android {
    buildTypes {
        debug {
          // Disable fabric build ID generation for debug builds
          ext.enableCrashlytics = false
          ...

// Set up Crashlytics, disabled for debug builds
Crashlytics crashlyticsKit = new Crashlytics.Builder()
    .core(new CrashlyticsCore.Builder().disabled(BuildConfig.DEBUG).build())
    .build();

// Initialize Fabric with the debug-disabled crashlytics.
Fabric.with(this, crashlyticsKit);