Do not repeat similar orientation to observers

Android uses 1° precision in its orientation computation, so it is not
uncommon to be signalled the same orientation several times. There is no
need for observers to be woken up, as the value has not changed.

1 files changed, 11 insertions, 1 deletions

diff --git a/main/src/cgeo/geocaching/DirectionProvider.java b/main/src/cgeo/geocaching/DirectionProvider.java
index 2f54b41..d8ee782 100644
--- a/main/src/cgeo/geocaching/DirectionProvider.java
+++ b/main/src/cgeo/geocaching/DirectionProvider.java
@@ -14,6 +14,12 @@ public class DirectionProvider extends MemorySubject<Float> implements SensorEve
 
     private final SensorManager sensorManager;
 
+    // Previous values signalled to observers to avoid resending the same value when the
+    // device doesn't change orientation. The orientation is usually given with a 1 degree
+    // precision by Android, so it is not uncommon to obtain exactly the same value several
+    // times.
+    private float previous = -1;
+
     public DirectionProvider(final Context context) {
         sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
 
@@ -46,7 +52,11 @@ public class DirectionProvider extends MemorySubject<Float> implements SensorEve
 
     @Override
     public void onSensorChanged(final SensorEvent event) {
-        notifyObservers(event.values[0]);
+        final float direction = event.values[0];
+        if (direction != previous) {
+            notifyObservers(direction);
+            previous = direction;
+        }
     }
 
     /**