在哪里可以找到 liveData 构建块？

Question

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

Android coroutinesplusliveData文档指出，liveData如果我们想在实时数据函数中执行异步操作，我们可以使用builder 函数

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))
    }
}

我尝试安装lifecycle-viewmodel-ktx库，但找不到这个块。

它位于哪里？

Answer 1

尝试：

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

该函数位于此处：https : //android.googlesource.com/platform/frameworks/support/+/refs/heads/androidx-master-dev/lifecycle/livedata/ktx/src/main/java/androidx/lifecycle/CoroutineLiveData .kt

并且（当前）定义为：

@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)