bluetooth - SwiftUI: Function for writing characteristic to BLE Peripheral using data from different views

Question

I am building an app in SwiftUI that communicates over BLE with a custom device that has an LED ring light. I can't figure out how to code the write functions correctly using data/variables from other views.

On ringLight.swift I have a color wheel with rgbColour variable which consists of three floats for the rgb values. I also have a toggle that when tapped should do two things (turn the light on):

1. Write the rbgColour variable (3 floats) to the RGBCharacteristicUUID
2. Send the integer 1 to the ConfigCharacteristicUUID to turn the light on.

I am attempting to keep the UI views containing the characteristic's data separate from the BLEManager. Any insight on how to properly structure this/ how to do the write function? Thanks!!

ringLight.swift

struct ringLight: View {
    
    @State var rgbColour = RGB(r: 0, g: 1, b: 1)
    @State var brightness: CGFloat = 1
    @State var turnHubLEDON = false
    @ObservedObject var bleManager = BLEManager()
   
    
    var body: some View {
       
            VStack {

                /// The text at the top.
                HStack {
                    Text("Choose your hub color")
                        .font(.largeTitle)
                        .fontWeight(.light)
                        .padding(.bottom, 50)
                
                }
                
                /// The actual colour wheel.
                ColourWheel(radius: 300, rgbColour: $rgbColour, brightness: $brightness)
                    .padding(.bottom, 30)
                
                
                /// The slider shows the selected colour and allows control of the brightness/value. Cannot have value at 0 otherwise we lose the RGB value.
                CustomSlider(rgbColour: $rgbColour, value: $brightness, range: 0.001...1)
                    .padding()
                Text("R: (CGFloat(rgbColour.r)) G: (CGFloat(rgbColour.g)) B: (CGFloat(rgbColour.b))")
                
                VStack{
                    Toggle("Light", isOn: $turnHubLEDON).labelsHidden().padding()
                    
                    if turnHubLEDON {
                    
                        // **Function to send the rgbColour variable & Config Integer here**
                        
                        
                    }
                
                }
                
            
            } // End VStack
      }
}

BLEManager.swift (relevant parts)

class BLEManager: NSObject, ObservableObject, CBCentralManagerDelegate, CBPeripheralDelegate  {

    var myCentral: CBCentralManager!
    var myPeripheral: CBPeripheral!
    
    //LED Light
    var ConfigChar: CBCharacteristic?
    var RGBChar: CBCharacteristic?
    var BrightnessChar: CBCharacteristic?
    
    @Published var isSwitchedOn = false
    @Published var hubPeripheral = [Peripheral]()
    @Published var hubIsConnected = false
    
    override init() {
        super.init()


        myCentral = CBCentralManager(delegate: self, queue: nil)
        myCentral.delegate = self
    }

   func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
           if let characteristics = service.characteristics {
               for characteristic in characteristics {
                  
                   //LED Light
                   if characteristic.uuid == HubPeripheral.ConfigCharacteristicUUID {
                       print("LED Configuration Characteristic Found")
                       ConfigChar = characteristic
                       
                   } else if characteristic.uuid == HubPeripheral.RGBCharacteristicUUID {
                       print("LED RGB Characteristic Found")
                       RGBChar = characteristic
                       
                   } else if characteristic.uuid == HubPeripheral.BrightnessCharacteristicUUID {
                       print("LED Brightness Characteristic Found")
                       BrightnessChar = characteristic
               
               }
               
           } // End Characteristics
       } // End If statement
   } // End DidDiscoverCharacteristics
       
       
        // **How do I structure these write functions to include data from ringLight.swift?**
       func writeConfigurationValue() {
           
           var parameter = NSInteger(1)
           let data = NSData(bytes: &parameter, length: 1)
           myPeripheral.writeValue(data as Data, for: ConfigChar!, type: .withoutResponse)
             
           }
       
   } // End Delegate

Characteristics

class HubPeripheral: NSObject {
     
    
    /// MARK: - Hub LED services and characteristics
    
    public static let RingLightServiceUUID     = CBUUID.init(string: "020013ac-4202-93ae-eb11-7d58e021f8f1")
    
    public static let RGBCharacteristicUUID   = CBUUID.init(string: "fdefb439-68de-1a88-5345-5cc9f9ff5605")
    public static let BrightnessCharacteristicUUID   = CBUUID.init(string: "4960d639-1407-9cbb-6846-5360eb5e6346")
    public static let ConfigCharacteristicUUID   = CBUUID.init(string: "cc0a6373-dc51-c1af-0140-b0322225ed9b")

}

question from:https://stackoverflow.com/questions/65874309/swiftui-function-for-writing-characteristic-to-ble-peripheral-using-data-from-d

Answer 1

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