altoslib: Add units change notification list

[fw/altos] / altoslib / AltosPreferences.java

diff --git a/altoslib/AltosPreferences.java b/altoslib/AltosPreferences.java
index 47196d6e70b89342ef3f876207bef574bcb941f4..e50b9b5cf05a9a856b1b60fb3af6fe604ac3db39 100644 (file)
--- a/altoslib/AltosPreferences.java
+++ b/altoslib/AltosPreferences.java
@@ -367,6 +367,8 @@ public class AltosPreferences {
                set_common_frequencies(new_frequencies);
        }
 
+       static LinkedList<AltosUnitsListener> units_listeners;
+
        public static boolean imperial_units() {
                synchronized(backend) {
                        return AltosConvert.imperial_units;
@@ -379,5 +381,24 @@ public class AltosPreferences {
                        backend.putBoolean(unitsPreference, imperial_units);
                        flush_preferences();
                }
+               if (units_listeners != null) {
+                       for (AltosUnitsListener l : units_listeners) {
+                               l.units_changed(imperial_units);
+                       }
+               }
+       }
+
+       public static void register_units_listener(AltosUnitsListener l) {
+               synchronized(backend) {
+                       if (units_listeners == null)
+                               units_listeners = new LinkedList<AltosUnitsListener>();
+                       units_listeners.add(l);
+               }
+       }
+
+       public static void unregister_units_listener(AltosUnitsListener l) {
+               synchronized(backend) {
+                       units_listeners.remove(l);
+               }
        }
 }