iScroll scrollToElement not working with jQuery Mobile - jquery-mobile

I have something similar to this iScroll example: http://cubiq.org/dropbox/iscroll4/examples/simple/
Except that I'm using jQuery mobile (i.e., the header, footer, and content are set using jQuery Mobile). Everything is running smoothly except for scrollToElement.
Is there any way to get scrollToElement working when using jQuery Mobile and iScroll?
Here's the iScroll script I currently have:
var myScroll;
function loaded() {
myScroll = new iScroll('wrapper');
}
document.addEventListener('touchmove', function (e) { e.preventDefault(); }, false);
document.addEventListener('DOMContentLoaded', function () { setTimeout(loaded, 200);}, false);
EDIT: Forgot to mention what I'm trying to achieve. In the iScroll example mentioned above, I'm trying to scroll to a specific row. The only problem is that jQuery Mobile prevents scrollToElement from working for some reason.

Also make sure that you're using a timeout
setTimeout(function () {
myScroll.scrollToElement(".elementClass", "0s");
myScroll.refresh();
}, 0);

The workaround I have found is to capture the elements position and then use scrollToPage():
var w = $("#showselectedauthors").offset().top;
// ...
$.storeScroller.scrollToPage(0, w);
Of course for this to work you have to capture the position when the element is visible or the offset will be meaningless. You can do this when the page is built but before the scroller is initialized.
In my case the element is visible and I capture w at that time. I then refresh some content and refresh the scroller. After I do that I want to make sure the element is still visible.

Case anyone needs to scroll to a jQuery Object here's my code .
Make sure you're calling this method inside a setTimeout and your "iscroll" object is defined .
function scrollToElement($element) {
if ($element.size() > 1) {
throw new Error("Cannot be a node!");
};
var offset = $element.offset().top;
var to = -(offset - iscroll.y);
to = (iscroll.maxScrollY > to) ? iscroll.maxScrollY : to;
iscroll.scrollTo(0, to);
}

Related

How to refresh a page with Turbolinks

I understand that I can call the following code on Turbolinks 5 but it changes the scroll position. Is there a way to call Turbolinks to refresh the page and not change the scroll position?
Turbolinks.visit(location.toString());
This will do what I want, but was hoping to use Turbolinks
window.location.reload()
Store the current scroll position before calling visit, then when the page loads, scroll to that stored position. Resetting the stored scroll position to null ensures that subsequent page loads will not scroll to an old position. One possible implementation might be:
var reloadWithTurbolinks = (function () {
var scrollPosition
function reload () {
scrollPosition = [window.scrollX, window.scrollY]
Turbolinks.visit(window.location.toString(), { action: 'replace' })
}
document.addEventListener('turbolinks:load', function () {
if (scrollPosition) {
window.scrollTo.apply(window, scrollPosition)
scrollPosition = null
}
})
return reload
})()
Then you can call reloadWithTurbolinks().
To prevent the page from flickering as it scrolls from the top to the desired position, add the no-preview cache directive in the page's head:
<meta name="turbolinks-cache-control" content="no-preview">
It's bene a while, not sure if you would still need a solution. You can try this, which disable/enable scrolling before and after loading page content:
Turbolinks.enableTransitionCache(true);
Turbolinks.visit(location.toString());
Turbolinks.enableTransitionCache(false);
My answer is based on Dom Christie's answer, with restored focus after reload and getting the scrollPosition just before rendering.
Store the current scroll position and active field item before rendering the new page, then after the the is rendered, scroll to that stored position and restore the focus. Resetting the stored scroll position and focusId to null ensures that subsequent page loads will not scroll to an old position/ Focus.
Note that the fields must have assigned ids in order to recover the focus.
var reloadWithTurbolinks = (function () {
var scrollPosition;
var focusId;
function reload() {
Turbolinks.visit(window.location.toString(), {action: 'replace'})
}
document.addEventListener('turbolinks:before-render', function () {
scrollPosition = [window.scrollX, window.scrollY];
focusId = document.activeElement.id;
});
document.addEventListener('turbolinks:load', function () {
if (scrollPosition) {
window.scrollTo.apply(window, scrollPosition);
scrollPosition = null
}
if (focusId) {
document.getElementById(focusId).focus();
focusId = null;
}
});
return reload;
})();
Then you can call it like this:
setInterval(function () {
reloadWithTurbolinks();
}, 3000);
I combined it with the 'data-turbolinks-permanent' attribute on the form. I also use <meta name="turbolinks-cache-control" content="no-preview">.

Scrolling <div> in iOS causes div to blank out

I'm trying to handle a long list of <div>s and maintain scroll position in the list after navigating off and coming back. Essentially when a selection made is in the list I capture the listScrollPos and then try to reset it when I'm returning to the page (in Angular - so the list is re-rendered first).
vm.getAlbums = function() {
albumService.getAlbums()
.success(function (data) {
vm.albums = data;
$timeout(function () {
if (albumService.listScrollPos) {
$("#MainView").scrollTop(albumService.listScrollPos);
albumService.listScrollPos = 0;
}
}, 50); // delay required
})
.error(function(err) {
vm.error.error(err.message);
});
};
The process works fine in all browsers I tested - except on iOS in a WebView (Safari works fine). In other browsers the list displays and the scroll position is moved after the initial render. The pointer resets and all is good.
However, on iOS 8 either in Safari or a Web View in Cordova, the div turns white and shows 'empty'. If I touch the div anywhere it immediately displays at the correct scroll position.
IOW, the DOM appears to be updated and rendered, but the browser is somehow optimizing the scrolled content that was moved under program control.
Is there any way to force the browser to re-render the element after the scroll position was moved programmatically?
Ok, so after a bit more checking the problem is definitely isolated to the iOS WebView - Safari on iOS works fine without any of the following. But a Cordova app or a pinned iOS app exhibits this 'white out' behavior.
The workaround is to explicitly force the DOM to re-render the element using the 'scrollHeight reading trick'.
Here's the code that works:
vm.getAlbums = function() {
albumService.getAlbums()
.success(function (data) {
vm.albums = data;
setTimeout(function () {
if (albumService.listScrollPos) {
var el = $("#MainView");
el.scrollTop(albumService.listScrollPos);
albumService.listScrollPos = 0;
$timeout(function() {
var t = el[0].scrollHeight;
}, 1);
}
}, 1); // delay around animation 900
})
};
Notice the last $timeout() block that simply reads the scrollHeight of the element, which forces the re-render and properly displays the result.
There's a little jumpiness due to the slight rendering delay.

jQuery mobile listviews lazy loading

How can i implement lazy loading in mobile jquery lisview widget?
can anybody give a example using static data in json format binding to jquery mobile listview widget?
Thank you.
There are a few ways, The following two ways work great
JQM way, a great tutorial. It detects when you scrolled to the bottom of the listview and loads more items to list
http://jqmtricks.wordpress.com/2014/07/15/infinite-scrolling/
Demo
http://jsfiddle.net/Palestinian/pAgbT/light/
Another way is to use Iscroll 5 plugging. Similarly you can setup a function to detect when you scrolled to the bottom of the list and load new items
http://iscrolljs.com/
Demo I placed the whole Iscroll 5 plugging in the demo so scroll down to //// JQM STUFF to see the actual code
Some of the JQM code e.g trigger create is depreciated in JQM 1.4 so some modifications are needed above > 1.4 for it work.
http://jsfiddle.net/t0t3Lz5x/
var myScroll;
$(document).ready(function(){
myScroll = new IScroll('#wrapper',
{
scrollX: false,
scrollY: true
,click:true // open click event
,scrollbars: false
,useTransform: true
,useTransition: false
,probeType:3,
mouseWheel:true,
bindToWrapper: true
});
});
function initscroll() {
setTimeout(function () {
myScroll.refresh();
}, 1000);
}
output = '<li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li><li><a>Item</a></li>';
$('#listview').html(output).listview().listview('refresh');
initscroll()
myScroll.on('scrollEnd', function() {
if (this.y == this.maxScrollY)
load_new_items();
});
function load_new_items() {
mysearchlist = $('<li><a>New Item</a></li><li><a>New Item</a></li><li><a>New Item</a></li><li><a>New Item</a></li>');
mysearchlist.appendTo("#listview").trigger('create');
$('#listview').listview().listview('refresh');
initscroll()
}
There is one more way using the Jquery's on scroll function to monitor the height of the list and then as you scroll measure the pixels you scrolled from the top of the list. When both match you can run a function to append more items in the list

How to set nothing on el or tagname to work with jquery ui accordion

Structure of jQueryUI's Accordion is something like this,
<h2>title</h2><div>content</div>
for each item. What I am going to do is create accordion inside of my backbone view through looping, but backbone create div tag for each item so I have html code like this
<div><h2>title</h2><div>content</div></div>
This makes jQuery Accordion control does not work correctly, collapse and expand is not working.
I think this can be solved if I can set nothing on el or tagname, but I cannot find out.
Is there any way to solve this problem?
I think you'd be better off leaving the accordion to one view and then have a separate view inside each panel. After all, the <h2>s are controls for the accordion as-a-whole rather than for a specific panel.
You'd have some per-panel views like this:
var P = Backbone.View.extend({
render: function() {
// Add the panel's content to this.$el (which is a <div> by default).
return this;
}
});
And then an accordion view like this:
var A = Backbone.View.extend({
render: function() {
var panels = [ ... ];
for(var p, i = 0; i < panels.length; ++i) {
p = new P({ ... });
this.$el.append('<h3><a>' + panels[i] + '</a></h3>');
this.$el.append(p.render().el);
}
// The accordion wants to know the sizes of things so
// we let the DOM sort itself out before binding the
// accordion.
var _this = this;
setTimeout(function() { _this.$el.accordion() }, 0);
return this;
}
});
Then you can simply $('#something').append((new A).render().el) and it all works out nicely while leaving everything where it should be.
You could also add a title method to the P views and then A could ask the panel what its name/title/header should be so that all the per-panel information is nicely contained in the per-panel view.
Demo: http://jsfiddle.net/ambiguous/Y49W8/

Preventing flexcroll on event

What I have currently is a very simple div that has a flexcroll scroll bar. This simple div contains some draggable itmes inside of it. My goal is to be able to drag one of the items and and move it about without the flexcroll scroll bar moving.
As it stands right now if I were to drag one of the items below the viewable area the simple div will scroll down. I would like to prevent this.
I'm using jQuery UI for the draggable items. I've already tried using the option "scroll:false" but this does not work for flexcroll.
I'm sorry I don't have any example code, I'm currently away from my work computer.
flexcroll: http://www.hesido.com/web.php?page=customscrollbar
I don't know if you have already resolved this problem. This morning, I have the same problem and I found your post. After that, I have googled a lot to find a solution without any lucky. So finally, I decided to do someting myself, I hope my idea will help you.
After read the Programming Guid, I found that in this version (2.0) of flexcroll, we could register a function for onfleXcroll whose description could be found by searching the keyword "Pseudo-event: onfleXcroll". This is to say that the method will be executed after a scroll is done. So here, what I restore the "top" style with the value before you drag an element.
Here are the code
var $assetswrapper; // This variable indicates the contentwrapper of you div.
var $assetsscrollbar; // This variable indicates the vscroller of you div.
window.onfleXcrollRun = function () { // This method will be executed as soon as the div has been rendered with the help of flexcroll
// You could find these two divs by using firebug, because the top value of these two divs will be changed when we scroll the div which use the class .flexcroll.
$assetswrapper = $('#contentwrapper');
$assetsscrollbar = $('#vscrollerbar');
}
var wrapperTopPosition = 0; // This is used to stock the top value of the wrapperContent before dragging.
var scrollbarTopPosition = 0; // This is used to stock the top value of the scrollbar before dragging.
var dragged; // This is a boolean variable which is used for indicating whether the draggable element has been dragged.
var dropped = false; // This is a boolean variable which used to say whether the draggable element has been dropped.
$('.draggable').draggable({ // you could change .draggable with any element.
start: function (event, ui) {
// Your code here.
wrapperTopPosition = $assetswrapper.position().top;
scrollbarTopPosition = $assetsscrollbar.position().top
dragged = true;
},
stop: function (event, ui) {
// Your code here.
dragged = false;
dropped = true;
}
});
$('your drag div')[0].onfleXcroll = function () { // This method will be called each time when a scroll has been done.
if (dragged) {
$assetswrapper.css('top', wrapperTopPosition);
$assetsscrollbar.css('top', scrollbarTopPosition);
} else {
// Code here is used for keeping the top position as before even though you have dragged an element out of this div for a long time.
// You could test the scrollbar without this piece of code, if you drag an element out of the div for a long time, the scrollbar will keep its position,
// but after you dropped this element and try to scroll the div, then the scrollbar will reach the end of the div. To solve this problem,
// I have introduced the method setScrollPos with the old top position plus 72. 72 here is to set the scroll increment for this scroll, I know
// this value is not fit for any size of windows, but I don't know how to get the scroll-increment automatically.
if (dropped) {
dropped = false;
$('your drag div')[0].fleXcroll.setScrollPos(false, Math.abs(wrapperTopPosition) + 72);
$('your drag div')[0].fleXcroll.setScrollPos(false, Math.abs(wrapperTopPosition) + 72);
}
}
};
I hope this could give you a help if you haven't found any solution yet.

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