Question

我正在尝试从蓝牙设备（BR-LE4.0-S2）读取数据。我能够连接BLE设备，但无法从中读取数据。我没有关于BLE服务及其特性的任何规范。这就是我的问题- (void)peripheral:didUpdateValueForCharacteristic:error:未被调用。我遵循了教程“https://developer.apple.com/library/ios/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/PerformingCommonCentralRoleTasks/PerformingCommonCentralRoleTasks.html#//apple_ref/doc/uid/TP40013257-CH3-SW2”。以下是我的代码。

我的要求是从BLE设备连续读取数据。非常感谢任何帮助。

- (void)viewDidLoad
{
    self.myCentralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
    self.peripheral = [[CBPeripheral alloc] init];
    self.peripheral.delegate = self;
    [super viewDidLoad];
}

- (void) centralManagerDidUpdateState:(CBCentralManager *)central {

    switch (central.state) {
        case CBCentralManagerStatePoweredOn:
        [self.myCentralManager scanForPeripheralsWithServices:nil options:nil];
            break;
        default:
            NSLog(@"Central Manager did change state");
            break;
    }

}

- (void)centralManager:(CBCentralManager *)central
 didDiscoverPeripheral:(CBPeripheral *)peripheral
     advertisementData:(NSDictionary *)advertisementData
                  RSSI:(NSNumber *)RSSI {

    NSLog(@"Discovered %@", peripheral.name);
    [self.myCentralManager stopScan];
    NSLog(@"Scanning stopped");

    if (self.peripheral != peripheral) {
        self.peripheral = peripheral;
        NSLog(@"Connecting to peripheral %@", peripheral);
        // Connects to the discovered peripheral
    [self.myCentralManager connectPeripheral:peripheral options:nil];
    }
}

- (void)centralManager:(CBCentralManager *)central
didConnectPeripheral:(CBPeripheral *)peripheral {

    NSLog(@"Peripheral connected");

    NSLog(@"Peripheral services : %@",peripheral.services );

    [self.peripheral setDelegate:self];

    [peripheral discoverServices:nil];

}
- (void)peripheral:(CBPeripheral *)peripheral
didDiscoverServices:(NSError *)error {

    if (error) {
        NSLog(@"Error discovering service: %@", [error localizedDescription]);
        return;
    }

    for (CBService *service in peripheral.services) {
        [peripheral discoverCharacteristics:nil forService:nil];
    }
}

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

    int i = 0;
    for (CBCharacteristic *characteristic in service.characteristics) {

[peripheral setNotifyValue:YES forCharacteristic: characteristic];

    }
}

- (void)peripheral:(CBPeripheral *)peripheral
didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic
             error:(NSError *)error {

    NSData *data = characteristic.value;
    NSString *value = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];

    NSLog(@"Value %@",value);
    NSString *stringFromData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    NSLog(@"Data ====== %@", stringFromData);
}


- (void)peripheral:(CBPeripheral *)peripheral
didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic
             error:(NSError *)error {

    if (error) {
        NSLog(@"Error changing notification state: %@",
              [error localizedDescription]);
    }
    NSString *value = [[NSString alloc] initWithData:self.interestingCharacteristic.value encoding:NSUTF8StringEncoding];

    NSLog(@"Value %@",value);

    NSLog(@"description: %@, descriptors: %@, properties: %d, service :%@, value:%@", characteristic.description, characteristic.descriptors, characteristic.properties, characteristic.service, characteristic.value);
    NSData *data = characteristic.value;

    if (characteristic.isNotifying) {
        NSString *stringFromData = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
        [peripheral readValueForCharacteristic:characteristic];

        NSLog(@"Data ====== %@", @"ccdc");

    } else {
        [self.myCentralManager cancelPeripheralConnection:peripheral];

    }

}

- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
{
    NSLog(@"Peripheral Disconnected");
    self.peripheral = nil;

    // We're disconnected, so start scanning again
    NSDictionary *scanOptions = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:NO] forKey:CBCentralManagerScanOptionAllowDuplicatesKey];

    [self.myCentralManager scanForPeripheralsWithServices:nil options:scanOptions];
}

Answer 1

要从BLE外围设备读取值，请执行以下步骤

扫描可用设备

NSDictionary *options = [NSDictionary dictionaryWithObject:[NSNumber numberWithBool:YES] forKey:CBCentralManagerScanOptionAllowDuplicatesKey];
[self.myCentralManager scanForPeripheralsWithServices:nil options:options];`

在检测到设备时，将回拨“didDiscoverPeripheral”委托方法。然后与检测到的BLE设备建立连接

-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {

    //Connect detected device....
    if (!peripheral.isConnected) {
        peripheral.delegate = self;
        [bluetoothManager_ connectPeripheral:peripheral options:nil];

    }
}

成功连接后，请求BLE设备中可用的所有服务

- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral{
NSLog(@"Peripheral Connected");

    // Make sure we get the discovery callbacks
    peripheral.delegate = self;

    // Search only for services that match our UUID
    [peripheral discoverServices:nil];
}

请求每项服务中可用的所有特征

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {

    if (error) {
        NSLog(@"Error discovering services: %@", [error localizedDescription]);
        return;
    }
    // Loop through the newly filled peripheral.services array, just in case there's more than one.
    for (CBService *service in peripheral.services) {
        [peripheral discoverCharacteristics:nil forService:service];
    }
}

一旦我们获得了所需的特征细节，我们需要订阅它，这让外围设备知道我们想要它包含的数据

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

    // Deal with errors (if any)
    if (error) {
        NSLog(@"Error discovering characteristics: %@", [error localizedDescription]);
        return;
    }

    // Again, we loop through the array, just in case.
    for (CBCharacteristic *characteristic in service.characteristics) {
        if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:REQUIRED_CHARA_ID]]) {
            // If it is, subscribe to it
            [peripheral setNotifyValue:YES forCharacteristic:characteristic];
        }
    }
}

完成所有这些步骤后，BLE设备会通过委托方式告知您通知状态的变化

- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error{

    if (error) {
        NSLog(@"Error changing notification state: %@", error.localizedDescription);
    }

    // Notification has started
    if (characteristic.isNotifying) {
        NSLog(@"Notification began on %@", characteristic);
    }
}

您将通过以下方法接收来自BLE设备的任何通知

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    if (error) {
        NSLog(@"Error reading characteristics: %@", [error localizedDescription]);
        return;
    }

    if (characteristic.value != nil) {
          //value here.        
    }
}

Answer 2

Swift 版itZme's answer由于<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:cal="http://www.parasoft.com/wsdl/calculator/"> <soapenv:Header/> <soapenv:Body> <cal:subtractResponse> <cal:Result>${result}</cal:Result> </cal:subtractResponse> </soapenv:Body> </soapenv:Envelope>未被调用而导致少许修改（您还需要保留强大的参考资料）外围设备为了连接，如下）：

扫描可用设备：

didConnectToPeripheral

在检测到设备时，会收到一个回复＆＃34; didDiscoverPeripheral＆＃34;委托方法。然后与检测到的BLE设备建立连接。 但首先要保留外围设备的强大参考：

centralManager.scanForPeripheralsWithServices(nil, options: nil)

剩下的应该是这样的：

private var peripherals: [CBPeripheral] = []

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

  if peripheral.state != .connected {
    self.peripherals.append(peripheral)
    peripheral.delegate = self
    centralManager.connectPeripheral(peripheral , options: nil)
  }
}

Answer 3

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

    for newChar: CBCharacteristic in service.characteristics!{

        peripheral.readValue(for: newChar)

        if newChar.properties.rawValue == 0x10 || newChar.properties.rawValue == 0x8C{

            peripheral.setNotifyValue(true, for: newChar)
        }
        else if newChar.properties.rawValue == 0x12{

            peripheral.setNotifyValue(true, for: newChar)
        }
     }


 func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {

    print(characteristic)
 }

Answer 4

首先你必须执行read（）函数。如果执行read（）函数，那么“didUpdateValueForCharesteristics”将会运行。你可以在这个函数中读取字符串值。这很简单。

从BLE设备读取数据

4 个答案: