better handling on key down/up event.

Author: happyhua

gwt-material/src/main/java/gwt/material/design/client/ui/MaterialSearch.java

@@ -212,25 +212,21 @@ public void onKeyUp(KeyUpEvent event) {
 
                 // Selection logic using key down event to navigate the search results
                 int totalItems = searchResultPanel.getWidgetCount();
-                if (event.getNativeEvent().getKeyCode() == KeyCodes.KEY_DOWN) {
-                    if (curSel >= totalItems) {
-                        setCurSel(getCurSel());
-                        applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel - 1));
-                    } else {
-                        setCurSel(getCurSel() + 1);
-                        applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel));
+                if (totalItems > 0) {
+                    if (event.getNativeEvent().getKeyCode() == KeyCodes.KEY_DOWN) {
+                    	if (++curSel >= totalItems)
+                    		curSel = 0;
+                    	
+                    	applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel));
                     }
-                }
 
-                // Selection logic using key up event to navigate the search results
-                if (event.getNativeEvent().getKeyCode() == KeyCodes.KEY_UP) {
-                    if (curSel <= -1) {
-                        setCurSel(-1);
-                        applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel));
-                    } else {
-                        setCurSel(getCurSel() - 1);
-                        applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel));
-                    }
+                    // Selection logic using key up event to navigate the search results
+                    if (event.getNativeEvent().getKeyCode() == KeyCodes.KEY_UP) {
+                    	if (--curSel < 0)
+                    		curSel = totalItems - 1;
+                    	
+                    	applyHighlightedItem((MaterialLink) searchResultPanel.getWidget(curSel));
+                    }                	
                 }
             }