I am trying to convert Flowable<List<TaskEntity>> to Flowable<List<Task>> but something is wrong. To understand the problem I tried with converting a simpler list and it is working fine. When I try to apply the same logic to my actual problem, it is not working.
This logic is giving me expected output. [No.1 No.2 No.3]
Flowable.fromArray(Arrays.asList(1,2,3))
.flatMapIterable(ids->ids)
.map(s->"No. "+s)
.toList()
.toFlowable()
.subscribe(
t -> Log.d(TAG, "getAllActiveTasks: "+t)
);
This logic is not working . It prints Nothing
mTaskDao.getAllTasks(STATE_ACTIVE)
.flatMapIterable(task -> task)
.map(Task::create)
.toList()
.toFlowable()
.subscribe(
t -> Log.d(TAG, "getAllActiveTasks: "+t)
);
Edit 1 This is how Task.create() looks like.
public static Task create(TaskEntity eTask) {
Task task = new Task(eTask.getTaskId(), eTask.getTaskTitle(), eTask.getTaskStatus());
task.mTaskDescription = eTask.getTaskDescription();
task.mCreatedAt = eTask.getCreatedAt();
task.mTaskDeadline = eTask.getTaskDeadline();
return task;
}
Solution
As mentioned in the comments, toList() can only work if emitting source has finite number of items to emit. Since Flowable from Dao method contains an infinite stream of objects, toList() was not being used correctly by me.
Checkout this comment for the exact way to solve this problem. https://stackoverflow.com/a/50318832/4989435
toList requires a finite source but getAllTasks is likely infinite, which is unfortunately quite typical from DAOs backed by Android databases. Change the getAllTasks to Single, use take(1), use timeout(), or use flatMap(Observable.fromIterable().map().toList()) instead of flatMapIterable.
I want to receive any updates made to tasks in db.
In this case, you need the latter option:
mTaskDao.getAllTasks(STATE_ACTIVE)
.flatMapSingle(task ->
Observable.fromIterable(task)
.map(Task::create)
.toList()
)
.subscribe(
t -> Log.d(TAG, "getAllActiveTasks: "+t)
);
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