Fix the bug where you cannot use up arrow to enter the suggestions box

Review at http://gwt-code-reviews.appspot.com/239801

Review by: jlabanca@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7814 8db76d5a-ed1c-0410-87a9-c151d255dfc7

user/src/com/google/gwt/user/client/ui/SuggestBox.java

diff --git a/user/src/com/google/gwt/user/client/ui/SuggestBox.java b/user/src/com/google/gwt/user/client/ui/SuggestBox.java
index 4ac452e..a82dbe2 100644
--- a/user/src/com/google/gwt/user/client/ui/SuggestBox.java
+++ b/user/src/com/google/gwt/user/client/ui/SuggestBox.java
@@ -366,6 +366,8 @@
       // Make sure that the menu is actually showing. These keystrokes
       // are only relevant when choosing a suggestion.
       if (isSuggestionListShowing()) {
+        // If nothing is selected, getSelectedItemIndex will return -1 and we
+        // will select index 0 (the first item) by default.
         suggestionMenu.selectItem(suggestionMenu.getSelectedItemIndex() + 1);
       }
     }
@@ -375,7 +377,17 @@
       // Make sure that the menu is actually showing. These keystrokes
       // are only relevant when choosing a suggestion.
       if (isSuggestionListShowing()) {
-        suggestionMenu.selectItem(suggestionMenu.getSelectedItemIndex() - 1);
+        // if nothing is selected, then we should select the last suggestion by
+        // default. This is because, in some cases, the suggestions menu will
+        // appear above the text box rather than below it (for example, if the
+        // text box is at the bottom of the window and the suggestions will not
+        // fit below the text box). In this case, users would expect to be able
+        // to use the up arrow to navigate to the suggestions.
+        if (suggestionMenu.getSelectedItemIndex() == -1) {
+          suggestionMenu.selectItem(suggestionMenu.getNumItems() - 1);
+        } else {
+          suggestionMenu.selectItem(suggestionMenu.getSelectedItemIndex() - 1);
+        }
       }
     }
 

user/test/com/google/gwt/user/client/ui/SuggestBoxTest.java

diff --git a/user/test/com/google/gwt/user/client/ui/SuggestBoxTest.java b/user/test/com/google/gwt/user/client/ui/SuggestBoxTest.java
index 1bd7fb6..87b8a9e 100644
--- a/user/test/com/google/gwt/user/client/ui/SuggestBoxTest.java
+++ b/user/test/com/google/gwt/user/client/ui/SuggestBoxTest.java
@@ -170,6 +170,41 @@
     assertEquals("A", display.getSuggestion(0).getReplacementString());
     assertEquals("B", display.getSuggestion(1).getReplacementString());
   }
+  
+  public void testSuggestionSelection() {
+    MultiWordSuggestOracle oracle = new MultiWordSuggestOracle();
+    oracle.setDefaultSuggestionsFromText(Arrays.asList("A", "B"));
+    TestSuggestionDisplay display = new TestSuggestionDisplay();
+    SuggestBox box = new SuggestBox(oracle, new TextBox(), display);
+    box.setAutoSelectEnabled(false);
+    RootPanel.get().add(box);
+    box.showSuggestionList();
+
+    // If nothing is selected, moving down will select the first item
+    assertNull(display.getCurrentSelection());
+    display.moveSelectionDown();
+    assertEquals("A", display.getCurrentSelection().getReplacementString());
+    
+    // Once something is selected, selections are made as expected, but we do
+    // not move outside the box
+    display.moveSelectionDown();
+    assertEquals("B", display.getCurrentSelection().getReplacementString());
+    display.moveSelectionDown();
+    assertEquals("B", display.getCurrentSelection().getReplacementString());
+    display.moveSelectionUp();
+    assertEquals("A", display.getCurrentSelection().getReplacementString());
+    display.moveSelectionUp();
+    assertEquals("A", display.getCurrentSelection().getReplacementString());
+    
+    // Reset the suggestions so that nothing is selected again
+    display.hideSuggestions();
+    box.showSuggestionList();
+    assertNull(display.getCurrentSelection());
+    
+    // If nothing is selected, moving up will select the last item
+    display.moveSelectionUp();
+    assertEquals("B", display.getCurrentSelection().getReplacementString());
+  }
 
   public void testShowFirst() {
     SuggestBox box = createSuggestBox();