I have such code as below. How can I achieve it in one chain, without using subscribe on timer? I would like to attach 'timerInterval' to 'timer' and then call subscribe.
var timerInterval: BehaviorRelay<String> = BehaviorRelay(value: "")
...
func doLogic() {
let timer = Observable<Int>.interval(0.05, scheduler: MainScheduler.instance)
timer.subscribe({ [weak self] value in
let doubleValue = Double(value.element ?? 0)
let dividedValue = doubleValue / 20.0
let text = String(format: "%.2f", dividedValue)
self?.timerInterval.accept(text)
}).disposed(by: disposeBag)
}
You'd go for map operator. I'm not sure why you need BehaviourRelay but I'd do something even more simpler:
let timer = Observable<Int>.interval(0.05, scheduler: MainScheduler.instance)
var timerInterval: Observable<String> {
return timer.map { value -> String in
let doubleValue = Double(value.element ?? 0)
let dividedValue = doubleValue / 20.0
let text = String(format: "%.2f", dividedValue)
return text
}
}
Related
I'm trying to build a timer that starts at 15 seconds and count down until 0.
The thing is that I'll want to update that timer by 2 seconds more based on an event.
This is what I've tried to do so far:
struct ViewModel {
struct Input {
let add_time: Observable<Void>
}
struct Output {
let current_time: Observable<String>
let timer_over: Observable<Void>
}
private let current_time = BehaviorRelay(value: 15)
private let timer_over = PublishSubject<Void>()
func transform(input: Input) -> Output {
let current_time = self.current_time
.flatMapLatest { time in
Observable<Int>
.timer(.seconds(0), period: .seconds(1), scheduler: MainScheduler.instance)
.take(self.current_time.value + 1)
.map { "\(self.current_time.value - $0)" }
.do(onCompleted: { self.timer_over.onNext(()) })
}
return Output(
current_time: current_time,
timer_over: timer_over
)
}
}
let disposeBag = DisposeBag()
let add_time_subject = PublishSubject<Void>()
let input = ViewModel.Input(
add_time: add_time_subject.asObservable()
)
let output = ViewModel().transform(input: input)
output.current_time
.subscribe(onNext: { (time) in
print(time)
})
.disposed(by: disposeBag)
output.timer_over
.subscribe(onNext: {
print("timer_over")
})
.disposed(by: disposeBag)
The thing is when I run add_time_subject.onNext(()) I'd want to update the timer by 2 seconds more only if the timer hasn't reached 0 seconds.
How should I do that?
What you're trying to achieve kinda sounds like a state machine.
You could achieve it by splitting the timer actions into actual "Actions" and merging them based on the trigger (one being the manual "add two seconds", and thee other is automated as "reduce one second").
I haven't fully tested it, but this can be a good starting ground:
enum TimerAction {
case tick
case addTwoSeconds
}
let trigger = PublishRelay<Void>()
let timer = Observable<Int>
.interval(.seconds(1), scheduler: MainScheduler.instance)
.map { _ in TimerAction.tick }
let addSeconds = trigger.map { TimerAction.addTwoSeconds }
Observable
.merge(timer, addSeconds)
.scan(into: 15) { totalSeconds, action in
totalSeconds += action == .addTwoSeconds ? 2 : -1
}
.takeUntil(.inclusive) { $0 == 0 }
.subscribe()
.disposed(by: disposeBag)
DispatchQueue.main.asyncAfter(deadline: .now() + 5) {
trigger.accept(()) // increase the timer by two seconds after 5 seconds
}
The problem is described in title, but to be more specific here is a full picture.
I have a custom table view cell subclass with label inside it displaying the countdown timer. When there a small portion of timers it works fine, but with a lot of data I need to display timers far beyond the visible cells and when I scroll down fast and then scroll up fast, the timer values in cells start to show different values until a certain point in time, after which it shows the right value.
I tried different variants for those reuseable cells, but I can’t spot a problem. Help needed!!!
Here is the code of implementation of logic.
Custom cell subclass:
let calendar = Calendar.current
var timer: Timer?
var deadlineDate: Date? {
didSet {
updateTimeLabel()
}
}
override func awakeFromNib() {
purchaseCellCardView.layer.cornerRadius = 10
let selectedView = UIView(frame: CGRect.zero)
selectedView.backgroundColor = UIColor.clear
selectedBackgroundView = selectedView
}
override func prepareForReuse() {
super.prepareForReuse()
if timer != nil {
print("Invalidated!")
timer?.invalidate()
timer = nil
}
}
func configure(for purchase: Purchase) {
purchaseSubjectLabel.text = purchase.subject
startingPriceLabel.text = purchase.NMC
stageLabel.text = purchase.stage
fzImageView.image = purchase.fedLaw.contains("44") ? #imageLiteral(resourceName: "FZ44") : #imageLiteral(resourceName: "FZ223")
timeLabel.isHidden = purchase.stage == "Работа комиссии"
warningImageView.image = purchase.warningImage
}
func updateTimeLabel() {
setTimeLeft()
timer = Timer(timeInterval: 1, repeats: true) { [weak self] _ in
guard let strongSelf = self else {return}
strongSelf.setTimeLeft()
}
RunLoop.current.add(timer!, forMode: .commonModes)
}
#objc private func setTimeLeft() {
let currentDate = getCurrentLocalDate()
if deadlineDate?.compare(currentDate) == .orderedDescending {
var components = calendar.dateComponents([.day, .hour, .minute, .second], from: currentDate, to: deadlineDate!)
let dayText = (components.day! == 0 || components.day! < 0) ? "" : String(format: "%i", components.day!)
let hourText = (components.hour == 0 || components.hour! < 0) ? "" : String(format: "%i", components.hour!)
switch (dayText, hourText) {
case ("", ""):
timeLabel.text = String(format: "%02i", components.minute!) + ":" + String(format: "%02i", components.second!)
case ("", _):
timeLabel.text = hourText + " ч."
default:
timeLabel.text = dayText + " дн."
}
} else {
stageLabel.text = "Работа комиссии"
timeLabel.text = ""
timeLabel.isHidden = true
timer?.invalidate()
}
}
private func getCurrentLocalDate() -> Date {
var now = Date()
var nowComponents = calendar.dateComponents([.year, .month, .day, .hour, .minute, .second], from: now)
nowComponents.timeZone = TimeZone(abbreviation: "UTC")
now = calendar.date(from: nowComponents)!
return now
}
deinit {
print("DESTROYED")
timer?.invalidate()
timer = nil
}
The most important part of tableView(_cellForRowAt:)
case .results:
if filteredArrayOfPurchases.isEmpty {
let cell = tableView.dequeueReusableCell(
withIdentifier: TableViewCellIdentifiers.nothingFoundCell,
for: indexPath)
let label = cell.viewWithTag(110) as! UILabel
switch segmentedControl.index {
case 1:
label.text = "Нет закупок способом\n«Запрос предложений»"
case 2:
label.text = "Нет закупок способом\n«Конкурс»"
case 3:
label.text = "Нет закупок способом\n«Аукцион»"
default:
label.text = "Нет закупок способом\n«Запрос котировок»"
}
return cell
} else {
let cell = tableView.dequeueReusableCell(
withIdentifier: TableViewCellIdentifiers.purchaseCell,
for: indexPath) as! PurchaseCell
cell.containerViewTopConstraint.constant = indexPath.row == 0 ? 8.0 : 4.0
cell.containerViewBottomConstraint.constant = indexPath.row == filteredArrayOfPurchases.count - 1 ? 8.0 : 4.0
let purchase = filteredArrayOfPurchases[indexPath.row]
cell.configure(for: purchase)
if cell.timer != nil {
cell.updateTimeLabel()
} else {
search.getDeadlineDateAndTimeToApply(purchase.purchaseURL, purchase.fedLaw, purchase.stage, completion: { (date) in
cell.deadlineDate = date
})
}
return cell
}
And the last piece of a puzzle:
func getDeadlineDateAndTimeToApply(_ url: URL?, _ fedLaw: String, _ stage: String, completion: #escaping (Date) -> ()) {
var deadlineDateAndTimeToApply = Date()
guard stage != "Работа комиссии" else { return }
if let url = url {
dataTask = URLSession.shared.dataTask(with: url, completionHandler: { (data, response, error) in
if let error = error as NSError?, error.code == -403 {
// TODO: Add alert here
return
}
guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200, let data = data, let html = String(data: data, encoding: .utf8), let purchasePageBody = try? SwiftSoup.parse(html), let purchaseCard = try? purchasePageBody.select("td").array() else {return}
let mappedArray = purchaseCard.map(){String(describing: $0)}
if fedLaw.contains("44") {
guard let deadlineDateToApplyString = try? purchaseCard[(mappedArray.index(of: "<td class=\"fontBoldTextTd\">Дата и время окончания подачи заявок</td>"))! + 1].text().components(separatedBy: " ") else {return}
dateFormatter.dateFormat = "dd.MM.yyyy HH:mm"
let deadlineDateToApply = deadlineDateToApplyString.first!
let deadlineTimeToApply = deadlineDateToApplyString[1]
guard let deadlineDateAndTimeToApplyCandidate = dateFormatter.date(from: "\(deadlineDateToApply) \(deadlineTimeToApply)") else {return}
deadlineDateAndTimeToApply = deadlineDateAndTimeToApplyCandidate
} else {
guard let deadlineDateToApplyString = try? purchaseCard[(mappedArray.index(of: "<td>Дата и время окончания подачи заявок<br> (по местному времени заказчика)</td>"))! + 1].text().components(separatedBy: " ") else {return}
dateFormatter.dateFormat = "dd.MM.yyyy HH:mm"
let deadlineDateToApply = deadlineDateToApplyString.first!
let deadlineTimeToApply = deadlineDateToApplyString[2]
guard let deadlineDateAndTimeToApplyCandidate = dateFormatter.date(from: "\(deadlineDateToApply) \(deadlineTimeToApply)") else {return}
deadlineDateAndTimeToApply = deadlineDateAndTimeToApplyCandidate
}
DispatchQueue.main.async {
completion(deadlineDateAndTimeToApply)
}
})
dataTask?.resume()
}
}
A few notes:
Tried resetting deadlineDate to nil in prepareForReuse() - doesn’t help;
Using SwiftSoup Framework to parse HTML as you can see in the last code example if it matters.
This is quite a lot of code but from what you are describing your issue is in reusing cells.
You would do well to separate the timers out of the cells and put them inside your objects. It is where they belong (or in some manager like view controller). Imagine having something like the following:
class MyObject {
var timeLeft: TimeInterval = 0.0 {
didSet {
if timeLeft > 0.0 && timer == nil {
timer = Timer.scheduled...
} else if timeLeft <= 0.0, let timer = timer {
timer.invalidate()
self.timer = nil
}
delegate?.myObject(self, updatedTimeLeft: timeLeft)
}
}
weak var delegate: MyObjectDelegate?
private var timer: Timer?
}
Now all you need is is a cell for row at index path to assign your object: cell.myObject = myObjects[indexPath.row].
And your cell would do something like:
var myObject: MyObject? {
didSet {
if oldValue.delegate == self {
oldValue.delegate = nil // detach from previous item
}
myObject.delegate = self
refreshUI()
}
}
func myObject(_ sender: MyObject, updatedTimeLeft timeLeft: TimeInterval) {
refreshUI()
}
I believe the rest should be pretty much straight forward...
Your problem is here:
search.getDeadlineDateAndTimeToApply(purchase.purchaseURL,
purchase.fedLaw,
purchase.stage,
completion: { (date) in
cell.deadlineDate = date
})
getDeadlineDateAndTimeToApply runs asynchronously, calculates something, and then updates the cell.deadlineData in the main thread (which is fine). But in the meantime, while calculating something, the user might have scrolled up and down, the cell might have been reused for another row, and now the update updates the cell incorrectly.
What you need to do is: Do not store the UITableViewCell directly. Instead, keep track of the IndexPath to be updated, and once the caluclation is done, retrieve the the cell that belongs to that IndexPath and update this.
var val = 1240;
convert into little endian formate swift 3
Ex: 1500 (0x5DC) to 0xDC050000
let value = UInt16(bigEndian: 1500)
print(String(format:"%04X", value.bigEndian)) //05DC
print(String(format:"%04X", value.littleEndian)) //DC05
Make sure you are actually using the bigEndian initializer.
With 32-bit integers:
let value = UInt32(bigEndian: 1500)
print(String(format:"%08X", value.bigEndian)) //000005DC
print(String(format:"%08X", value.littleEndian)) //DC050000
If you want 1500 as an array of bytes in little-endian order:
var value = UInt32(littleEndian: 1500)
let array = withUnsafeBytes(of: &value) { Array($0) }
If you want that as a Data:
let data = Data(array)
Or, if you really wanted that as a hex string:
let string = array.map { String(format: "%02x", $0) }.joined()
let timeDevide = self.setmiliSecond/100
var newTime = UInt32(littleEndian: timeDevide)
let arrayTime = withUnsafeBytes(of: &newTime)
{Array($0)}
let timeDelayValue = [0x0B] + arrayTime
You can do something like
//: Playground - noun: a place where people can play
import UIKit
extension String {
func hexadecimal() -> Data? {
var data = Data(capacity: count / 2)
let regex = try! NSRegularExpression(pattern: "[0-9a-f]{1,2}", options: .caseInsensitive)
regex.enumerateMatches(in: self, range: NSRange(location: 0, length: utf16.count)) { match, _, _ in
let byteString = (self as NSString).substring(with: match!.range)
var num = UInt8(byteString, radix: 16)!
data.append(&num, count: 1)
}
guard !data.isEmpty else { return nil }
return data
}
}
func convertInputValue<T: FixedWidthInteger>(_ inputValue: Data) -> T where T: CVarArg {
let stride = MemoryLayout<T>.stride
assert(inputValue.count % (stride / 2) == 0, "invalid pack size")
let fwInt = T.init(littleEndian: inputValue.withUnsafeBytes { $0.pointee })
let valuefwInt = String(format: "%0\(stride)x", fwInt).capitalized
print(valuefwInt)
return fwInt
}
var inputString = "479F"
var inputValue: Data! = inputString.hexadecimal()
let val: UInt16 = convertInputValue(inputValue) //9F47
inputString = "479F8253"
inputValue = inputString.hexadecimal()
let val2: UInt32 = convertInputValue(inputValue) //53829F47
I am trying to make the enemy in my game move using DispatchQueue. I tried fixing this error and it keeps telling me attributes do not match any available overloads.
func makeAIMove() {
let strategistTime = CFAbsoluteTimeGetCurrent()
DispatchQueue.global(attributes: .qosUserInitiated).async { [unowned self] in
guard let move = self.strategist.bestMoveForActivePlayer() as? Move else { return }
let delta = CFAbsoluteTimeGetCurrent() - strategistTime
DispatchQueue.main.async{ [unowned self] in
self.rows[move.row][move.col].setPlayer(.choose)
let aiTimeCeiling = 2.0
let delay = min(aiTimeCeiling - delta, aiTimeCeiling)
DispatchQueue.main.after(when: .now() + delay) { [unowned self] in
self.makeMove(row: move.row, col: move.col)
}
}
}
}
I think what you want is DispatchQueue.global(qos: .userInitiated); indeed, there is no overload taking an attributes argument.
I'm trying to retrieve the temperature from the users current location.
I am using the API from OpenWeatherMap. The problem is, they provide the temperature in Kelvin as default, and I would like it in Celsius.
I understand that I just need to subtract 273.15 from the kelvin value....? But i'm struggling to figure out where to do that.
My code for setting my labels:
var jsonData: AnyObject?
func setLabels(weatherData: NSData) {
do {
self.jsonData = try NSJSONSerialization.JSONObjectWithData(weatherData, options: []) as! NSDictionary
} catch {
//handle error here
}
if let name = jsonData!["name"] as? String {
locationLabel.text = "using your current location, \(name)"
}
if let main = jsonData!["main"] as? NSDictionary {
if let temperature = main["temp"] as? Double {
self.tempLabel.text = String(format: "%.0f", temperature)
}
}
}
Can anyone help me get this right please, as I'm really not sure where to start, thanks.
Let me know if you need to see more of my code.
if let kelvinTemp = main["temp"] as? Double {
let celsiusTemp = kelvinTemp - 273.15
self.tempLabel.text = String(format: "%.0f", celsiusTemp)
}
or simply
self.tempLabel.text = String(format: "%.0f", temperature - 273.15)
For Swift 4.2:
Use a Measurement Formatter.
let mf = MeasurementFormatter()
This method converts one temperature type (Kelvin, Celsius, Fahrenheit) to another:
func convertTemp(temp: Double, from inputTempType: UnitTemperature, to outputTempType: UnitTemperature) -> String {
mf.numberFormatter.maximumFractionDigits = 0
mf.unitOptions = .providedUnit
let input = Measurement(value: temp, unit: inputTempType)
let output = input.converted(to: outputTempType)
return mf.string(from: output)
}
Usage:
let temperature = 291.0
let celsius = convertTemp(temp: temperature, from: .kelvin, to: .celsius) // 18°C
let fahrenheit = convertTemp(temp: temperature, from: .kelvin, to: .fahrenheit) // 64°F
To output the localized temperature format, remove the line mf.unitOptions = .providedUnit
From the code above, it seems to me the right place to do this would be right after you get the temperature
if let temperatureInKelvin = main["temp"] as? Double {
let temperatureInCelsius = temperatureInKelvin - 273.15
self.tempLabel.text = String(format: "%.0f", temperature)
}
In the future though, I would probably parse your JSON values in a separate class and store them in a model object which you can call later on.
A simpler example of the above handy function (updated for Swift 5.3) would be something like:
func convertTemperature(temp: Double, from inputTempType: UnitTemperature, to outputTempType: UnitTemperature) -> Double {
let input = Measurement(value: temp, unit: inputTempType)
let output = input.converted(to: outputTempType)
return output.value
}
Here:
self.tempLabel.text = String(format: "%.0f", temperature - 273.15)
or you can do it here (pseudo syntax as I don't know Swift that well):
if let temperature = (main["temp"] as? Double) - 273.15 {
self.tempLabel.text = String(format: "%.0f", temperature)
}