iOS：將命令發送到外圍設備並從中接收響應

Question

我正在開發iOS中的核心藍牙應用程序。 我有智能手表設備，正在連接到我開發的應用程序，目的是能夠從其中發現服務和特征，當我嘗試從手表中讀取信息時，會出現以下錯誤

 Bluetooth_iph[2688:614669] Did discover peripheral. peripheral: <CBPeripheral: 0x17daf4d0,   
  identifier = D675EA0B-1342-0C74-9D3D-98CAFA478985, name = BLEDEVICE, state = connecting> 
   rssi: -51, UUID: <CFUUID 0x17d96e80> D675EA0B-1342-0C74-9D3D-98CAFA478985     
  advertisementData: {
kCBAdvDataIsConnectable = 1;
kCBAdvDataLocalName = "BLEDEVICE";
kCBAdvDataServiceUUIDs =     (
    8880
);
kCBAdvDataTxPowerLevel = 7;

  } 
 2014-10-17 10:06:13.695 Bluetooth_iph[2688:614669] WARNING: No service found
 2014-10-17 10:06:18.353 Bluetooth_iph[2688:614669] Peripheral Connected
 2014-10-17 10:06:18.354 Bluetooth_iph[2688:614669]  started  time is 10:06:10 17-10-14
 2014-10-17 10:06:18.354 Bluetooth_iph[2688:614669] Scanning stopped
 2014-10-17 10:06:18.485 Bluetooth_iph[2688:614669] Found a Device Manufacturer Name 
 2014-10-17 10:06:18.541 Bluetooth_iph[2688:614669] Error updating value for characteristic   
 8881 error: Reading is not permitted.

 2014-10-17 10:06:18.601 Bluetooth_iph[2688:614669] Error updating value for characteristic 
 8881 error: Reading is not permitted.

 2014-10-17 10:06:18.662 Bluetooth_iph[2688:614669] Error updating value for characteristic 
 8881 error: Reading is not permitted.

為了發現服務的特性，我編寫如下。

    - (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:
  (CBService   
 *)service error:(NSError *)error

  {
  if (error)
  {
    NSLog(@"Discovered characteristics for %@ with error: %@", service.UUID, [error 
     localizedDescription]);
    return;
  }


   if([service.UUID isEqual:[CBUUID UUIDWithString:@"8880"]])
  {
    for (CBCharacteristic * characteristic in service.characteristics)
    {
        /* Read manufacturer name */
        if([characteristic.UUID isEqual:[CBUUID UUIDWithString:@"8881"]])
        {
            [_discoveredPeripheral readValueForCharacteristic:characteristic];
            NSLog(@"Found a Device Manufacturer Name Characteristic - Read manufacturer 
      name");
        }
    }
  }

   if ( [service.UUID isEqual:[CBUUID UUIDWithString:CBUUIDGenericAccessProfileString]] )
    {
    for (CBCharacteristic *characteristic in service.characteristics)
    {
        /* Read device name */
        if([characteristic.UUID isEqual:[CBUUID UUIDWithString:CBUUIDDeviceNameString]])
        {
            [_discoveredPeripheral readValueForCharacteristic:characteristic];
            NSLog(@"Found a Device Name Characteristic - Read device name");
        }
     }
  }
  }

並為特征更新值

 - (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:  
  (CBCharacteristic *)characteristic error:(NSError *)error
 {
 if (error)
  {
     NSLog(@"Error updating value for characteristic %@ error: %@", characteristic.UUID,   
   [error localizedDescription]);
    return;
  }
}

作為iOS開發的新目標，我的要求是我必須向ble設備發出一些請求，以便它能夠響應，並且應該在iOS應用程序中得到該響應。 以上代碼代表我的知識。 請通過代碼或其他示例幫助我。

Answer 1

您應該檢查CBCharacteristic的properties屬性-它會告訴您可以使用該特性做什么。 從此功能不支持您正在閱讀的消息-要么只能寫它，或者如果它是向中央發送信息，則可能必須使用通知或指示（ CBCharacteristicPropertyNotify和/或在properties設置的CBCharacteristicPropertyIndicate ）。

如果是這種情況，則需要使用[peripheral setNotifyValue:YES forCharacteristic:characteristic]; 當設備具有針對該特性的新數據時，它將調用peripheral:didUpdateNotificationStateForCharacteristic:error:委托方法。