Move client/{base, observable, layout, touch, util, view} to samples/ui_lib .

client/touch/InfiniteScroller.dart

Index: client/touch/InfiniteScroller.dart
===================================================================
--- client/touch/InfiniteScroller.dart	(revision 4144)
+++ client/touch/InfiniteScroller.dart	(working copy)
@@ -1,145 +0,0 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-/**
- * Adds a listener to the scroller with triggers events
- * when a trigger point at the top, or bottom, of the screen is reached.
- *
- * To use this you will need to have an element with a scroller attached
- * to it. You need to have defined (in pixels) how far from the top or
- * bottom the scroll position must be in order to trigger (the "trigger
- * point") The element using this must have functions for hitting the top
- * trigger, and the bottom trigger. In general, these methods will
- * ascertain whether we have more data to scroll to (i.e. when we hit
- * the bottom trigger point but have reached the end of the data
- * displayed in the element we should ignore it), make the call for
- * more data and reposition the scroller - repositioning is key to
- * good user experience.
- *
- * Triggers are generated by listening for the SCROLL_END event from the
- * scroller, so data calls are not initiated whilst scrolling is happening,
- * but after.
- *
- * Controls changing divs between the usual (non-loading) div and the
- * loading div. To take advantage of this, callback function should return
- * a boolean indicating whether the usual div should be replaced by the
- * loading div.
- */
-class InfiniteScroller {
-  Scroller _scroller;
-
-  /**
-   * Function to invoke when trigger point is reached at the top of the view.
-   */
-  Function _onTopScroll;
-
-  /**
-   * Function to invoke when trigger point is reached at the bottom of the view.
-   */
-  Function _onBottomScroll;
-
-  /** Offset for trigger point at the top of the view. */
-  double _offsetTop;
-
-  /** Offset for trigger point at the bottom of the view. */
-  double _offsetBottom;
-
-  /** Saves the last Y position. */
-  double _lastScrollY;
-  Element _topDiv;
-  Element _topLoadingDiv;
-  Element _bottomDiv;
-  Element _bottomLoadingDiv;
-
-  InfiniteScroller(Scroller scroller,
-                   Function onTopScroll, Function onBottomScroll,
-                   double offsetTop, [double offsetBottom = null])
-      : _scroller = scroller,
-        _onTopScroll = onTopScroll,
-        _onBottomScroll = onBottomScroll,
-        _offsetTop = offsetTop,
-        _offsetBottom = offsetBottom == null ? offsetTop : offsetBottom,
-        _lastScrollY = 0.0 {
-  }
-
-  /**
-   * Adds the loading divs.
-   * [topDiv] The div usually shown at the top.
-   * [topLoadingDiv] is the div to show at the top when waiting for more
-   * content to load at the top of the page.
-   * [bottomDiv] is the div usually shown at the bottom.
-   * [bottomLoadingDiv] is the div to show at the bottom when waiting for more
-   * content to load at the end of the page.
-   */
-  void addLoadingDivs([Element topDiv = null,
-                       Element topLoadingDiv = null,
-                       Element bottomDiv = null,
-                       Element bottomLoadingDiv = null]) {
-    _topDiv = topDiv;
-    _topLoadingDiv = topLoadingDiv;
-    _bottomDiv = bottomDiv;
-    _bottomLoadingDiv = bottomLoadingDiv;
-    _updateVisibility(false, _topDiv, _topLoadingDiv);
-    _updateVisibility(false, _bottomDiv, _bottomLoadingDiv);
-  }
-
-  void initialize() {
-    _registerEventListeners();
-  }
-
-  /**
-   * Switch back the divs after loading complete. Delegate should call
-   * this function after loading is complete.
-   */
-  void loadEnd() {
-    _updateVisibility(false, _topDiv, _topLoadingDiv);
-    _updateVisibility(false, _bottomDiv, _bottomLoadingDiv);
-  }
-
-  /**
-   * Called at the end of a scroll event.
-   */
-  void _onScrollEnd() {
-    double ypos = _scroller.getVerticalOffset();
-
-    // Scroll is below last point.
-    if (ypos < _lastScrollY) {
-      double bottomTrigger = _scroller.getMinPointY() + _offsetBottom;
-      // And below trigger point.
-      if (ypos <= bottomTrigger) {
-        _updateVisibility(_onBottomScroll(), _bottomDiv, _bottomLoadingDiv);
-      }
-    } else {
-      if (ypos > _lastScrollY) {
-        // Scroll is above last point.
-        double topTrigger = _scroller.getMaxPointY() - _offsetTop;
-        // And above trigger point.
-        if (ypos >= topTrigger) {
-          _updateVisibility(_onTopScroll(), _topDiv, _topLoadingDiv);
-        }
-      }
-    }
-    _lastScrollY = ypos;
-  }
-
-  /**
-   * Register the event listeners.
-   */
-  void _registerEventListeners() {
-    _scroller.onScrollerEnd.add((Event event) { _onScrollEnd(); });
-  }
-
-  /**
-   * Hides one div and shows another.
-   */
-  void _updateVisibility(bool isLoading, Element element,
-                         Element loadingElement) {
-    if (element != null) {
-      element.style.display = isLoading ? "none" : "";
-    }
-    if (loadingElement != null) {
-      loadingElement.style.display = isLoading ? "" : "none";
-    }
-  }
-}