proximity trigger

app/src/main/java/com/jens/automation2/ActivityManageTriggerProximity.java

@@ -86,11 +86,23 @@ public class ActivityManageTriggerProximity extends Activity
             }
         });
 
-        startPreview();
-
         rsProximity.setValues(20f, 80f);
     }
 
+    @Override
+    protected void onResume()
+    {
+        super.onResume();
+        startPreview();
+    }
+
+    @Override
+    protected void onPause()
+    {
+        super.onPause();
+        stopPreview();
+    }
+
     void startPreview()
     {
         sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
@@ -113,6 +125,12 @@ public class ActivityManageTriggerProximity extends Activity
         }
     }
 
+    void stopPreview()
+    {
+        if(proximitySensor != null)
+            sensorManager.unregisterListener(proximitySensorEventListener);
+    }
+
     SensorEventListener proximitySensorEventListener = new SensorEventListener()
     {
         @Override