flutter_blue_plus 示例无法连接到 esp32

Question

我正在尝试使用 BLE 连接到 esp32 来与我的 flutter 应用程序进行通信。

我在这里克隆了 flutter_blue_plus 示例： https://github.com/boskokg/flutter_blue_plus/tree/master/example

我使用 android studio 模拟器（Pixel 4 XL API 30 Android 11.0）运行示例文件夹。

我的 esp32 代码也来自示例库：

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

BLEServer* pServer = NULL;
BLECharacteristic* pCharacteristic = NULL;
bool deviceConnected = false;
bool oldDeviceConnected = false;
uint32_t value = 0;

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"


class MyServerCallbacks: public BLEServerCallbacks {
    void onConnect(BLEServer* pServer) {
      deviceConnected = true;
      BLEDevice::startAdvertising();
    };

    void onDisconnect(BLEServer* pServer) {
      deviceConnected = false;
    }
};

void setup() {
  Serial.begin(115200);

  // Create the BLE Device
  BLEDevice::init("ESP32 makeNTU");

  // Create the BLE Server
  pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  // Create the BLE Service
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create a BLE Characteristic
  pCharacteristic = pService->createCharacteristic(
                      CHARACTERISTIC_UUID,
                      BLECharacteristic::PROPERTY_READ   |
                      BLECharacteristic::PROPERTY_WRITE  |
                      BLECharacteristic::PROPERTY_NOTIFY |
                      BLECharacteristic::PROPERTY_INDICATE
                    );

  // https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.descriptor.gatt.client_characteristic_configuration.xml
  // Create a BLE Descriptor
  pCharacteristic->addDescriptor(new BLE2902());

  // Start the service
  pService->start();

  // Start advertising
  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
  pAdvertising->addServiceUUID(SERVICE_UUID);
  pAdvertising->setScanResponse(false);
  pAdvertising->setMinPreferred(0x0);  // set value to 0x00 to not advertise this parameter
  BLEDevice::startAdvertising();
  Serial.println("Waiting a client connection to notify...");
}

void loop() {
    // notify changed value
    if (deviceConnected) {
        pCharacteristic->setValue((uint8_t*)&value, 4);
        pCharacteristic->notify();
        value++;
        delay(500); // bluetooth stack will go into congestion, if too many packets are sent, in 6 hours test i was able to go as low as 3ms
    }
    // disconnecting
    if (!deviceConnected && oldDeviceConnected) {
        delay(500); // give the bluetooth stack the chance to get things ready
        pServer->startAdvertising(); // restart advertising
        Serial.println("start advertising");
        oldDeviceConnected = deviceConnected;
    }
    // connecting
    if (deviceConnected && !oldDeviceConnected) {
        // do stuff here on connecting
        oldDeviceConnected = deviceConnected;
    }
}

当我运行我的应用程序时，它看起来像这样：

似乎可以成功扫描某些设备，但不能成功扫描我的esp32。

此外，每次我扫描时，该应用程序每次只能显示 2 个设备。 我根据文档更改了

android/app/src/main/AndroidManifest.xml

： https://pub.dev/packages/flutter_blue_plus

我可以使用 iPhone 中的 nRF Connect 应用程序找到我的 esp32。

那么为什么我的应用程序找不到我的 esp32？我应该改变什么才能让它发挥作用？谢谢！

Answer 1

您应该尝试在物理设备上运行它，而不是模拟器。您扫描的内容可能与模拟器的蓝牙模拟功能有关。