Make timer to check relay for messages non-repeating, and don't

[re]set it when there are no networked games on the device. I didn't
add a change to explicitly set it when creating the first networked
game, but that doesn't seem to be necessary.

xwords4/android/XWords4/src/org/eehouse/android/xw4/DBUtils.java

@@ -751,6 +751,15 @@ public class DBUtils {
         return result;
     }
 
+    public static boolean haveRelayGames( Context context )
+    {
+        long[][] rowIDss = new long[1][];
+        String[] relayIDs = getRelayIDs( context, rowIDss );
+        boolean result = null != relayIDs && 0 < relayIDs.length;
+        DbgUtils.logf( "haveRelayGames() => %b", result );
+        return result;
+    }
+
     public static void addDeceased( Context context, String relayID, 
                                     int seed )
     {

xwords4/android/XWords4/src/org/eehouse/android/xw4/OnBootReceiver.java

@@ -43,7 +43,7 @@ public class OnBootReceiver extends BroadcastReceiver {
     protected static void startTimers( Context context )
     {
         NagTurnReceiver.restartTimer( context );
-        RelayReceiver.restartTimer( context );
+        RelayReceiver.setTimer( context );
     }
 
 }

xwords4/android/XWords4/src/org/eehouse/android/xw4/PollListPreference.java

@@ -51,7 +51,7 @@ public class PollListPreference extends ListPreference
     {
         String valstr = (String)newValue;
         int val = Integer.parseInt(valstr);
-        RelayReceiver.restartTimer( m_context, val * 1000 );
+        RelayReceiver.setTimer( m_context, val * 1000 );
 
         setSummaryToMatch( valstr );
         return true;

xwords4/android/XWords4/src/org/eehouse/android/xw4/RelayReceiver.java

@@ -36,25 +36,26 @@ public class RelayReceiver extends BroadcastReceiver {
         RelayService.timerFired( context );
     }
 
-    public static void restartTimer( Context context )
+    public static void setTimer( Context context )
     {
-        restartTimer( context, 1000 * XWPrefs.getProxyInterval( context ) );
+        setTimer( context, 1000 * XWPrefs.getProxyInterval( context ) );
     }
 
-    public static void restartTimer( Context context, long interval_millis )
+    public static void setTimer( Context context, long interval_millis )
     {
+        DbgUtils.logf( "RelayReceiver.restartTimer(%d)", interval_millis );
         AlarmManager am =
             (AlarmManager)context.getSystemService( Context.ALARM_SERVICE );
 
         Intent intent = new Intent( context, RelayReceiver.class );
         PendingIntent pi = PendingIntent.getBroadcast( context, 0, intent, 0 );
 
-        if ( interval_millis > 0 ) {
+        // Check if we have any relay games
-            long first_millis = SystemClock.elapsedRealtime() + interval_millis;
+        if ( interval_millis > 0 && DBUtils.haveRelayGames( context ) ) {
-            am.setInexactRepeating( AlarmManager.ELAPSED_REALTIME_WAKEUP, 
+            long fire_millis = SystemClock.elapsedRealtime() + interval_millis;
-                                    first_millis, // first firing
+            am.set( AlarmManager.ELAPSED_REALTIME_WAKEUP, fire_millis, pi );
-                                    interval_millis, pi );
         } else {
+            DbgUtils.logf( "RelayReceiver.restartTimer(): cancelling" );
             // will happen if user's set getProxyInterval to return 0
             am.cancel( pi );
         }

xwords4/android/XWords4/src/org/eehouse/android/xw4/RelayService.java

@@ -348,6 +348,7 @@ public class RelayService extends XWService
                     } else if ( registerWithRelayIfNot() ) {
                         requestMessages();
                     }
+                    RelayReceiver.setTimer( this );
                     break;
                 default:
                     Assert.fail();
@@ -371,7 +372,7 @@ public class RelayService extends XWService
     {
         if ( shouldMaintainConnection() ) {
             long interval_millis = getMaxIntervalSeconds() * 1000;
-            RelayReceiver.restartTimer( this, interval_millis );
+            RelayReceiver.setTimer( this, interval_millis );
         }
         stopThreads();
         super.onDestroy();