手表靠近嘴时如何启动应用程序

Question

我想开发一个 android 佩戴应用程序，当手表靠近嘴巴时可以听取用户的声音。我怎样才能检测到这种运动？

Answer 1

我设计了一个具有类似功能的 covid-19 wear 应用程序来防止用户触摸他们的 mouth/eyes（面部区域）。您可以注册重力传感器侦听器并检测用户何时将手举向 mouth/head 区域。

private SensorManager mSensorManager;

//register in #onResume

 mSensorManager.registerListener(this,  mSensorManager.getDefaultSensor(Sensor.TYPE_GRAVITY), SensorManager.SENSOR_DELAY_NORMAL);

用户佩戴手表时，重力感应器测得的重力x-component在手朝下时为+9.8，在手朝上朝嘴时为-9.8。当手表戴在右手上时，这些值是相反的。由于向上或向下的值可能不精确，您可以留出一些空间，因此您可以使用 GRAVITY THRESHOLD of (7.0f) 而不是 9.8。如果花费的时间小于 2000000000 纳秒的阈值，您也可以认为 up/down 移动成功：

// An movement to the mouth and down that takes more than 2 seconds will not be registered (in nanoseconds).
    private static final long TIME_THRESHOLD_NS = TimeUnit.SECONDS.toNanos(2);

    private static final float HAND_DOWN_GRAVITY_X_THRESHOLD = -.040f;
    private static final float HAND_UP_GRAVITY_X_THRESHOLD = -.010f;

 @Override
    public void onSensorChanged(SensorEvent event) {
        detectMouthTouched(event.values[0], event.timestamp);
    }

private void detectMouthTouched(float xGravity, long timestamp) {

        if ((xGravity <= HAND_DOWN_GRAVITY_X_THRESHOLD)
                || (xGravity >= HAND_UP_GRAVITY_X_THRESHOLD)) {

            if (timestamp - mLastTime < TIME_THRESHOLD_NS) {
                // Hand is down when yValue is negative.
                onFaceTouched(xGravity <= HAND_DOWN_GRAVITY_X_THRESHOLD);
            }

            mLastTime = timestamp;
        }
    }

    
    private void onFaceTouched(boolean handDown) {
        if (mHandDown != handDown) {
            mHandDown = handDown;

        }
    }

手表靠近嘴时如何启动应用程序

How to launch the application when the watch is near mouth

android

android-wear-2.0