From 71f6194f01fef4c5653d5b1e910236c0e41af71d Mon Sep 17 00:00:00 2001
From: Jeremy Ruston <jeremy@osmosoft.com>
Date: Thu, 17 Jan 2013 13:52:46 +0000
Subject: [PATCH] Introduce a simple listview that scrolls to newly inserted
 entries

---
 core/modules/widgets/list/list.js             | 50 ++++++++++++++++++-
 .../widgets/list/listviews/scroller.js        | 31 ++++++++++++
 core/templates/PageTemplate.tid               |  2 +-
 3 files changed, 81 insertions(+), 2 deletions(-)
 create mode 100644 core/modules/widgets/list/listviews/scroller.js

diff --git a/core/modules/widgets/list/list.js b/core/modules/widgets/list/list.js
index 06679126c..afd39fd7e 100644
--- a/core/modules/widgets/list/list.js
+++ b/core/modules/widgets/list/list.js
@@ -15,6 +15,11 @@ The list widget
 var ListWidget = function(renderer) {
 	// Save state
 	this.renderer = renderer;
+	// Initialise the listviews if they've not been done already
+	if(!this.listViews) {
+		ListWidget.prototype.listViews = {};
+		$tw.modules.applyMethods("listview",this.listViews);
+	}
 	// Generate widget elements
 	this.generate();
 };
@@ -182,9 +187,24 @@ ListWidget.prototype.findListElementByTitle = function(startIndex,title) {
 	return undefined;
 };
 
+ListWidget.prototype.postRenderInDom = function() {
+	this.listview = this.chooseListView();
+	this.history = [];
+};
+
+/*
+Select the appropriate list viewer
+*/
+ListWidget.prototype.chooseListView = function() {
+	// Instantiate the list view
+	var listviewName = this.renderer.getAttribute("listview");
+	var ListView = this.listViews[listviewName];
+	return ListView ? new ListView(this) : null;
+};
+
 ListWidget.prototype.refreshInDom = function(changedAttributes,changedTiddlers) {
 	// Reexecute the widget if any of our attributes have changed
-	if(changedAttributes.itemClass || changedAttributes.template || changedAttributes.editTemplate || changedAttributes.emptyMessage || changedAttributes.type || changedAttributes.filter || changedAttributes.template) {
+	if(changedAttributes.itemClass || changedAttributes.template || changedAttributes.editTemplate || changedAttributes.emptyMessage || changedAttributes.type || changedAttributes.filter || changedAttributes.template || changedAttributes.history || changedAttributes.listview) {
 		// Regenerate and rerender the widget and replace the existing DOM node
 		this.generate();
 		var oldDomNode = this.renderer.domNode,
@@ -193,6 +213,11 @@ ListWidget.prototype.refreshInDom = function(changedAttributes,changedTiddlers)
 	} else {
 		// Handle any changes to the list, and refresh any nodes we're reusing
 		this.handleListChanges(changedTiddlers);
+		// Update the history list
+		var history = this.renderer.getAttribute("history");
+		if(history && changedTiddlers[history]) {
+			this.handleHistoryChanges();
+		}
 	}
 };
 
@@ -255,6 +280,29 @@ ListWidget.prototype.handleListChanges = function(changedTiddlers) {
 	}
 };
 
+/*
+Handle any changes to the history list
+*/
+ListWidget.prototype.handleHistoryChanges = function() {
+	// Get the history data
+	var historyAtt = this.renderer.getAttribute("history"),
+		newHistory = this.renderer.renderTree.wiki.getTiddlerData(historyAtt,[]);
+	// Ignore any entries of the history that match the previous history
+	var entry = 0;
+	while(entry < newHistory.length && entry < this.history.length && newHistory[entry].title === this.history[entry].title) {
+		entry++;
+	}
+	// Navigate forwards to each of the new tiddlers
+	while(entry < newHistory.length) {
+		if(this.listview && this.listview.navigateTo) {
+			this.listview.navigateTo(newHistory[entry]);
+		}
+		entry++;
+	}
+	// Update the history
+	this.history = newHistory;
+};
+
 exports.list = ListWidget;
 
 })();
diff --git a/core/modules/widgets/list/listviews/scroller.js b/core/modules/widgets/list/listviews/scroller.js
new file mode 100644
index 000000000..30a4ef68d
--- /dev/null
+++ b/core/modules/widgets/list/listviews/scroller.js
@@ -0,0 +1,31 @@
+/*\
+title: $:/core/modules/widgets/list/listviews/scroller.js
+type: application/javascript
+module-type: listview
+
+A list view that scrolls to newly inserted elements
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+var ScrollerListView = function(listWidget) {
+	this.listWidget = listWidget;
+}
+
+ScrollerListView.prototype.navigateTo = function(historyInfo) {
+	var listElementIndex = this.listWidget.findListElementByTitle(0,historyInfo.title),
+		listElementNode = this.listWidget.children[listElementIndex],
+		targetElement = listElementNode.domNode;
+	// Scroll the node into view
+	var scrollEvent = document.createEvent("Event");
+	scrollEvent.initEvent("tw-scroll",true,true);
+	targetElement.dispatchEvent(scrollEvent);
+};
+
+exports.scroller = ScrollerListView;
+
+})();
diff --git a/core/templates/PageTemplate.tid b/core/templates/PageTemplate.tid
index 4550a0b92..f89fd9a3f 100644
--- a/core/templates/PageTemplate.tid
+++ b/core/templates/PageTemplate.tid
@@ -24,7 +24,7 @@ title: $:/templates/PageTemplate
 </div>
 <div class="span10">
 <!-- The main display -->
-<$list filter="[list[$:/StoryList]]" history="$:/HistoryList" template="$:/templates/ViewTemplate" editTemplate="$:/templates/EditTemplate" listview=classic itemClass="tw-tiddler-frame"/>
+<$list filter="[list[$:/StoryList]]" history="$:/HistoryList" template="$:/templates/ViewTemplate" editTemplate="$:/templates/EditTemplate" listview="scroller" itemClass="tw-tiddler-frame"/>
 </div>
 </div>
 </div>