Android CGM阅读器BLE问题：无法接收GATT广播及后台数据获取失败

一、广播接收不稳定修复 #

问题根源 #

动态广播注册生命周期不匹配、IntentFilter Action与Service发送的不严格一致，或是Android 8.0+静态广播限制导致接收失效。

代码修正 #

1. MainActivity中动态注册广播

private BroadcastReceiver gattUpdateReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {
            // 处理服务发现逻辑
            handleGattServices(BluetoothLeService.getSupportedGattServices());
        } else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {
            // 解析血糖数据
            byte[] rawData = intent.getByteArrayExtra(BluetoothLeService.EXTRA_DATA);
            parseGlucoseData(rawData);
        }
        // 补充其他Action处理（连接成功/断开等）
    }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    // 注册广播过滤器
    IntentFilter filter = new IntentFilter();
    filter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);
    filter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
    filter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
    filter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
    registerReceiver(gattUpdateReceiver, filter);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    unregisterReceiver(gattUpdateReceiver);
}

2. BluetoothLeService中规范广播发送

private static final String ACTION_GATT_SERVICES_DISCOVERED = "com.your.package.ACTION_GATT_SERVICES_DISCOVERED";
private static final String ACTION_DATA_AVAILABLE = "com.your.package.ACTION_DATA_AVAILABLE";
public static final String EXTRA_DATA = "com.your.package.EXTRA_DATA";

private void broadcastUpdate(String action) {
    sendBroadcast(new Intent(action));
}

private void broadcastUpdate(String action, byte[] data) {
    Intent intent = new Intent(action);
    intent.putExtra(EXTRA_DATA, data);
    sendBroadcast(intent);
}

// 服务发现回调中触发广播
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
    if (status == BluetoothGatt.GATT_SUCCESS) {
        mGattServices = gatt.getServices();
        broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
    }
}

二、后台数据获取处理 #

问题根源 #

Android后台限制（Doze模式、App Standby）导致服务被回收，定时任务失效。

代码修正 #

1. 将BluetoothLeService改为前台服务

@Override
public void onCreate() {
    super.onCreate();
    // 创建通知渠道（Android 8.0+必填）
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel channel = new NotificationChannel(
                "CGM_CHANNEL",
                "血糖监测服务",
                NotificationManager.IMPORTANCE_LOW
        );
        NotificationManager manager = getSystemService(NotificationManager.class);
        manager.createNotificationChannel(channel);
    }
    // 启动前台服务
    Notification notification = new NotificationCompat.Builder(this, "CGM_CHANNEL")
            .setContentTitle("CGM监测中")
            .setContentText("持续获取血糖数据")
            .setSmallIcon(R.drawable.ic_cgm)
            .build();
    startForeground(1001, notification);
}

2. 用WorkManager实现稳定定时任务

注：Android 12+ PeriodicWorkRequest最小间隔为15分钟，若需60秒间隔，需结合前台服务+Handler实现

// MainActivity中初始化定时任务
PeriodicWorkRequest cgmSyncRequest = new PeriodicWorkRequest.Builder(
        CgmSyncWorker.class, 15, TimeUnit.MINUTES)
        .setConstraints(new Constraints.Builder()
                .setRequiredNetworkType(NetworkType.NOT_REQUIRED)
                .build())
        .build();
WorkManager.getInstance(this).enqueue(cgmSyncRequest);

// 自定义Worker类
public class CgmSyncWorker extends Worker {
    public CgmSyncWorker(@NonNull Context context, @NonNull WorkerParameters params) {
        super(context, params);
    }

    @NonNull
    @Override
    public Result doWork() {
        // 执行BLE连接与数据获取逻辑
        Intent serviceIntent = new Intent(getApplicationContext(), BluetoothLeService.class);
        getApplicationContext().startForegroundService(serviceIntent);
        return Result.success();
    }
}

三、catchNewGlucValue方法修正 #

问题根源 #

服务未绑定完成就执行数据获取，或是特征值读取/通知逻辑缺失。

代码修正 #

private BluetoothLeService mBluetoothLeService;
private ServiceConnection mServiceConnection = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        BluetoothLeService.LocalBinder binder = (BluetoothLeService.LocalBinder) service;
        mBluetoothLeService = binder.getService();
        // 服务绑定成功后立即触发数据获取
        catchNewGlucValue();
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        mBluetoothLeService = null;
    }
};

private void catchNewGlucValue() {
    if (mBluetoothLeService == null) {
        // 重新绑定服务
        Intent intent = new Intent(this, BluetoothLeService.class);
        bindService(intent, mServiceConnection, BIND_AUTO_CREATE);
        return;
    }
    // 获取血糖特征值（替换为你的CGM设备UUID）
    BluetoothGattCharacteristic glucoseChar = getGlucoseCharacteristic();
    if (glucoseChar != null) {
        // 开启特征值通知（推荐），替代主动读取
        mBluetoothLeService.setCharacteristicNotification(glucoseChar, true);
        // 若需主动读取
        // mBluetoothLeService.readCharacteristic(glucoseChar);
    }
}

private BluetoothGattCharacteristic getGlucoseCharacteristic() {
    List<BluetoothGattService> services = mBluetoothLeService.getSupportedGattServices();
    if (services == null) return null;
    // 血糖服务UUID：00001808-0000-1000-8000-00805f9b34fb
    // 血糖特征值UUID：00002a18-0000-1000-8000-00805f9b34fb
    for (BluetoothGattService service : services) {
        if (service.getUuid().equals(UUID.fromString("00001808-0000-1000-8000-00805f9b34fb"))) {
            return service.getCharacteristic(UUID.fromString("00002a18-0000-1000-8000-00805f9b34fb"));
        }
    }
    return null;
}

四、额外注意事项 #

• 权限申请：Android 12+需动态申请BLUETOOTH_SCAN、BLUETOOTH_CONNECT、ACCESS_FINE_LOCATION权限
• BLE连接优化：优先保持长连接+特征值通知，避免频繁断开重连，提升稳定性与续航
• 错误处理：在GATT回调中处理连接失败、服务发现失败场景，添加自动重连逻辑

内容的提问来源于stack exchange，提问作者Marco Chiesi