Added SensorManager.getMinDelay()

Exposed the new "min delay" sensor property through native and
java sensor apis. This allows the caller to know what is the
maximum rate at which a sensor can return events, or, if a sensor
works in "update" mode (events returned only when the value changes).

Also augmented SensorManager.regusterSensorEvent() so that it can
accept a value in microsecond in addition to the 4 constants already
defined.

Change-Id: If425e9979892666df8c989d7de3c362230fa19e0

3 files changed, 21 insertions, 5 deletions

diff --git a/core/java/android/hardware/Sensor.java b/core/java/android/hardware/Sensor.java
index 3490ac0..b49a409 100644
--- a/core/java/android/hardware/Sensor.java
+++ b/core/java/android/hardware/Sensor.java
@@ -92,6 +92,7 @@ public class Sensor {
     private float   mMaxRange;
     private float   mResolution;
     private float   mPower;
+    private int     mMinDelay;
     private int     mLegacyType;
 
 
@@ -147,6 +148,15 @@ public class Sensor {
         return mPower;
     }
 
+    /**
+     * @return the minimum delay allowed between two events in microsecond
+     * or zero if this sensor only returns a value when the data it's measuring
+     * changes.
+     */
+    public int getMinDelay() {
+        return mMinDelay;
+    }
+
     int getHandle() {
         return mHandle;
     }
diff --git a/core/java/android/hardware/SensorManager.java b/core/java/android/hardware/SensorManager.java
index e6750e6..5cc8d5d 100644
--- a/core/java/android/hardware/SensorManager.java
+++ b/core/java/android/hardware/SensorManager.java
@@ -935,7 +935,8 @@ public class SensorManager
      *        received faster or slower than the specified rate. Usually events
      *        are received faster. The value must be one of
      *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
-     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
+     *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}
+     *        or, the desired delay between events in microsecond.
      *
      * @return <code>true</code> if the sensor is supported and successfully
      *         enabled.
@@ -967,6 +968,7 @@ public class SensorManager
      *        are received faster. The value must be one of
      *        {@link #SENSOR_DELAY_NORMAL}, {@link #SENSOR_DELAY_UI},
      *        {@link #SENSOR_DELAY_GAME}, or {@link #SENSOR_DELAY_FASTEST}.
+     *        or, the desired delay between events in microsecond.
      *
      * @param handler
      *        The {@link android.os.Handler Handler} the
@@ -992,16 +994,17 @@ public class SensorManager
                 delay = 0;
                 break;
             case SENSOR_DELAY_GAME:
-                delay = 20;
+                delay = 20000;
                 break;
             case SENSOR_DELAY_UI:
-                delay = 60;
+                delay = 60000;
                 break;
             case SENSOR_DELAY_NORMAL:
-                delay = 200;
+                delay = 200000;
                 break;
             default:
-                return false;
+                delay = rate;
+                break;
         }
 
         synchronized (sListeners) {
diff --git a/core/jni/android_hardware_SensorManager.cpp b/core/jni/android_hardware_SensorManager.cpp
index 7b23418..e29495c 100644
--- a/core/jni/android_hardware_SensorManager.cpp
+++ b/core/jni/android_hardware_SensorManager.cpp
@@ -38,6 +38,7 @@ struct SensorOffsets
     jfieldID    range;
     jfieldID    resolution;
     jfieldID    power;
+    jfieldID    minDelay;
 } gSensorOffsets;
 
 /*
@@ -74,6 +75,7 @@ sensors_module_get_next_sensor(JNIEnv *env, jobject clazz, jobject sensor, jint
     env->SetFloatField(sensor, sensorOffsets.range,      list->getMaxValue());
     env->SetFloatField(sensor, sensorOffsets.resolution, list->getResolution());
     env->SetFloatField(sensor, sensorOffsets.power,      list->getPowerUsage());
+    env->SetIntField(sensor, sensorOffsets.minDelay,     list->getMinDelay());
     
     next++;
     return next<count ? next : 0;
@@ -154,6 +156,7 @@ nativeClassInit (JNIEnv *_env, jclass _this)
     sensorOffsets.range       = _env->GetFieldID(sensorClass, "mMaxRange",  "F");
     sensorOffsets.resolution  = _env->GetFieldID(sensorClass, "mResolution","F");
     sensorOffsets.power       = _env->GetFieldID(sensorClass, "mPower",     "F");
+    sensorOffsets.minDelay    = _env->GetFieldID(sensorClass, "mMinDelay",  "I");
 }
 
 static JNINativeMethod gMethods[] = {