我有一个房间数据库中的剧集流。我可以毫无问题地将这个流程作为实时数据进行观察。
但我也想在用户单击按钮时读取此流程中的最后一个值。我尝试使用 first() 终端流运算符,但它无法编译。你能帮忙或提出其他建议吗?
从流中读取的非编译尝试:
bd.buttonNext.setOnClickListener {
lifecycleScope.launch {
val episode: Episode? = viewModel.episodeFlow().first() <=== Compile ERROR
Snackbar.make(bd.root, "episode ${episode?.name}", Snackbar.LENGTH_SHORT).show()
}
}
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此流程来自 ROOM :
@Query("SELECT * FROM Episode WHERE id = :id")
fun getEpisode(id: Long): Flow<Episode?>
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存储库:
fun getEpisode(episodeId: Long): Flow<Episode?> = dao.getEpisode(episodeId)
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视图模型 - Id 来自 StateFlow :
fun episodeFlow(): Flow<Episode?>
= episodeIdStateFlow.flatMapLatest { episodeId ->
repository.getEpisode(episodeId)
}
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编译错误:
Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
public fun <T> Array<out …Run Code Online (Sandbox Code Playgroud)