Where to find the liveData building block?

Question

https://developer.android.com/topic/libraries/architecture/coroutines

Android coroutines plus liveData documentation states that we can use the liveData builder function in case we want to want to perform async operations inside the live data function

val user: LiveData<User> = liveData {
    val data = database.loadUser() // loadUser is a suspend function.
    emit(data)
}

val user: LiveData<Result> = liveData {
    emit(Result.loading())
    try {
        emit(Result.success(fetchUser())
    } catch(ioException: Exception) {
        emit(Result.error(ioException))
    }
}

I tried installing the lifecycle-viewmodel-ktx library but couldn't find this block.

Where is it located?

Answer 1

Try:

implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.2.0-alpha01'

The function lives here: https://android.googlesource.com/platform/frameworks/support/+/refs/heads/androidx-master-dev/lifecycle/livedata/ktx/src/main/java/androidx/lifecycle/CoroutineLiveData.kt

And is (currently) defined as:

@UseExperimental(ExperimentalTypeInference::class)
fun <T> liveData(
    context: CoroutineContext = EmptyCoroutineContext,
    timeoutInMs: Long = DEFAULT_TIMEOUT,
    @BuilderInference block: suspend LiveDataScope<T>.() -> Unit
): LiveData<T> = CoroutineLiveData(context, timeoutInMs, block)