The new Waypoints feature looks nice. I wonder if there are some useful but
missing pieces, though, Let's say you've set a waypoint at 75% in order to
load additional data at the end, to implement infinite scrolling. The user
then scrolls past 75%, causing the event whose handler requests more data.
Before the new data has arrived, the user scrolls backwards (towards the
beginning of the list) so again passes the 75% waypoint, which again
requests yet more data. The second of those events should not have
requested more data at the end because the user is scrolling towards the
beginning.
It seems that two changes would be useful:
1. In the setWaypointsY() method, allow specifying whether a waypoint event
should be generated when passing the waypoint scrolling down, up, or
either. One possible implementation is:
scrollContainer.setWaypointsY(
[
"0%",
{ waypoint : "25%", activatedOn : "scrolldown" },
"50%",
{ waypoint : "75%", activatedOn : "scrollup" },
{ waypoint : "100%", activatedOn : "scrollupdown" },
200,
".waypoint"
]);
which would activate the 25% waypoint event only when scrolling down; the
75% waypoint only when scrolling up; and all others when scrolling in
either direction. (Note that the map can be used for events for either
direction, as with 100%, or the map can be excluded in those cases, as with
50%.)
Additionally, the event payload can indicate which direction scrolling has
occurred:
{
"offset": 0,
"input": "10%",
"index": 0,
"element" : 0,
"direction" : "scrolldown"
}
For your consideration,
Derrell
On Fri, Aug 15, 2014 at 8:07 AM, qooxdoo News <webmas...@qooxdoo.org> wrote:
> qooxdoo News <http://news.qooxdoo.org>
> ------------------------------
>
> The week in qooxdoo (2014-08-15)
> <http://feedproxy.google.com/~r/qooxdoo/news/content/~3/pJY5EALvcIc/the-week-in-qooxdoo-2014-08-15?utm_source=feedburner&utm_medium=email>
>
> Posted: 15 Aug 2014 04:56 AM PDT
>
> This week, we have been busy in the mobile part of the framework, as you
> might have already read in our separate blog post
> <http://news.qooxdoo.org/waypoints-feature-added-to-qx-mobile> about the
> new waypoint feature. This is a handy new feature you might want to try in
> the playground <http://tinyurl.com/llp9yef> for yourself. This also
> enables you to implement a commonly used pattern called *pull to refresh
> <http://bugzilla.qooxdoo.org/show_bug.cgi?id=8535>*.
>
> We have also been busy in refactoring the picker widget
> <http://demo.qooxdoo.org/devel/mobileshowcase/index.html#%2Fdialog>, but
> more details on that will be covered in a blog post coming next week.
>
> For a complete list of all tasks accomplished during the last working
> week, see this bugzilla query
> <http://bugzilla.qooxdoo.org/buglist.cgi?query_format=advanced&resolution=FIXED&chfieldfrom=2014-08-08&chfieldto=2014-08-15&chfield=resolution>
> .
>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:yIl2AUoC8zA>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:D7DqB2pKExk>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:dnMXMwOfBR0>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:V_sGLiPBpWU>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:F7zBnMyn0Lo>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:gIN9vFwOqvQ>
> <http://feeds.feedburner.com/~ff/qooxdoo/news/content?a=pJY5EALvcIc:muaGoYpD-8c:qj6IDK7rITs>
>
> Waypoints feature added to qx.Mobile
> <http://feedproxy.google.com/~r/qooxdoo/news/content/~3/ssSDrS7IFHs/waypoints-feature-added-to-qx-mobile?utm_source=feedburner&utm_medium=email>
>
> Posted: 14 Aug 2014 08:16 AM PDT
>
> <http://demo.qooxdoo.org/devel/mobileshowcase/index.html#%2Flist>We
> enhanced the qx.Mobile pageEnd logic and added a scroll waypoint feature.
> It makes it possible to execute code whenever you scroll to a pre-defined
> offset. This is very useful if you want to trigger an animation/action when
> the user scrolls to specified vertical/horizontal point. This feature is
> also necessary if you want to implement infinite scrolling.
>
> The waypoint feature can be used like this:
>
> var scrollContainer = page._getScrollContainer();
> scrollContainer.setWaypointsY(["0%","50%","100%",200,".waypoint"]);
>
> You can add percentage-based waypoints by adding a string like "20%" or
> just add numbers for applying pixel-based offsets. Additionally you can
> determine waypoints through a CSS selector query
> <https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_Started/Selectors>
> .
>
> Whenever a waypoint triggers, a qx.event.type.Data fires on the scroll
> container:
>
> scrollContainer.addListener("waypoint", function(evt) {
> console.log("Waypoint reached:" + evt.getData());
> }, this);
>
> The payload of the waypoint event looks like this:
>
> {
> "offset": 0,
> "input": "10%",
> "index": 0,
> "element" : 0
> }
>
>
> - offset contains the scroll offset in pixel.
> - input is the waypoint condition you passed through the array and
> which triggered this event.
> - index identifies this waypoint relative to its position inside the
> waypoint array you have passed.
> - element contains the element index found through your selector. e.g.
> you have five elements with ‘.waypoint’ class inside your scroll container,
> and user scrolls to the fifth element with this identifier, then element
> would be 4. This value is only relevant for waypoint rules based upon a
> selector. For numbers and percentage-based rules it is always null.
>
> Have a look at this feature at the qx.Mobile List demo
> <http://demo.qooxdoo.org/devel/mobileshowcase/index.html#%2Flist> or
> check out the demo source code
> <https://github.com/qooxdoo/qooxdoo/blob/master/application/mobileshowcase/source/class/mobileshowcase/page/List.js>
> .
>
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