assertion says had race condition; fix it

Use a set instead of a singleton so a late clear doesn't overwrite an
early set.

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

@@ -158,7 +158,7 @@ public class DelegateBase implements DlgClickNotify,
     protected void onPause()
     {
         m_isVisible = false;
-        XWServiceHelper.setListener( null );
+        XWServiceHelper.clearListener( this );
         m_dlgDelegate.onPausing();
     }
 

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

@@ -26,6 +26,9 @@ import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
 import android.os.Bundle;
 
+import java.util.Collections;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.Set;
 
 import org.eehouse.android.xw4.loc.LocUtils;
 
@@ -58,8 +61,8 @@ public class MultiService {
     private static final String ACTION_FETCH_DICT = "_afd";
     private static final String FOR_MISSING_DICT = "_fmd";
 
-    // Shouldn't this be a Set?
+    private Set<MultiEventListener> m_lis = Collections
-    private MultiEventListener m_li;
+        .newSetFromMap(new ConcurrentHashMap<MultiEventListener, Boolean>());
 
     // these do not currently pass between devices so they can change.
     public enum MultiEvent { _INVALID,
@@ -100,28 +103,25 @@ public class MultiService {
 
     public void setListener( MultiEventListener li )
     {
-        synchronized( this ) {
+        m_lis.add( li );
-            // If this is happening, the order of resume/pause isn't what we
-            // expect. Might need to keep a set of these instead of a
-            // singleton.
-            if ( BuildConfig.DEBUG ) {
-                if ( m_li == null && li == null ) {
-                    Assert.fail();
-                } else if ( m_li != null && li != null ) {
-                    Assert.fail();
-                }
-            }
-            m_li = li;
-        }
     }
 
-    public void postEvent( MultiEvent event, Object ... args )
+    public void clearListener( MultiEventListener li )
     {
-        synchronized( this ) {
+        Assert.assertTrue( m_lis.contains( li ) || ! BuildConfig.DEBUG );
-            if ( null != m_li ) {
+        m_lis.remove( li );
-                m_li.eventOccurred( event, args );
+    }
-            }
+
+    public int postEvent( MultiEvent event, Object ... args )
+    {
+        // don't just return size(): concurrency doesn't guarantee isn't
+        // changed
+        int count = 0;
+        for ( MultiEventListener listener : m_lis ) {
+            listener.eventOccurred( event, args );
+            ++count;
         }
+        return count;
     }
 
     public static Intent makeMissingDictIntent( Context context, NetLaunchInfo nli,

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

@@ -39,7 +39,7 @@ import java.util.Map;
 abstract class XWServiceHelper {
     private static final String TAG = XWServiceHelper.class.getSimpleName();  
     private Service mService;
-    private static MultiService s_srcMgr = null;
+    private static MultiService s_srcMgr = new MultiService();
 
     public static enum ReceiveResult { OK, GAME_GONE, UNCONSUMED };
 
@@ -101,19 +101,17 @@ abstract class XWServiceHelper {
 
     public final static void setListener( MultiService.MultiEventListener li )
     {
-        if ( null == s_srcMgr ) {
-            // DbgUtils.logf( "XWService.setListener: registering %s",
-            // li.getClass().getName() );
-            s_srcMgr = new MultiService();
-        }
         s_srcMgr.setListener( li );
     }
 
+    public final static void clearListener( MultiService.MultiEventListener li )
+    {
+        s_srcMgr.clearListener( li );
+    }
+
     protected void postEvent( MultiEvent event, Object ... args )
     {
-        if ( null != s_srcMgr ) {
+        if ( 0 == s_srcMgr.postEvent( event, args ) ) {
-            s_srcMgr.postEvent( event, args );
-        } else {
             Log.d( TAG, "postEvent(): dropping %s event",
                    event.toString() );
         }