WIP: critical bug EXT-4837 ([NUX] When filter results in null state, provide a message suggesting the user try global search.)

Partial implementation of help text in case of empty list when filtered for Nearby and Recent lists of People panel:
 * Extracted support implementation of several messages for empty list depend of filtering from LLGroupList to LLFlatListEx
 * change inheritence of LLGroupList and LLAvatarList from LLFlatListView to LLFlatListViewEx
 * updated panel people to init Nearby & Recent lists with appropriate messages.

--HG--
branch : product-engine

2 files changed, 88 insertions, 4 deletions

diff --git a/indra/llui/llflatlistview.cpp b/indra/llui/llflatlistview.cpp
index 82f054c4b7..990bf5cd22 100644
--- a/indra/llui/llflatlistview.cpp
+++ b/indra/llui/llflatlistview.cpp
@@ -1,10 +1,10 @@
 /** 
  * @file llflatlistview.cpp
- * @brief LLFlatListView base class
+ * @brief LLFlatListView base class and extension to support messages for several cases of an empty list.
  *
  * $LicenseInfo:firstyear=2009&license=viewergpl$
  * 
- * Copyright (c) 2009, Linden Research, Inc.
+ * Copyright (c) 2009-2010, Linden Research, Inc.
  * 
  * Second Life Viewer Source Code
  * The source code in this file ("Source Code") is provided by Linden Lab
@@ -1122,4 +1122,38 @@ void LLFlatListView::detachItems(std::vector<LLPanel*>& detached_items)
 	}
 }
 
+
+/************************************************************************/
+/*             LLFlatListViewEx implementation                          */
+/************************************************************************/
+LLFlatListViewEx::Params::Params()
+: no_items_msg("no_items_msg")
+, no_filtered_items_msg("no_filtered_items_msg")
+{
+
+}
+
+LLFlatListViewEx::LLFlatListViewEx(const Params& p)
+:	LLFlatListView(p)
+, mNoFilteredItemsMsg(p.no_filtered_items_msg)
+, mNoItemsMsg(p.no_items_msg)
+{
+
+}
+
+void LLFlatListViewEx::updateNoItemsMessage(bool items_filtered)
+{
+	if (items_filtered)
+	{
+		// items were filtered
+		setNoItemsCommentText(mNoFilteredItemsMsg);
+	}
+	else
+	{
+		// list does not contain any items at all
+		setNoItemsCommentText(mNoItemsMsg);
+	}
+
+}
+
 //EOF
diff --git a/indra/llui/llflatlistview.h b/indra/llui/llflatlistview.h
index e3c07e811f..f7d094f7e7 100644
--- a/indra/llui/llflatlistview.h
+++ b/indra/llui/llflatlistview.h
@@ -1,10 +1,10 @@
 /** 
  * @file llflatlistview.h
- * @brief LLFlatListView base class
+ * @brief LLFlatListView base class and extension to support messages for several cases of an empty list.
  *
  * $LicenseInfo:firstyear=2009&license=viewergpl$
  * 
- * Copyright (c) 2009, Linden Research, Inc.
+ * Copyright (c) 2009-2010, Linden Research, Inc.
  * 
  * Second Life Viewer Source Code
  * The source code in this file ("Source Code") is provided by Linden Lab
@@ -430,4 +430,54 @@ private:
 	commit_signal_t	mOnReturnSignal;
 };
 
+/**
+ * Extends LLFlatListView functionality to show different messages when there are no items in the
+ * list depend on whether they are filtered or not.
+ *
+ * Class provides one message per case of empty list.
+ * It also provides protected updateNoItemsMessage() method to be called each time when derived list
+ * is changed to update base mNoItemsCommentTextbox value.
+ *
+ * It is implemented to avoid duplication of this functionality in concrete implementations of the
+ * lists. It is intended to be used as a base class for lists which should support two different
+ * messages for empty state. Can be improved to support more than two messages via state-to-message map.
+ */
+class LLFlatListViewEx : public LLFlatListView
+{
+public:
+	struct Params : public LLInitParam::Block<Params, LLFlatListView::Params>
+	{
+		/**
+		 * Contains a message for empty list when it does not contain any items at all.
+		 */
+		Optional<std::string>	no_items_msg;
+
+		/**
+		 * Contains a message for empty list when its items are removed by filtering.
+		 */
+		Optional<std::string>	no_filtered_items_msg;
+		Params();
+	};
+
+	// *WORKAROUND: two methods to overload appropriate Params due to localization issue:
+	// no_items_msg & no_filtered_items_msg attributes are not defined as translatable in VLT. See EXT-5931
+	void setNoItemsMsg(const std::string& msg) { mNoItemsMsg = msg; }
+	void setNoFilteredItemsMsg(const std::string& msg) { mNoFilteredItemsMsg = msg; }
+
+protected:
+	LLFlatListViewEx(const Params& p);
+
+	/**
+	 * Applies a message for empty list depend on passed argument.
+	 *
+	 * @param items_filtered - if true message for filtered items will be set, otherwise for
+	 * completely empty list.
+	 */
+	void updateNoItemsMessage(bool items_filtered);
+
+private:
+	std::string mNoFilteredItemsMsg;
+	std::string mNoItemsMsg;
+};
+
 #endif