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Creating a live chart for real time ble data
Hi All, Please excuse my relatively basic question but I am new to swift programming and I am battling with a project. I currently have an app that receives data from an Arduino using ble and displays the data as an integer. I used this medium article From Arduino programming to iOS App development as a guide for most of the functionality but changed the sensor data being sent to better suit my project requirements. Based on the link above, I have all of the bluetooth handling in PeripheralUseCase.swift file and then I have the ConnectView file for the display: @ObservedObject var viewModel: ConnectViewModel @Environment(\.dismiss) var dismiss @State var isToggleOn: Bool = false @State var isPeripheralReady: Bool = false @State var lastPressure: Int = 0 var body: some View { VStack { Text(viewModel.connectedPeripheral.name ?? "Unknown") .font(.title) ZStack { CardView() VStack { Text("Surface") HStack { Button("Flats") { viewModel.flats() } .disabled(!isPeripheralReady) .buttonStyle(.borderedProminent) Button("FlatPoint") { viewModel.flatPoint() } .disabled(!isPeripheralReady) .buttonStyle(.borderedProminent) Button("Points") { viewModel.points() } .disabled(!isPeripheralReady) .buttonStyle(.borderedProminent) } } } ZStack { CardView() VStack { Text("\(lastPressure) kPa") .font(.largeTitle) HStack { Spacer() .frame(alignment: .trailing) Toggle("Notify", isOn: $isToggleOn) .disabled(!isPeripheralReady) Spacer() .frame(alignment: .trailing) } } } Spacer() .frame(maxHeight:.infinity) Button { dismiss() } label: { Text("Disconnect") .frame(maxWidth: .infinity) } .buttonStyle(.borderedProminent) .padding(.horizontal) } .onChange(of: isToggleOn) { newValue in if newValue == true { viewModel.startNotifyPressure() } else { viewModel.stopNotifyPressure() } let startTime = Date().timeIntervalSince1970 } .onReceive(viewModel.$state) { state in switch state { case .ready: isPeripheralReady = true case let .Pressure(temp): lastPressure = temp default: print("Not handled") } } } } struct PeripheralView_Previews: PreviewProvider { final class FakeUseCase: PeripheralUseCaseProtocol { var peripheral: Peripheral? var onWriteLedState: ((Bool) -> Void)? var onReadPressure: ((Int) -> Void)? var onPeripheralReady: (() -> Void)? var onError: ((Error) -> Void)? func writeLedState(isOn: String) {} func readPressure() { onReadPressure?(25) } func notifyPressure(_ isOn: Bool) {} } static var viewModel = { ConnectViewModel(useCase: FakeUseCase(), connectedPeripheral: .init(name: "iOSArduinoBoard")) }() static var previews: some View { ConnectView(viewModel: viewModel, isPeripheralReady: true) } } struct CardView: View { var body: some View { RoundedRectangle(cornerRadius: 16, style: .continuous) .shadow(color: Color(white: 0.5, opacity: 0.2), radius: 6) .foregroundColor(.init(uiColor: .secondarySystemBackground)) } } With the associated View Model: @Published var state = State.idle var useCase: PeripheralUseCaseProtocol let connectedPeripheral: Peripheral init(useCase: PeripheralUseCaseProtocol, connectedPeripheral: Peripheral) { self.useCase = useCase self.useCase.peripheral = connectedPeripheral self.connectedPeripheral = connectedPeripheral self.setCallbacks() } private func setCallbacks() { useCase.onPeripheralReady = { [weak self] in self?.state = .ready } useCase.onReadPressure = { [weak self] value in self?.state = .Pressure(value) } useCase.onWriteLedState = { [weak self] value in self?.state = .ledState(value) } useCase.onError = { error in print("Error \(error)") } } func startNotifyPressure() { useCase.notifyPressure(true) } func stopNotifyPressure() { useCase.notifyPressure(false) } func readPressure() { useCase.readPressure() } func flats() { useCase.writeLedState(isOn: "1") } func flatPoint() { useCase.writeLedState(isOn: "2") } func points() { useCase.writeLedState(isOn: "3") } } extension ConnectViewModel { enum State { case idle case ready case Pressure(Int) case ledState(Bool) } } What I am now trying to do is plot the data that is received from the Arduino in a line graph as it is received. Preferably the graph will scroll with time as well.
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Mar ’24