可以通过设置“client_config”属性来解决。在gatt服务端注册特性时,需要将其添加到gatt_db库中,并在特性声明中设置“client_config”属性为“1”。这将启用通知,使客户端能够获取到所有信息。
示例代码:
#include "esp_gatts_api.h"
#include "esp_gap_ble_api.h"
***省略其他代码***
// 添加特性到GATT库中
esp_err_t add_char_to_db(esp_gatt_if_t gatts_if, esp_bt_uuid_t *svc_uuid, esp_bt_uuid_t *char_uuid, esp_gatt_perm_t perm, uint16_t *handle, uint16_t min_len, uint16_t max_len, uint8_t *init_val, bool need_auth) {
esp_err_t res = ESP_OK;
esp_gatt_id_t svc_id;
esp_gatt_id_t char_id;
esp_gatt_char_prop_t property = 0;
esp_attr_value_t value;
uint8_t char_prop = ESP_GATT_CHAR_PROP_BIT_READ | ESP_GATT_CHAR_PROP_BIT_NOTIFY;
// 创建服务ID
memcpy(&svc_id.uuid, svc_uuid, sizeof(esp_bt_uuid_t));
svc_id.inst_id = 0;
// 注册服务到GATT库
res = esp_ble_gatts_create_service(gatts_if, &svc_id, GATTS_NUM_HANDLE_TEST_SERVICE);
if (res != ESP_OK) {
return res;
}
// 创建特性ID
memcpy(&char_id.uuid, char_uuid, sizeof(esp_bt_uuid_t));
char_id.inst_id = 0;
// 设置特性属性
property |= ESP_GATT_CHAR_PROP_BIT_WRITE_NR;
property |= ESP_GATT_CHAR_PROP_BIT_READ;
property |= ESP_GATT_CHAR_PROP_BIT_NOTIFY;
// 设置特性值
value.attr_len = strlen((char *)init_val);
value.attr_max_len = max_len;
value.attr_value = init_val;
// 在GATT库中注册该特性
res = esp_ble_gatts_add_char(gatts_if, &svc_id, &char_id, max_len,
property, &value, &perm);
if (res != ESP_OK) {
return res;
}
// 设置特性声明
esp_gatt_char_prop_t char_prop = ESP_GATT_CHAR_PROP_BIT_READ | ESP_GATT_CHAR_PROP_BIT_NOTIFY;
esp_gatt_char_inst_t char_inst;
char_inst.char_handle = handle[IDX_CHAR_VAL];
char_inst.uuid = *char_uuid;
esp_ble_gatts_add_char_descr(gatts_if, &svc_id, &char_inst.uuid,
NULL, NULL, ESP_GATT_PERM_NONE, NULL);
// 设置客户端配置
uint16_t client_config = 0;
esp_ble_gatts_add_char_descr(gatts_if, &svc_id, &char_inst.uuid,
NULL, NULL, ESP_GATT_PERM_READ | ESP_GATT_PERM_WRITE, &client_config);
return ESP_OK;
}