I have select from sqlbrite db but observable do not call onComplete for some reason.
My code:
fun BriteDatabase.selectDayTimelineRecord(dayTimestamp: Long) =
createQuery(table_timeline, selectWDayRecords(dayTimestamp)).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread())
.mapToOneOrDefault(StatItem(dayTimestamp, 0)) { cursor -> cursor.mapTimelineStat() }
and then I try variants:
working but I need to keep order so I can not use flatmap
Observable.fromIterable(0..6).flatMap{
db.selectDayTimelineRecords(timestampOfDayInWeek(it))
}.buffer(7).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe {}
not working (not delivery result but I do not know why)
Observable.fromIterable(0..6).concatMap{
db.selectDayTimelineRecords(timestampOfDayInWeek(it))
}.buffer(7).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe {}
As result I want Observable with list of T...
Anyone know what am I doing wrong?
I am not very familiar with SQLBrite but createQuery supposed to be keep notifying database changes. If you want to get value just once then you can use take() operator.
fun BriteDatabase.selectDayTimelineRecord(dayTimestamp: Long) =
createQuery(table_timeline, selectWDayRecords(dayTimestamp))
.mapToOneOrDefault(StatItem(dayTimestamp, 0)) { cursor -> cursor.mapTimelineStat() }
.take(1)
Then your concatMap implementation will work.
Related
I use a MapStateDescriptor for my stateful computation. Some code here
final val myMap = new MapStateDescriptor[String, List[String]]("myMap", classOf[String], classOf[List[String]])
During my computation i want to update my map by adding new elements to the List[String].
Is it possible?
Update #1
have written following def to manage my map
def updateTagsMapState(mapKey: String, tagId: String, mapToUpdate: MapState[String, List[String]]): Unit = {
if (mapToUpdate.contains(mapKey)) {
val mapValues: List[String] = mapToUpdate.get(mapKey)
val updatedMapValues: List[String] = tagId :: mapValues
mapToUpdate.put(mapKey, updatedMapValues)
} else {
mapToUpdate.put(mapKey,List(tagId))
}
}
Sure, it is. Depending on whether this is Scala List or Java that You will be using there you can do smth like that to actually create the state from descriptor:
lazy val stateMap = getRuntimeContext.getMapState(myMap)
Then You can simply do:
val list = stateMap.get("someKey")
stateMap.put("someKey", list +: "SomeVal")
Note that if You would work with mutable data structure, You wouldn't necessarily need to call put again, since the update of the data structure would also update the state. But this approach does not work in case of RocksDB state, since the state is only updated after You call put in this case, so it is always advised to update the state itself instead of just underlying object.
I have 2 Angular (1.6.4) components and a service. The service creates 2 observables like this (coffeescript)...
// In service constructor
#observable = Rx.Observable.create (source) =>
source.next(123)
#observable2 = Rx.Observable.create (source) =>
#observer = source
$timeout =>
#observer.next(345)
, 1000
In my controllers I have these lines
//Component 1
service.observable.subscribe (v) => console.log('consumer A1: ' + v)
service.observable2.subscribe (v) => console.log('consumer A2: ' + v)
//Component 2
service.observable.subscribe (v) => console.log('consumer B1: ' + v)
service.observable2.subscribe (v) => console.log('consumer B2: ' + v)
I would expect to see 4 console logs but instead I see 3 (A1, B1, B2). Why is it then when I call from outside only the last subscribe gets called but when it is inside both get called? Is there a way to have the second example call both (preferably as an Observable and not a Subject)?
If I do use a Subject everything works as expected but I am still curious why it doesn't work as I would expect with an observable.
Your observable2 is taking the subscriber and storing it in a variable (#observer) each time something subscribes. So the 2nd subscription (B2) is replacing the value in the variable.
It is hard to say what the correct way to rewrite the 2nd observer should be because it isn't clear what your goal is. A Subject can certainly work. Observable.timer might also work, depending on your goal.
The Observable.timer way would be:
#observable2 = Observable.timer(1000);
Anything that subscribes to that would get an event 1 second after it subscribed.
I'm trying to change the value of a global variable transferredData in the function didTransferData(_ data: Data?). My code looks like this:
var transferredData: [Double] = [0.0]
func didTransferData(_ data: Data?) {
var dataArray = [CUnsignedChar](repeating:0, count: (data?.count)!)
data?.copyBytes(to: &dataArray, count: dataArray.count)
let dataInt = dataArray.filter({ Int(String($0)) != nil }).map({ Int(String($0))! })
let dataDouble = dataInt.map { Double($0) }
print("Data double: \(dataDouble)")
transferredData = dataDouble
}
Printing transferredData inside of didTransferData returns the correct array, containing all values of dataDouble. But when I try to access it in this function later on
func returnData() -> [Double]{
print("return Data: \(transferredData)")
return transferredData
}
it returns [0.0]. I'm not sure if I'm missing something crucial here, but I thought that even if I change the value of a global variable in a function, the new value should be accessible for every other functions, too.
Thanks for any advice!!
You said that this code is inside a class. The variable transferredData is not a global, it is a member variable.
There is one of these per object of the class. I suspect that you are not using the same object to make these two calls.
You could make the member shared between all objects by declaring it static, but I think it would be better to leave as is and arrange to use the same object.
EDIT: based on comment
If you write the code
let centralInstance = CentralViewController()
You will get a new object with its own transferredData member initially set to [0.0]. You need to either
Get a reference to the same VC object that has the data
Store the data some where else in an object that you can get back (since the VC might be gone)
To hack something that works (not recommended, but to help understand)
You could move transferredData out of the class and make it an actual global variable. I would do this only to help you get past this issue and understand what's going on.
You could also make it static, which makes all of the VC's share the same instance of the transferredData
When you understand what is going on, you can try to do something a little better (at least move it to its own model object, and not in the VC at all). The next simplest thing is some kind of singleton to manage it -- this is just a glorified global variable but puts you more on the road to a more typical solution.
Where is the problem:
$ swift
Welcome to Apple Swift version 3.0.2 (swiftlang-800.0.63 clang-800.0.42.1). Type :help for assistance.
1> var data:[Double] = [0.0]
2.
3. class MuckWithData {
4.
5. func showData () -> [Double] {
6. print ("Data: \(data)")
7. return data
8. }
9.
10. func modifyData () {
11. data = [1.0]
12. }
13. }
data: [Double] = 1 value {
[0] = 0
}
14>
15> var mucked = MuckWithData()
mucked: MuckWithData = {}
16> mucked.showData()
Data: [0.0]
$R0: [Double] = 1 value {
[0] = 0
}
17> mucked.modifyData()
18> mucked.showData()
Data: [1.0]
$R1: [Double] = 1 value {
[0] = 1
}
Probably your computation for dataDouble is actually [0.0] and thus it appears that transferredData didn't change, but it did.
I have an array of Thing objects that I want to convert to ConvertedThing objects, using an asynchronous function that returns Observable<ConvertedThing>.
I'd like to create an Observable<[ConvertedThing]> that emits one value when all the conversions have completed.
How can this be accomplished? Any help much appreciated!
You can use .merge() to combine the array of observables into a single observable, and then use .toArray() to get them as a list in a single event.
For RxSwift 3+ use:
let arrayOfObservables: [Observable<E>] = ...
let singleObservable: Observable<E> = Observable.from(arrayOfObservables).merge()
let wholeSequence: Observable<[E]> = singleObservable.toArray()
For previous versions:
let arrayOfObservables: [Observable<E>] = ...
let singleObservable: Observable<E> = arrayOfObservables.toObservable().merge()
let wholeSequence: Observable<[E]> = singleObservable.toArray()
For future readers:
Using .merge() and .toArray() will emit a single element when all observable sequences complete. If any of the observables keeps emitting, it will not emit or complete.
Using .combineLatest() will return an Observable that emits the full list every time any observable changes:
let arrayOfObservables: [Observable<E>] = ...
let wholeSequence: Observable<[E]> = Observable.combineLatest(arrayOfObservables) { $0 }
I have got Dispatched events in my gideros game. What im not certain of, is that when i try access the event (object triggered) it returns a table that has a length of 0.
I have a letter class as below:
GridLetter = gideros.class(Sprite)
function GridLetter:init(letter)
self.image = Bitmap.new(Texture.new("GridLetters/"..letter.."Grid.png"))
self.image:setAnchorPoint(0.5, 0.5)
self.focus = false
self:updateVisualState(true)
self:addEventListener(Event.MOUSE_DOWN, self.onMouseDown, self)
end
function GridLetter:onMouseDown(event)
if self:hitTestPoint(event.x, event.y) then
self.focus = true
self:dispatchEvent(Event.new("GridLetterDown"))
event:stopPropagation()
end
end
function GridLetter:updateVisualState(state)
if state then
self:addChild(self.image)
end
end
The code that implements this class is below:
grid = Core.class(Sprite)
local letterArr = {"a","b","c","d","e","f","g","h","u","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"}
local gridboard = {{},{},{},{}}
local letterBoxArr = {{},{},{},{}}
local letterBox
function grid:init(params)
local widthOfSingle = (application:getContentWidth() / 4)
for rowCount = 1,4 do
for colCount = 1,4 do
rand = math.random(1, 26)
gridboard[rowCount][colCount] = letterArr[rand]
end
end
for rowCount = 1,4 do
for colCount = 1,4 do
letterBox = GridLetter.new(gridboard[rowCount][colCount])
letterBoxArr[rowCount][colCount] = {letterBoxItem=letterBox}
letterBoxArr[rowCount][colCount].letterBoxItem:setPosition(((widthOfSingle * colCount) - (widthOfSingle / 2)), 100 * rowCount)
letterBoxArr[rowCount][colCount].letterBoxItem.letter = gridboard[rowCount][colCount];
letterBoxArr[rowCount][colCount].letterBoxItem:addEventListener("GridLetterDown", LetterDown, self)
self:addChild(letterBoxArr[rowCount][colCount].letterBoxItem)
end
end
end
function LetterDown(event)
print(event.target.letter)
end
When i click on one of these image, the event is fired and code does run under the LetterDown event, but when trying to access the event parameter, it returns:
grid.lua:32: attempt to index field 'target' (a nil value)
stack traceback:
grid.lua:32: in function <grid.lua:31>
GridLetter.lua:15: in function <GridLetter.lua:12>
any idea or workarounds?
When replacing:
print(event.target.letter)
to
print(event.x)
It prints nil.
I appreciate your help in advance.
Regards,
Warren
This isn't an answer (I'd comment, but that strangely requires rep).
The error you're getting is because in event, there's nothing in the target field.
You could find out what's in the table by looping over it (or by using a pretty table print function, if glideros defines one/you define one yourself):
for k, v in pairs(target) do print(k, v) end
If you're not sure if target will exist all the time, you can also do something like this:
print(not event.target and "event.target does not exist" or event.target.letter)
You can read about the A and B or C construct here: http://lua-users.org/wiki/TernaryOperator
Edit: Assuming that the event you receive fires with a GridLetter object, you are not setting self.letter to anything. Perhaps setting the field will help:
function GridLetter:init(letter)
self.letter = letter -- Forgot this?
self.image = Bitmap.new(Texture.new("GridLetters/"..letter.."Grid.png"))
self.image:setAnchorPoint(0.5, 0.5)
self.focus = false
self:updateVisualState(true)
self:addEventListener(Event.MOUSE_DOWN, self.onMouseDown, self)
end
I have got it.. Someone on gideros forums helped me out, thanks to Advert as well.
So in my onMouseDown event i was assigning the .letter on the general event. So creating a local var and assigning it the event before dispatching it, the variable then keeps my assigned letter.
Hope this helps others in future!
function GridLetter:onMouseDown(event)
if self:hitTestPoint(event.x, event.y) then
self.focus = true
local e = Event.new("GridLetterDown")
e.letter = self.letter
self:dispatchEvent(e)
event:stopPropagation()
end
end
Thanks for all responses.