無法從外設發現藍牙服務

Question

構建一個應用程序以連接到Arduino藍牙模塊，發現設備正常，但是當涉及到發現服務時，它始終爲零。 我沒事到發現服務功能，我真的不明白

這裏是我的代碼：

import UIKit 
import CoreBluetooth 

class Devices: UITableViewController, CBCentralManagerDelegate, CBPeripheralDelegate { 

    var devices = [String]() 
    var centralManager : CBCentralManager! 
    var peripheral: CBPeripheral! 
    var central: CBCentralManager! 
    var peripheralArray: [CBPeripheral] = [] 
    var service : CBService! 

    var deviceConnected = false 

    override func viewDidLoad() { 
     super.viewDidLoad() 
     self.refreshControl = UIRefreshControl() 
     self.refreshControl!.addTarget(self, action: "scanForDevices:", forControlEvents: UIControlEvents.ValueChanged) 
     tableView.tableFooterView = UIView() 
     central = CBCentralManager(delegate: self, queue: nil) 

    } 

    override func didReceiveMemoryWarning() { 
     super.didReceiveMemoryWarning() 
    } 


    func centralManagerDidUpdateState(central: CBCentralManager) { 
     if central.state == CBCentralManagerState.PoweredOn { 
      print("Bluetooth On") 
     } 
     else { 
      print("Bluetooth off or not supported") 
     } 
    } 


    func scanForDevices(sender: AnyObject) { 

     devices.removeAll() 
     print("Scanning") 
     central.scanForPeripheralsWithServices(nil, options: nil) 

     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (Int64)(2 * NSEC_PER_SEC)), dispatch_get_main_queue()) { 
      self.central.stopScan() 
      self.refreshControl?.endRefreshing() 
      print("Stopped Scanning") 
     } 


    } 

    func centralManager(central: CBCentralManager, didDiscoverPeripheral peripheral: CBPeripheral, advertisementData: [String : AnyObject], RSSI: NSNumber) { 


     (advertisementData as NSDictionary).objectForKey(CBAdvertisementDataLocalNameKey) as? NSString 

     let list = String(peripheral.name!) 

     if (devices.contains(list)){ 
     } else {devices.append(list) 
      peripheralArray.append(peripheral) 

     } 

     tableView.reloadData() 


    } 

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
     return devices.count 
    } 

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell { 

     let cell = tableView.dequeueReusableCellWithIdentifier("device")! as UITableViewCell 

     cell.textLabel?.text = devices[indexPath.row] 

     return cell 

    } 

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) { 

     tableView.deselectRowAtIndexPath(indexPath, animated: true) 

     if(deviceConnected == false){ 
      self.central.connectPeripheral(peripheralArray[indexPath.row], options: nil) 

      deviceConnected = true 
     }else{ 
      self.central.cancelPeripheralConnection(peripheralArray[indexPath.row]) 
      deviceConnected = false 
     } 

     discoverServices() 

     self.peripheral = peripheralArray[indexPath.row] 
     print(self.peripheral.services) 



    } 


    func discoverServices(){ 



     for service in peripheral.services! { 
      let thisService = service as? CBService 
       if let thisService = thisService{ 
        peripheral.discoverCharacteristics(nil, forService: thisService) 
      } 
     } 
    } 




    } 

Answer 1

你直接去發現特徵不首先發現服務。在致電discoverCharacteristics之前，您需要致電discoverServices。一旦發現服務，將調用peripheral:didDiscoverServices:委託方法，您可以使用它來觸發特徵發現。

對於discoverServices呼叫，您可以通過它，你要發現的CBUUID地址數組（推薦），或者，如果你不知道你想要的服務，您可以通過它nil發現所有服務IT具有。