.BeaconManager' appears in /data/app/~~lOm13WWD8uZ_nbS2pIVb3A==/com.example.aartesting-LqhAFNQZtBYPkoICvZt1ig==/base.apk)

It's sorry that my English is not very well, and I afraid that I can't describe my problem clearly. If you want to know more about my problem, please let me know, I will try to make you know more about the situation I met.

Thank you!

Answer 1

I suspect the problem is caused by R8 or ProGuard settings, which obfuscate code to prevent reverse engineering. Aggressive R8 or ProGuard settings will rename certain classes and methods (including library class methods like startRangingBeacons mentioned in the stack trace).

You can read more about how R8 and ProGuard work here: https://developer.android.com/studio/build/shrink-code

To confirm this is the problem, you should edit your project settings for Android to disable R8 and ProGuard. Doing so for a native Android project is as simple as editing the build.gradle file and setting minifyEnabled false. Since I am not a Unity expert, I cannot tell you how to do the same thing from Unity.