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Question

我正在尝试使用mbed API向我的自定义BLE GATT服务添加一些特征用户描述。到目前为止，我的工作基于this代码结构。但是，我想为这些特征添加名称。关于如何做到这一点，我找不到很多信息。但是，下面是将信息添加到特征的代码。

GattCharacteristic（）的构造函数将GattAttribtues数组作为可选参数。您可以将用户描述填充到GattAttribute中并将其传递给特征。我有这个结构为一个特征工作，但我正在努力复制它为3个字符。我无法将整个事情复制3次，因为我将其运行到很多关于已经定义的数组等的问题上。如果我在阵列中堆叠描述，那么GattArray就不会接受它？

uint16_t newServiceUUID         = 0xA000;
uint16_t PercentageUUID         = 0xA001;
uint16_t TimeUUID               = 0xA002;
uint16_t UseProfileUUID         = 0xA003;

const static char     DEVICE_NAME[]        = "Device"; // Device name
static const uint16_t uuid16_list[]        = {0xFFF};  
static uint8_t percentageValue[10] = {0};
GattAttribute nameDescr( BLE_UUID_DESCRIPTOR_CHAR_USER_DESC, (uint8_t *)"Percentage", strlen("Percentage"));
GattAttribute *descriptors[] = {&nameDescr};

WriteOnlyArrayGattCharacteristic<uint8_t,sizeof(percentageValue)> 
        percentageChar( PercentageUUID, 
                        percentageValue,
                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_EXTENDED_PROPERTIES,
                        descriptors, 
                        sizeof(descriptors) / sizeof(GattAttribute*) );

GattCharacteristic *characteristics[] = {&percentageChar, &timeChar, &UseProfileChar};
GattService        newService(newServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));

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使用下面的讨论，我现在有：

#include <string>
class MyGattArray
{

public:
    MyGattArray( const std::string& name ) : 
        attr( BLE_UUID_DESCRIPTOR_CHAR_USER_DESC, (uint8_t *)name.c_str(), (name.size()+1) )
    {
        descriptors[0] = &attr;
    }

    GattAttribute attr;
    GattAttribute *descriptors[1];
};

和

static uint8_t percentageValue[10] = {0};
MyGattArray PercentageName( "Percentage" );
GattAttribute *descriptors[] = {&(PercentageName.attr)};

WriteOnlyArrayGattCharacteristic<uint8_t,sizeof(percentageValue)> 
        percentageChar( PercentageUUID, 
                        percentageValue,
                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_EXTENDED_PROPERTIES,
                        descriptors, 
                        sizeof(descriptors) / sizeof(GattAttribute*) );

这会构建，但不会给特征命名。

Answer 1

这是模板助手类的命题，可以封装特征对象及其描述符。如果您不熟悉模板，则有点难以理解。

template <typename T, unsigned NUM_ELEMENTS, template <typename T, unsigned NUM_ELEMENTS> class CharacType>
class CharacteristicWithNameDescrptorHelper
{
public:
    CharacteristicWithNameDescrptorHelper( const          UUID &uuid,
                                           T              valuePtr[NUM_ELEMENTS],
                                           uint8_t        additionalProperties,
                                           const std::string& characName ) : 
        name( characName )
    {
        descriptor = new GattAttribute( BLE_UUID_DESCRIPTOR_CHAR_USER_DESC, (uint8_t *)name.c_str(), name.size() ) 
        // create descriptor array
        descriptors[0] = descriptor;
        // create characteristic object:
        charac = new CharacType<T,NUM_ELEMENTS>( uuid, valuePtr, additionalProperties, descriptors, 1 );
    }

    ~CharacteristicWithNameDescrptorHelper()
    {
        delete charac;
        delete descriptor;
    }

    CharacType<T,NUM_ELEMENTS>* charac;
    std::string name;
    GattAttribute* descriptor;
    GattAttribute *descriptors[1];
};

然后，你只需：

CharacteristicWithNameDescrptorHelper<uint8_t,sizeof(percentageValue),WriteOnlyArrayGattCharacteristic> 
        percentageChar( PercentageUUID, 
                        percentageValue,
                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_EXTENDED_PROPERTIES,
                        "Percentage" );

GattCharacteristic *characteristics[] = {percentageChar.charac};
GattService        newService(newServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));

将特征用户描述添加到多个自定义C ++ BLE GATT服务

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1 个答案: