Cannot convert BLE advertisement data to String in Swift-CodePudding

I am using a standard CentralManager call to get some BLE advertisement data without connecting. My code snippet is:

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
                
        print("The value of ManufacturerData is \(String(describing: advertisementData[CBAdvertisementDataManufacturerDataKey]))")

        var manufacturerData: String!

        if let mData = advertisementData[CBAdvertisementDataManufacturerDataKey] {
            manufacturerData = String(data: mData as! Data, encoding: UTF8.self)
        }
        else {
            manufacturerData = ""
        }
....
}

The print line produces

The value of ManufacturerData is Optional(<3235343a 3834>)

which shows the 2 integer values I want as 254:84 so I know that the values are there. I can't find a way to get the manufacturerData in a form to start extracting the 2 values. The error on the 'manufacturerData =' line is

Cannot convert value of type ‘UTF8.Type’ (aka ‘Unicode.UTF8.Type’) to expected argument type ’String.Encoding’

CodePudding user response：

manufacturerData = String(data: mData as! Data, encoding: UTF8.self)

should be

manufacturerData = String(data: mData as! Data, encoding: .utf8)

Now, to avoid the force unwrap, you could do:

if let mData = advertisementData[CBAdvertisementDataManufacturerDataKey] as? Data {
    manufacturerData = String(data: mData, encoding: .utf8)
}

manufacturerData then will be "254:84"

From that, you can use components(separatedBy:):

let components = manufacturerString.components(separatedBy: ":")
let first = components[0] //"254"
let second = components[1] //"84"