CODEWITHSUNDEEP
androidkotlinkotlin-coroutines
AndrewBloom
AndrewBloom

Reputation: 2448

Using StateFlow in an Android Project

Must be a very simple solution, but... I'm using StateFlow in my android project to replace LiveData that were used as Observables in a Service. I used LiveData as observables for Room Database but the limitations regarding thread (must register observer and notify on main thread) made me switch to Flow class. Everything fitted nicely and logically, and to keep info about state, I then decided to use StateFlow.

I added

implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.7"

and 

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
    kotlinOptions.freeCompilerArgs += ["-Xopt-in=kotlin.RequiresOptIn"]
}

in my gradle file and

@OptIn(kotlinx.coroutines.ExperimentalCoroutinesApi::class)

on top of the classes that had StateFlow member types. but I get a crash when I run the project stating:

java.lang.NoClassDefFoundError: Failed resolution of: Lkotlinx/coroutines/flow/StateFlowKt; .... Caused by: java.lang.ClassNotFoundException: Didn't find class "kotlinx.coroutines.flow.StateFlowKt" on path: DexPathList[[zip file "/data/app/com.xxxxx.consumer-X46raHzqXUeRRH40JT1LUg==/base.apk"],nativeLibraryDirectories=[/data/app/com.xxxxx.consumer-X46raHzqXUeRRH40JT1LUg==/lib/arm64, /data/app/com.xxxxx.consumer-X46raHzqXUeRRH40JT1LUg==/base.apk!/lib/arm64-v8a, /system/lib64, /system/product/lib64]] ....

What steps are necessary to add StateFlow in an Android Project using Kotlin?

Thanks!

Upvotes: 4

Views: 3453

Answers (1)

CommonsWare
CommonsWare

Reputation: 1007584

You have multiple modules, and your library module using StateFlow apparently is not distributed via an artifact repository. As a result, the app module consuming that module is not getting transitive dependency data, so it has no way of knowing that your library module wants a particular version of coroutines.

IMHO, ideally, you would use an artifact repository (e.g., mavenLocal()) and have the library module use an api dependency for the coroutines library.

If you would prefer not to mess with that, any module consuming that library should also have the coroutines dependency, with a matching (or at least compatible) version.

Upvotes: 4

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