Swift 3，展开外设名称（蓝牙BLE）

Question

I'm developing an iOS app using Swift 3 / X-Code. This app requires bluetooth communication and I've read a few tutorials and stuff on getting it to work. So far (UI-wise) everything is working. However I'm having issues with the following, since most of the tutorials I've read are not updated to Swift 3 I believe that might be the issue here:

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
    //What to do when it discovers a peripheral, add it to the array list
    //print("Adding peripherals found to array: " + peripheral.name!)
    //peripheralsFound.append(peripheral.name!)
    print("Peripheral found!")

}

The above code has a few lines commented out, I want the peripherals found to be added to an array, however if I un-comment any line with peripheral.name! on it the app crashes with the error "unexpectedly found nil while unwrapping optional value"

I believe it has to do with the peripheral.name! Which was fixed by X-code itself (it added the ! or else it won't compile) I can't make peripheral.name an optional apparently or the app won't compile and I don't know if there's any other way to get the name of the peripherals found, I'd appreciate any guidance. Thank you!

Answer 1

You can add a default value to the print statement using ?? "..."

    print("Adding peripherals found to array: " + (peripheral.name ?? "name was nil"))

This will keep you from having to force it or you can just do a simple check with an if let

  if let unwrappedName = peripheral.name {
    print("Adding peripherals found to array: " + unwrappedName)
  }

I suggest you read about optionals and how they work so you don't have to rely on the IDE to do all the corrections for you.

Answer 2

Use optional binding to safely unwrap the optional value.

var peripheralNames = [String]()

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
    if let name = peripheral.name {
        peripheralNames.append(name)
        print("Adding peripheral found to array: " + name)
    }
    print("Peripheral found!")
}

Answer 3

Swift 3: Try This

var arrayPeripheral: [CBPeripheral] = []
var arrayPeripheralStringName:[String] = []

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber){

    let peripheralLocalName_advertisement = ((advertisementData as NSDictionary).value(forKey: "kCBAdvDataLocalName")) as? String

    if (((advertisementData as NSDictionary).value(forKey: "kCBAdvDataLocalName")) != nil){

        if !(self.arrayPeripheral.contains(peripheral)){

            self.arrayPeripheral.append(peripheral)

            self.arrayPeripheralStringName.append(peripehral.name)               

            peripheral.delegate = self
        }
    }
}