diff --git a/xwords4/android/XWords4/res/values/strings.xml b/xwords4/android/XWords4/res/values/strings.xml
index 7e4530eb2..cdf097df1 100644
--- a/xwords4/android/XWords4/res/values/strings.xml
+++ b/xwords4/android/XWords4/res/values/strings.xml
@@ -132,6 +132,8 @@
 	<string name="str_not_your_turn">You can\'t do that; it\'s not your turn!</string>
 	<string name="str_no_peek_robot_tiles">No peeking at the robot\'s tiles!</string>
 	<string name="str_cant_trade_mid_move">Remove played tiles before exchanging.</string>
+    <string name="str_no_empty_trade">Trade cancelled because no tiles
+      selected.  (It\'s still your turn.)</string>
 	<string name="str_too_few_tiles_left_to_trade">Too few tiles left to exchange.</string>
 	<string name="str_cant_undo_tileassign">Tile assignment can\'t be undone.</string>
 	<string name="str_cant_hint_while_disabled">The hint feature is disabled for this game.  Enable it for a new game using the Settings dialog.</string>
diff --git a/xwords4/android/XWords4/src/org/eehouse/android/xw4/BoardActivity.java b/xwords4/android/XWords4/src/org/eehouse/android/xw4/BoardActivity.java
index 6a5d164dc..6cc141453 100644
--- a/xwords4/android/XWords4/src/org/eehouse/android/xw4/BoardActivity.java
+++ b/xwords4/android/XWords4/src/org/eehouse/android/xw4/BoardActivity.java
@@ -970,6 +970,9 @@ public class BoardActivity extends XWActivity
             case UtilCtxt.ERR_CANT_TRADE_MID_MOVE:
                 resid = R.string.str_cant_trade_mid_move;
                 break;
+            case UtilCtxt.ERR_NO_EMPTY_TRADE:
+                resid = R.string.str_no_empty_trade;
+                break;
             case UtilCtxt.ERR_TOO_FEW_TILES_LEFT_TO_TRADE:
                 resid = R.string.str_too_few_tiles_left_to_trade;
                 break;
diff --git a/xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/UtilCtxt.java b/xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/UtilCtxt.java
index 1df94c2dc..d4f9dcd77 100644
--- a/xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/UtilCtxt.java
+++ b/xwords4/android/XWords4/src/org/eehouse/android/xw4/jni/UtilCtxt.java
@@ -97,9 +97,10 @@ public interface UtilCtxt {
     static final int ERR_REG_SERVER_SANS_REMOTE = 11;
     static final int STR_NEED_BT_HOST_ADDR = 12;
     static final int ERR_CANT_TRADE_MID_MOVE = 13;
-    static final int ERR_CANT_UNDO_TILEASSIGN = 14;
-    static final int ERR_CANT_HINT_WHILE_DISABLED = 15;
-    static final int ERR_RELAY_BASE = 16;
+    static final int ERR_NO_EMPTY_TRADE = 14;
+    static final int ERR_CANT_UNDO_TILEASSIGN = 15;
+    static final int ERR_CANT_HINT_WHILE_DISABLED = 16;
+    static final int ERR_RELAY_BASE = 17;
     void userError( int id );
 
     void notifyGameOver();