update studylist display when words added

Add listener interface to DBUtils and hook StudyListDelegate into it so
that if a word is added while the list is being displayed the new word
shows up immediately.

xwords4/android/app/src/main/java/org/eehouse/android/xw4/DBUtils.java

@@ -88,6 +88,12 @@ public class DBUtils {
     private static HashSet<DBChangeListener> s_listeners =
         new HashSet<DBChangeListener>();
 
+    public static interface StudyListListener {
+        void onWordAdded( String word, int langCode );
+    }
+    private static Set<StudyListListener> s_slListeners
+        = new HashSet<StudyListListener>();
+
     private static SQLiteOpenHelper s_dbHelper = null;
 
     public static class Obit {
@@ -1896,6 +1902,20 @@ public class DBUtils {
         }
     }
 
+    protected static void addStudyListChangedListener( StudyListListener lnr )
+    {
+        synchronized( s_slListeners ) {
+            s_slListeners.add( lnr );
+        }
+    }
+
+    protected static void removeStudyListChangedListener( StudyListListener lnr )
+    {
+        synchronized( s_slListeners ) {
+            s_slListeners.remove( lnr );
+        }
+    }
+
     public static void loadDB( Context context )
     {
         copyGameDB( context, false );
@@ -2157,6 +2177,7 @@ public class DBUtils {
             db.insert( DBHelper.TABLE_NAME_STUDYLIST, null, values );
             db.close();
         }
+        notifyStudyListListeners( word, lang );
     }
 
     public static int[] studyListLangs( Context context )
@@ -2605,6 +2626,15 @@ public class DBUtils {
         return result;
     }
 
+    private static void notifyStudyListListeners( String word, int lang )
+    {
+        synchronized( s_slListeners ) {
+            for ( StudyListListener listener : s_slListeners ) {
+                listener.onWordAdded( word, lang );
+            }
+        }
+    }
+
     private static void notifyListeners( long rowid, GameChangeType change )
     {
         synchronized( s_listeners ) {

xwords4/android/app/src/main/java/org/eehouse/android/xw4/StudyListDelegate.java

@@ -48,7 +48,8 @@ import java.util.Set;
 
 public class StudyListDelegate extends ListDelegateBase
     implements OnItemSelectedListener, SelectableItem,
-               View.OnLongClickListener, View.OnClickListener {
+               View.OnLongClickListener, View.OnClickListener,
+               DBUtils.StudyListListener {
 
     protected static final int NO_LANG = -1;
 
@@ -87,6 +88,20 @@ public class StudyListDelegate extends ListDelegateBase
         initOrFinish( getIntent() );
     }
 
+    @Override
+    protected void onResume()
+    {
+        super.onResume();
+        DBUtils.addStudyListChangedListener( this );
+    }
+
+    @Override
+    protected void onPause()
+    {
+        DBUtils.removeStudyListChangedListener( this );
+        super.onPause();
+    }
+
     @Override
     protected boolean handleBackPressed()
     {
@@ -166,6 +181,17 @@ public class StudyListDelegate extends ListDelegateBase
         }
     }
 
+    //////////////////////////////////////////////////
+    // DBUtils.StudyListListener
+    //////////////////////////////////////////////////
+    @Override
+    public void onWordAdded( String word, int langCode )
+    {
+        if ( langCode == m_langCodes[m_langPosition] ) {
+            loadList();
+        }
+    }
+
     //////////////////////////////////////////////////
     // DlgDelegate.DlgClickNotify interface
     //////////////////////////////////////////////////