Android Things UserSensor.Builder - 无法创建距离传感器驱动程序

Question

我正在尝试为标准HC-SR04超声波传感器创建Android Things驱动程序。我相信我已经得到正确的事件序列：see footer，但一直无法将其注册为UserSensor。

userSensor = UserSensor.Builder() 
    .setName("HC-SR04 Ultrasonic Distance Sensor") 
    .setVersion(1) 
    // If boolean "on face or not," should I use something linear like TYPE_LIGHT 
    .setType(Sensor.TYPE_PROXIMITY) 
    .setDriver(this) // UserSensorDriver 
    .build() 

在这一点上，注册UserSensor与UserDriverManager（完成），并注册它与SensorManager之间有什么区别？有没有什么能够阻止它在传感器列表中出现？我是否需要等到传感器像“sensorManager.registerDynamicSensorCallback”那样“准备就绪”？

val sensorManager = context.getSystemService(Context.SENSOR_SERVICE) as SensorManager 
sensorManager.registerListener(this, // SensorEventListener.onSensorChanged 
    sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY), 
    SensorManager.SENSOR_DELAY_NORMAL) 

无论我怎么努力，我得到“E /的SensorManager：传感器或listener为null”（因为空值不应该在尽可能多的潜行这甚至在科特林更令人惊讶）

---

我的传感器/ also a gist：

/** Callback for when the distance changes "enough to care" */ 
interface SignificantDistanceChangeListener { 
    fun onDistanceChanged(distanceCm: Float) 
} 

/** 
* User Sensor - Ultrasonic range finder 
*/ 
class HCSR04(context: Context, val sdcl: SignificantDistanceChangeListener) : UserSensorDriver(), SensorEventListener, AutoCloseable { 
    private val LOG = Logger.getLogger(this.javaClass.name) 
    private val gpio = PeripheralManagerService().openGpio("BCM23") 
    private val distanceReading: BlockingQueue<Float> = ArrayBlockingQueue(1) 
    // Choreography of each ping 
    private val scheduler: ScheduledExecutorService = Executors.newScheduledThreadPool(1) 
    private val userSensor: UserSensor 

    init { 
     userSensor = UserSensor.Builder() 
       .setName("HC-SR04 Ultrasonic Distance Sensor") 
       .setVersion(1) 
       .setType(Sensor.TYPE_PROXIMITY) // Could this be something more linear like TYPE_LIGHT 
       .setDriver(this) 
       .build() 
     UserDriverManager.getManager().registerSensor(userSensor) 

     val sensorManager = context.getSystemService(Context.SENSOR_SERVICE) as SensorManager 
     LOG.info("ALL Sensors: ${sensorManager.getSensorList(Sensor.TYPE_ALL)}") 

     sensorManager.registerDynamicSensorCallback(object : SensorManager.DynamicSensorCallback() { 
      override fun onDynamicSensorConnected(sensor: Sensor) { 
       LOG.info("onDynamicSensorConnected") 
       if (sensor.type == Sensor.TYPE_PROXIMITY) { 
        sensorManager.registerListener(
          this@HCSR04, 
          sensor, 
          SensorManager.SENSOR_DELAY_NORMAL 
        ) 
       } 
      } 
     }) 

    } 

    val gpioEdgeCallback = object : GpioCallback() { 
     // Track the reply rise/fall 
     private val startMs = AtomicLong() 
     private val startValid = AtomicBoolean(false) 

     private fun calculate() { 
      val elapsed = (System.nanoTime()/1000) - startMs.get() 
      if (startValid.get() && elapsed > 0) { 
       distanceReading.put(elapsed * 34000/2f) 
      } else { 
       LOG.warning("Discarding edge callback ${startMs.get()} ${startValid.get()} $elapsed") 
      } 
      startValid.set(false) 
     } 

     override fun onGpioEdge(gpio: Gpio?): Boolean { 
      if (gpio != null) { 
       if (gpio.value) { 
        startMs.set(System.nanoTime()/1000) 
        startValid.set(true) 
       } else { 
        calculate() 
       } 
       LOG.finer("GPIO input edge: ${System.nanoTime()/1000} ${gpio.value}") 
      } 
      return true 
     } 

     override fun onGpioError(gpio: Gpio?, error: Int) = LOG.severe("$gpio Error event $error") 
    } 

    /** Launch a new thread to get the distance, then block until we have a result */ 
    override fun read(): UserSensorReading { 
     distanceReading.clear() 

     gpio.setDirection(Gpio.DIRECTION_OUT_INITIALLY_LOW) 
     gpio.setActiveType(Gpio.ACTIVE_HIGH) 
     gpio.value = false 

     scheduler.schedule({ gpio.value = true }, 1, TimeUnit.MICROSECONDS) 
     scheduler.schedule({ gpio.value = false }, 11, TimeUnit.MICROSECONDS) 
     scheduler.schedule({ 
      gpio.setDirection(Gpio.DIRECTION_IN) 
      gpio.setActiveType(Gpio.ACTIVE_HIGH) // redundant? 
      gpio.setEdgeTriggerType(Gpio.EDGE_BOTH) 
      gpio.registerGpioCallback(gpioEdgeCallback) 
     }, 12, TimeUnit.MICROSECONDS) 

     val distanceCm = distanceReading.take() 
     gpio.unregisterGpioCallback(gpioEdgeCallback) 
     LOG.info("New distance reading: $distanceCm") 
     return UserSensorReading(floatArrayOf(distanceCm)) 
    } 

    /** from @SensorEventListener */ 
    override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) = LOG.info("$sensor accuracy change: $accuracy") 

    /** 
    * from @SensorEventListener 
    */ 
    override fun onSensorChanged(event: SensorEvent) = sdcl.onDistanceChanged(event.values[0]) 

    /** from @AutoCloseable */ 
    override fun close() { 
     LOG.warning("Closing Sensor HCSR04") 
     UserDriverManager.getManager().unregisterSensor(userSensor) 
     gpio.close() 
     scheduler.shutdownNow() 
    } 
} 

Answer 1

有一件事你可以考虑正在改变传感器类型。 TYPE_PROXIMITY是电流变换传感器，在当前预览版中受支持。但它也是一个唤醒传感器，可能还没有完全支持。你可以尝试修改您的传感器定义中使用自定义的类型，而不是：

userSensor = UserSensor.Builder() 
     .setName("HC-SR04 Ultrasonic Distance Sensor") 
     .setVersion(1) 
     .setCustomType(Sensor.TYPE_DEVICE_PRIVATE_BASE, 
       "com.example.ultrasonic", 
       Sensor.REPORTING_MODE_CONTINUOUS) 
     .setDriver(this) 
     .build() 

在这一点上，就是与UserDriverManager（完成）注册UserSensor，并与注册的SensorManager它有什么区别？

您无法直接注册UserSensor与SensorManager。 Android SensorManager API的存在使客户端应用程序能够读取内置于设备中的传感器的数据。 UserDriverManager API的存在使Android Things开发人员能够使用相同的SensorManager API将新传感器添加到系统中，您可能想要在代码的其他位置读取它们。

换句话说，你建立一个UserSensor来通过UserDriverManager将你的自定义传感器数据注入框架。您使用SensorManager来提取提供给框架的数据并将其用于客户端应用程序。

是否有任何东西阻止它在传感器列表中显示？

你应该能够测试此使用SensorManager.getDynamicSensorList()（不一样的getSensorList()方法）的传感器触发回调之后。

我是否需要等到sensorManager.registerDynamicSensorCallback的传感器“准备就绪”？

动态回调会告诉您新驱动程序何时成功注册到框架。在调用onDynamicSensorConnected()之前，您将无法附加侦听器或查询传感器本身。