am 6c427617: Merge "support humidity sensor type"
* commit '6c427617be940be32fdebbd9c78f9223b292c814':
support humidity sensor type
diff --git a/api/current.xml b/api/current.xml
index f524509..f76a216 100644
--- a/api/current.xml
+++ b/api/current.xml
@@ -77615,6 +77615,17 @@
visibility="public"
>
</field>
+<field name="TYPE_RELATIVE_HUMIDITY"
+ type="int"
+ transient="false"
+ volatile="false"
+ value="12"
+ static="true"
+ final="true"
+ deprecated="not deprecated"
+ visibility="public"
+>
+</field>
<field name="TYPE_ROTATION_VECTOR"
type="int"
transient="false"
diff --git a/core/java/android/hardware/Sensor.java b/core/java/android/hardware/Sensor.java
index f2b907b..595c7d1 100644
--- a/core/java/android/hardware/Sensor.java
+++ b/core/java/android/hardware/Sensor.java
@@ -97,6 +97,13 @@
*/
public static final int TYPE_ROTATION_VECTOR = 11;
+ /**
+ * A constant describing a relative humidity sensor type.
+ * See {@link android.hardware.SensorEvent SensorEvent}
+ * for more details.
+ */
+ public static final int TYPE_RELATIVE_HUMIDITY = 12;
+
/**
* A constant describing all sensor types.
*/
diff --git a/core/java/android/hardware/SensorEvent.java b/core/java/android/hardware/SensorEvent.java
index 8c55bf3..4a7991fc 100644
--- a/core/java/android/hardware/SensorEvent.java
+++ b/core/java/android/hardware/SensorEvent.java
@@ -304,7 +304,65 @@
* in the clockwise direction (mathematically speaking, it should be
* positive in the counter-clockwise direction).
* </p>
- *
+ *
+ * <h4>{@link android.hardware.Sensor#TYPE_RELATIVE_HUMIDITY
+ * Sensor.TYPE_RELATIVE_HUMIDITY}:</h4>
+ * <ul>
+ * <p>
+ * values[0]: Relative ambient air humidity in percent
+ * </p>
+ * </ul>
+ * <p>
+ * When relative ambient air humidity and ambient temperature are
+ * measured, the dew point and absolute humidity can be calculated.
+ * </p>
+ * <u>Dew Point</u>
+ * <p>
+ * The dew point is the temperature to which a given parcel of air must be
+ * cooled, at constant barometric pressure, for water vapor to condense
+ * into water.
+ * </p>
+ * <center><pre>
+ * ln(RH/100%) + m·t/(T<sub>n</sub>+t)
+ * t<sub>d</sub>(t,RH) = T<sub>n</sub> · ------------------------------
+ * m - [ln(RH/100%) + m·t/(T<sub>n</sub>+t)]
+ * </pre></center>
+ * <dl>
+ * <dt>t<sub>d</sub></dt> <dd>dew point temperature in °C</dd>
+ * <dt>t</dt> <dd>actual temperature in °C</dd>
+ * <dt>RH</dt> <dd>actual relative humidity in %</dd>
+ * <dt>m</dt> <dd>17.62</dd>
+ * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd>
+ * </dl>
+ * <p>for example:</p>
+ * <pre class="prettyprint">
+ * h = Math.log(rh / 100.0) + (17.62 * t) / (243.12 + t);
+ * td = 243.12 * h / (17.62 - h);
+ * </pre>
+ * <u>Absolute Humidity</u>
+ * <p>
+ * The absolute humidity is the mass of water vapor in a particular volume
+ * of dry air. The unit is g/m<sup>3</sup>.
+ * </p>
+ * <center><pre>
+ * RH/100%·A·exp(m·t/(T<sub>n</sub>+t))
+ * d<sub>v</sub>(t,RH) = 216.7 · -------------------------
+ * 273.15 + t
+ * </pre></center>
+ * <dl>
+ * <dt>d<sub>v</sub></dt> <dd>absolute humidity in g/m<sup>3</sup></dd>
+ * <dt>t</dt> <dd>actual temperature in °C</dd>
+ * <dt>RH</dt> <dd>actual relative humidity in %</dd>
+ * <dt>m</dt> <dd>17.62</dd>
+ * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd>
+ * <dt>A</dt> <dd>6.112 hPa</dd>
+ * </dl>
+ * <p>for example:</p>
+ * <pre class="prettyprint">
+ * dv = 216.7 *
+ * (rh / 100.0 * 6.112 * Math.exp(17.62 * t / (243.12 + t)) / (273.15 + t));
+ * </pre>
+ *
* @see SensorEvent
* @see GeomagneticField
*/