从 peripheral:didUpdateNotificationStateForCharacteristic 收到错误

Question

我开发了一个蓝牙低功耗外设应用程序，它成功地与第二个 BLE 中央应用程序连接。但是，我无法让中央应用程序订阅外围设备提供的服务特征之一的通知。在中央应用程序中，我有以下内容：

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
{
    if ([service.UUID isEqual:[CBUUID UUIDWithString:IMMEDIATE_ALERT_SERVICE_UUID]])  {
        for (CBCharacteristic *aChar in service.characteristics) {
            if ([aChar.UUID isEqual:[CBUUID UUIDWithString:ALERT_LEVEL_CHARACTERISTIC_UUID]]) {
                [peripheral setNotifyValue:YES forCharacteristic:aChar];

不幸的是，这失败了，并且在委托方法 peripheral:didUpdateNotificationStateForCharacteristic 处收到错误（错误类型为 "unknown"）。如果我在上面的代码中打印特征对象（aChar），我得到如下：

<CBCharacteristic: 0x1464f560, UUID = 2A06, properties = 0x2, value = (null), notifying = NO>

注意通知=否。如何设置外设使特性通知？

Answer 1

好的，我明白了。在外围端，需要设置特性的属性来启用通知。您可以使用 CBCharacteristicPropertyNotify 属性执行此操作。例如，以下是您可以如何创建特征：

CBMutableCharacteristic *alertLevelCharacteristic = 
[[CBMutableCharacteristic alloc] initWithType:alertLevelCharacteristicUUID
                                   properties:CBCharacteristicPropertyRead | CBCharacteristicPropertyNotify
                                        value: nil permissions:CBAttributePermissionsReadable];

从 peripheral:didUpdateNotificationStateForCharacteristic 收到错误

Error received from peripheral:didUpdateNotificationStateForCharacteristic

bluetooth-lowenergy

cbperipheral

cbcentralmanager

cbperipheralmanager