ios - 如何将 CBDescriptor 值转换为字符串？

Question

我可以在“didUpdateValeFor描述符:”方法中读取描述符值。以下是我从 BLE 设备获取的描述符日志。

<CBDescriptor: 0x1c445cb60, UUID = Characteristic Format, value = <08ff2427 013110>>
值采用数据格式，其有效范围从 XX 值到 YY 值，我猜它的类型是 uint32 。我无法转换它们。我无法从其他答案中得到任何解决方案。

Answer 1

一般来说，CBDescriptor 有一个 uuid 属性，该属性将是指定的值之一 in the documentation和一个 value 属性。 value 属性的类型取决于 uuid。您可以在每个可能的 CBDescriptor uuid 中找到相关的 value 类型。例如，对于 CBUUIDCharacteristicFormatString，value 是对格式字符串进行编码的 Data 实例。

解码CBDescriptor的示例函数如下所示。您需要添加缺少的 uuid 类型。

func descriptorDescription(for descriptor: CBDescriptor) -> String {

    var description: String?
    var value: String?

    switch descriptor.uuid.uuidString {
    case CBUUIDCharacteristicFormatString:
        if let data = descriptor.value as? Data {
            description = "Characteristic format: "
            value = data.description
        }
    case CBUUIDCharacteristicUserDescriptionString:
        if let val = descriptor.value as? String {
            description = "User description: "
            value = val
        }
    case CBUUIDCharacteristicExtendedPropertiesString:
        if let val = descriptor.value as? NSNumber {
            description = "Extended Properties: "
            value = val.description
        }
    case CBUUIDClientCharacteristicConfigurationString:
        if let val = descriptor.value as? NSNumber {
            description = "Client characteristic configuration: "
            value = val.description
        }
    case CBUUIDServerCharacteristicConfigurationString:
        if let val = descriptor.value as? NSNumber {
            description = "Server characteristic configuration: "
            value = val.description
        }
    case CBUUIDCharacteristicAggregateFormatString:
        if let val = descriptor.value as? String {
            description = "Characteristic aggregate format: "
            value = val
        }
    default:
        break
    }

    if let desc=description, let val = value  {
        return "\(desc)\(val)"
    } else {
        return "Unknown descriptor"
    }
}

对于与CBUUIDCharacteristicFormatString相关的数据的具体解码，您需要引用Bluetooth documentation