Swift BLE "didDiscoverServices" not executing. Am I missing something? - ios

Question

I've been reading the tutorial to use the nRF8001 from Adafruit and connecting it to an iOS device via Arduino. So far I've set up everything correctly and it works fine in their app.
I'm trying to write my own app that (for now) does the exact same thing, I read their tutorial and from what I understand I copied the code as close as I could, so far I can get the connection and most things seem to be working (UI-wise), however I can't seem to do anything past connecting to the device:
Here's my code for AFTER connecting:
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("Peripheral found: " + (peripheral.name ?? "Unknown Name"))
peripheralsFoundNames.append((peripheral.name ?? "Unknown Name"))
peripheralsFoundData.append((advertisementData.description ))
peripheralsFoundCB.append(peripheral)
peripheralsFoundRSSIs.append(RSSI)
}
func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
print("Connected to device!")
displayStatusAlert(localmsg: "Connection Succesful!")
NotificationCenter.default.post(name: Notification.Name(rawValue: DEVICE_READY_KEY), object: self)
data?.length = 0 //clear any data that might be stored
peripheral.discoverServices([BLETemperatureService])
print("Here at didConnect, connected to:" + peripheral.name!)
// Here needs to add code to check if it's a single or multi-channel device via the advertisement data or some other constant, maybe the name?
}
As you can see, I am calling explicitly peripheral.discoverServices, and then i have a print statement that executes. Then I have the following (NOTE NONE OF THE BELOW LINES SEEM TO EXECUTE AT ANY TIME (AT LEAST NOT THE PRINT STATEMENTS):
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
print("here at diddisoverservices")
if ((error) != nil){
displayStatusAlert(localmsg: "Error: \n" + (error?.localizedDescription ?? "Error Unknown" ))
}
guard let services = peripheral.services
else{
return
}
for service in services {
peripheral.discoverCharacteristics(nil, for: service)
}
print ("Discovered!")
}
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
if ((error) != nil){
displayStatusAlert(localmsg: "Error: \n" + (error?.localizedDescription ?? "Error Unknown" ))
}
guard let characteristics = service.characteristics
else{
return
}
for characteristic in characteristics {
//looks for the right characteristic
print("looking for characteristic")
if characteristic.uuid.isEqual(BLERXCharacteristic) {
deviceConnectedRXChar = characteristic
//Once found, subscribe to the this particular characteristic
peripheral.setNotifyValue(true, for: deviceConnectedRXChar!)
peripheral.readValue(for: characteristic)
print("Rx Characteristic: \(characteristic.uuid)")
}
if characteristic.uuid.isEqual(BLETXCharacteristic){
deviceConnectedTXChar = characteristic
print("Tx Characteristic: \(characteristic.uuid)")
}
peripheral.discoverDescriptors(for: characteristic)
}
print ("Characteristic discovered")
}
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
if characteristic == deviceConnectedRXChar {
if let ASCIIstring = NSString(data: characteristic.value!, encoding: String.Encoding.utf8.rawValue) {
receivedDataString = ASCIIstring
print("Value Recieved: \((receivedDataString as String))")
NotificationCenter.default.post(name: Notification.Name(rawValue: DEVICE_SENT_DATA), object: nil)
}
}

Answer 1

func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) is a CBPeripheralDelegate method.
So what you were missing is setting the CBPeripheral object delegate.
So just before doing peripheral.discoverServices([BLETemperatureService]), you need to do peripheral.delegate = self.