Running into `Missing class org.tensorflow.lite.gpu.GpuDelegateFactory$Options` when building an APK

[dorianbrown]

I've been putting together a prototype for a tflite model, and although the app is running smoothly in the emulator, I'm running into this error message when trying to build an apk file.

ERROR: Missing classes detected while running R8. Please add the missing classes or apply additional keep rules that are generated in /home/dorian/StudioProjects/hello_world/build/app/outputs/mapping/release/missing_rules.txt.
ERROR: R8: Missing class org.tensorflow.lite.gpu.GpuDelegateFactory$Options (referenced from: void org.tensorflow.lite.gpu.GpuDelegate.<init>() and 1 other context)

FAILURE: Build failed with an exception.
...

I've tried a number of things, but so far nothing has helped. It seems to be a missing dependency, but it's unclear to me what to add. Also adding tensorflow to proguard-rules.pro didn't help either.

Anyone else ran into this and solved it?

[dorianbrown]

Of course as soon as you post an issue, you figure out the solution. Following some suggestions in this thread, adding this to android/app/build.gradle ended up solving it:

dependencies {
    implementation "org.tensorflow:tensorflow-lite-gpu-api:+"
}

Possibly a missing dependency somewhere in tflite_flutter?

[juv85]

Caveat

For production cases it is preferable to specify the version you want to work with rather than leave it on auto-pilot with "+"

Tensorflow though great is famous for having breaking changes across versions, leaving '+' means each time a build is made it should try to pick the latest version, which might end up one day breaking your workflow someday especially for CI/CD pipelines

Preferable to specify a stable version like this instead:

dependencies {
    implementation "org.tensorflow:tensorflow-lite-gpu-api:2.12.0"
}

Spending time searching the correct version match might be a pain but it will save you time in the future