Merge 4b999030

Change-Id: Ibb94ba77ec8588f5e7636cf6a038b143e3dcb2bd

api/current.xml

@@ -93618,6 +93618,17 @@
  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"

core/java/android/hardware/Sensor.java

@@ -97,6 +97,13 @@ public class Sensor {
      */
     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.
      */

core/java/android/hardware/SensorEvent.java

@@ -304,7 +304,65 @@ public class SensorEvent {
      * 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&#183;t/(T<sub>n</sub>+t)
+     * t<sub>d</sub>(t,RH) = T<sub>n</sub> &#183; ------------------------------
+     *                 m - [ln(RH/100%) + m&#183;t/(T<sub>n</sub>+t)]
+     * </pre></center>
+     * <dl>
+     * <dt>t<sub>d</sub></dt> <dd>dew point temperature in &deg;C</dd>
+     * <dt>t</dt>             <dd>actual temperature in &deg;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 &deg;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%&#183;A&#183;exp(m&#183;t/(T<sub>n</sub>+t))
+     * d<sub>v</sub>(t,RH) = 216.7 &#183; -------------------------
+     *                           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 &deg;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 &deg;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
      */