java 从 Flowable 一次发出一个列表项
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Emit one List item at a time from a Flowable
提问by Orbit
I have a method which returns a Flowable<RealmResults<MyClass>>. For those not familiar with Realm, RealmResultsis just a simple Listof items.
我有一个方法返回一个Flowable<RealmResults<MyClass>>. 对于那些不熟悉 Realm 的人来说，RealmResults只是一个简单List的项目。
Given a Flowable<RealmResults<MyClass>>, I'd like to emit each MyClassitem so that I can perform a map()operation on each item.
给定 a Flowable<RealmResults<MyClass>>，我想发出每个MyClass项目，以便我可以map()对每个项目执行操作。
I am looking for something like the following:
我正在寻找类似以下内容：
getItems() // returns a Flowable<RealmResults<MyClass>>
.emitOneAtATime() // Example operator
.map(obj -> obj + "")
// etc
What operator will emit each List item sequentially?
哪个运算符将按顺序发出每个 List 项？
回答by Adam Dye
You would flatMap(aList -> Flowable.fromIterable(aList)). Then you can map()on each individual item. There is toList()if you want to recollect the items (note: this would be a new List instance). Here's an example illustrating how you can use these methods to get the different types using List<Integer>.
你会的flatMap(aList -> Flowable.fromIterable(aList))。然后你可以map()在每个单独的项目上。还有toList()，如果你想回忆的物品（注：这将是一个新的List实例）。这是一个示例，说明如何使用这些方法使用List<Integer>.
List<Integer> integerList = new ArrayList<>();
Flowable<Integer> intergerListFlowable =
Flowable
.just(integerList)//emits the list
.flatMap(list -> Flowable.fromIterable(list))//emits one by one
.map(integer -> integer + 1);
回答by Tassos Bassoukos
The question is, do you want to keep the results as a Flowable<List<MyClass>>or as a Flowable<MyClass>with retained order?
问题是，您希望将结果保留为保留顺序Flowable<List<MyClass>>还是Flowable<MyClass>保留顺序？
If the first,
如果第一个，
getItems()
.concatMap(results -> Flowable
.fromIterable(results)
.map(/* do your mapping */)
.toList()
)
If the second, this should suffice:
如果是第二个，这应该就足够了：
getItems()
.concatMap(Flowable::fromIterable)
.map(/* do your mapping */)
