Android - 获取接近传感器的最小值和最大值

Question

The app i am building makes use of the proximity sensor. Trying it in different phones i found that the proximity sensor has different (min,max) values in different phones (my htc sensation has 0 for covered and 9 for uncovered while xperia has 0 for covered and 1 for uncovered).So the question is: How do i get the proximity sensor's min max values ??

Answer 1

I think minimum value for proximity Sensor is 0 for all devices. and to get maximum range...

    SensorManager sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    Sensor proximitySensor = sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
    proximitySensor.getMaximumRange();

Answer 2

According documentation :

Some proximity sensors only support a binary near or far measurement.
In this case, the sensor should report its maximum range value in the far state
and a lesser value in the near state

So proximity sensor could even had no min and max values. Then you should just compare its value with proximitySensor.getMaximumRange() .

Answer 3

Each proximity sensor is different. You have to monitor the values in onSensorChanged() and remember min and max value. It's working fine. Here is my code for checking near state.

    private float proximityCalibratedMax = Float.MIN_VALUE;

    ...

    public void onSensorChanged(SensorEvent event) {

            if(event.values[0] > proximityCalibratedMax){
                proximityCalibratedMax = event.values[0];
            }

            if (event.sensor.getType() == Sensor.TYPE_PROXIMITY && proximityCalibratedMax != Float.MIN_VALUE) {
                if (event.values[0] < proximityCalibratedMax) {
                    prevNear = true;
                    sensorTimestamp = new Date().getTime();

                } else {
                    long currentTimestamp = new Date().getTime();
                    prevNear = false;
                    openAutifyCarMode();

                }
            }
        }