我想实现最后离线的方法Flow
,如果失败,首先尝试从远程源获取数据,例如改造抛出网络异常,我想使用下面的代码从本地源获取数据
return flow { emit(repository.fetchEntitiesFromRemote()) }
.map {
println(" getPostFlowOfflineLast() First map in thread: ${Thread.currentThread().name}")
val data = if (it.isEmpty()) {
repository.getPostEntitiesFromLocal()
} else {
repository.deletePostEntities()
repository.savePostEntity(it)
repository.getPostEntitiesFromLocal()
}
entityToPostMapper.map(data)
}
.catch { cause ->
println("❌ getPostFlowOfflineLast() FIRST catch with error: $cause, in thread: ${Thread.currentThread().name}")
flow { emit(repository.getPostEntitiesFromLocal()) }
}
.map { postList ->
println(" getPostFlowOfflineLast() Second map in thread: ${Thread.currentThread().name}")
ViewState<List<Post>>(
status = Status.SUCCESS,
data = postList
)
}
.catch { cause: Throwable ->
println("❌ getPostFlowOfflineLast() SECOND catch with error: $cause, in thread: ${Thread.currentThread().name}")
flow {
emit(
ViewState<List<Post>>(
Status.ERROR,
error = cause
)
)
}
}
但它被异常卡住了
I: ❌ getPostFlowOfflineLast() FIRST catch with error: java.net.UnknownHostException: Unable to resolve host "jsonplaceholder.typicode.com": No address associated with hostname, in thread: main
onResumeNext
如果存储库函数是 Observerable ,那么像 RxJava 一样拥有任何 observable 的正确实现应该是什么?
onErrorResumeNext { _: Throwable ->
Observable.just(repository.getPostEntitiesFromLocal())
}