如何向 BLE 设备写入多个命令

Question

I'm working on an app which needs to get data from BLE device to show on app. In order to get datas from BLE device I have to write certain commands like NUM_QUEUE , READ_ALL etc.

So I'm stuck here to execute all commands together; I assigned all commands into an array and execute write function on loop by fetching each commands.

But when I read value I got the value of only last command in the array.

Here is the code:

 func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {

        if let characterArray = service.characteristics as [CBCharacteristic]? {
            for cc in characterArray {
                myCharacteristic = cc 
                peripheral.readValue(for: cc) 
                peripheral.setNotifyValue(true, for: myCharacteristic)
                writeValue()
            }
        }
    }  

func writeValue() {

        if isMyPeripheralConected { //check if myPeripheral is connected to send data
            let arrayCommands = ["NUM_QUEUE\r","READ_ALL\r"]
            for i in 0...arrayCommands.count-1 {
                let dataToSend: Data = arrayCommands[i].data(using: String.Encoding.utf8)!
                myBluetoothPeripheral.writeValue(dataToSend, for: myCharacteristic, type: CBCharacteristicWriteType.withResponse)
            }
           
        } else {
            print("Not connected")
        }
        
    }

Answer 1

I would use enum for keeping all of the commands together. Like so:

enum Command: String {

case NUM_QUEUE = "..."
case READ_ALL  = "..."

This way you can also get rawValue if you need it.

Answer 2

Create an enum that has a String raw value type and follows the CaseIterable protocol. This allows you to enumerate your commands using BluetoothCommand.allCases.forEach

I've also simplified your code slightly by using an anonymous argument $0 which in this case will correspond to each of your enum cases. I also shortened String.Encoding.utf8 to just .utf8 because I believe its type can be inferred by the compiler.

enum BluetoothCommand: String, CaseIterable {
    case numQueue = "NUM_QUEUE\r"
    case readAll = "READ_ALL\r"
}

func writeValue() {

    if isMyPeripheralConected { //check if myPeripheral is connected to send data
        BluetoothCommand.allCases.forEach {
            let dataToSend: Data = $0.rawValue.data(using: .utf8)!
            myBluetoothPeripheral.writeValue(dataToSend, for: myCharacteristic, type: .withResponse)
        }

    } else {
        print("Not connected")
    }

}