backbone view passed to jQuery Mobile - jquery-mobile

Question

I've been trying to use backbonejs and jqm together.
I can render the main page alright. The page has a list that the user can tap on. The item selected should show a detail page with info on the list item selected. The detail page is a backbone view with a template that's rendered in the item's view object.
The detail's view .render() produces the html ok and I set the html of the div tag of the main page to the rendered item's detail markup. It looks like this:
podClicked: function (event) {
console.log("PodListItemView: got click from:" + event.target.innerHTML + " id:" + (this.model.get("id") ? this.model.get("id") : "no id assigned") + "\n\t CID:" + this.model.cid);
var detailView = new PodDetailView({ model: this.model });
detailView.render();
},
The detail view's render looks like this:
render: function () {
this.$el.html(this.template({ podId: this.model.get("podId"), isAbout_Name: this.model.get("isAbout_Name"), happenedOn: this.model.get("happenedOn") }));
var appPageHtml = $(app.el).html($(this.el));
$.mobile.changePage(""); // <-- vague stab in the dark to try to get JQM to do something. I've also tried $.mobile.changePage(appPageHtml).
console.log("PodDetailView: render");
return this;
}
I can see that the detail's view has been rendered on the page by checking Chrome's dev tools html editor but it's not displaying on the page. All I see is a blank page.
I've tried $.mobile.changePage() but, without an URL it throws an error.
How do I get JQM to apply it's class tags to the rendered html?
the HTML and templates look like this:
<!-- Main Page -->
<div id="lessa-app" class="meditator-image" data-role="page"></div>
<!-- The rest are templates processed through underscore -->
<script id="app-main-template" type="text/template">
<div data-role="header">
<h1>#ViewBag.Title</h1>
</div>
<!-- /header -->
<div id="main-content" data-role="content">
<div id="pod-list" data-theme="a">
<ul data-role="listview" >
</ul>
</div>
</div>
<div id="main-footer" data-role='footer'>
<div id="newPod" class="ez-icon-plus"></div>
</div>
</script>
<script id="poditem-template" type="text/template">
<span class="pod-listitem"><%= isAbout_Name %></span> <span class='pod-listitem ui-li-aside'><%= happenedOn %></span> <span class='pod-listitem ui-li-count'>5</span>
</script>
<script id="page-pod-detail-template" type="text/template">
<div data-role="header">
<h1>Pod Details</h1>
</div>
<div data-role="content">
<div id='podDetailForm'>
<fieldset data-role="fieldcontain">
<legend>PodDto</legend>
<label for="happenedOn">This was on:</label>
<input type="date" name="name" id="happenedOn" value="<%= happenedOn %>" />
</fieldset>
</div>
<button id="backToList" data-inline="false">Back to list</button>
</div>
<div data-role='footer'></div>
</script>
Thanks in advance for any advice... is this even doable?

Answer 1

I've finally found a way to do this. My original code has several impediments to the success of this process.
The first thing to do is to intercept jquerymobile's (v.1.2.0) changePage event like this:
(I've adapted the outline from jqm's docs and left in the helpful comments: see http://jquerymobile.com/demos/1.2.0/docs/pages/page-dynamic.html
)
$(document).bind("pagebeforechange", function (e, data) {
// We only want to handle changePage() calls where the caller is
// asking us to load a page by URL.
if (typeof data.toPage === "string") {
// We are being asked to load a page by URL, but we only
// want to handle URLs that request the data for a specific
// category.
var u = $.mobile.path.parseUrl(data.toPage),
re = /^#/;
// don't intercept urls to the main page allow them to be managed by JQM
if (u.hash != "#lessa-app" && u.hash.search(re) !== -1) {
// We're being asked to display the items for a specific category.
// Call our internal method that builds the content for the category
// on the fly based on our in-memory category data structure.
showItemDetail(u, data.options); // <--- handle backbone view.render calls in this function
// Make sure to tell changePage() we've handled this call so it doesn't
// have to do anything.
e.preventDefault();
}
}
});
The changePage() call is made in the item's list backbone view events declaration which passes to the podClicked method as follows:
var PodListItemView = Backbone.View.extend({
tagName: 'li', // name of (orphan) root tag in this.el
attributes: { 'class': 'pod-listitem' },
// Caches the templates for the view
listTemplate: _.template($('#poditem-template').html()),
events: {
"click .pod-listitem": "podClicked"
},
initialize: function () {
this.model.bind('change', this.render, this);
this.model.bind('destroy', this.remove, this);
},
render: function () {
this.$el.html(this.listTemplate({ podId: this.model.get("podId"), isAbout_Name: this.model.get("isAbout_Name"), happenedOn: this.model.get("happenedOn") }));
return this;
},
podClicked: function (event) {
$.mobile.changePage("#pod-detail-page?CID='" + this.model.cid + "'");
},
clear: function () {
this.model.clear();
}
});
In the 'showItemDetail' function the query portion of the url is parsed for the CID of the item's backbone model. Again I've adapted the code provided in the jquerymobile.com's link shown above.
Qestion: I have still figuring out whether it's better to have the code in showItemDetail() be inside the view's render() method. Having a defined function seems to detract from backbone's architecture model. On the other hand, having the render() function know about calling JQM changePage seems to violate the principle of 'separation of concerns'. Can anyone provide some insight and guidance?
// the passed url looks like #pod-detail-page?CID='c2'
function showItemDetail(urlObj, options) {
// Get the object that represents the item selected from the url
var pageSelector = urlObj.hash.replace(/\?.*$/, "");
var podCid = urlObj.hash.replace(/^.*\?CID=/, "").replace(/'/g, "");
var $page = $(pageSelector),
// Get the header for the page.
$header = $page.children(":jqmData(role=header)"),
// Get the content area element for the page.
$content = $page.children(":jqmData(role=content)");
// The markup we are going to inject into the content area of the page.
// retrieve the selected pod from the podList by Cid
var selectedPod = podList.getByCid(podCid);
// Find the h1 element in our header and inject the name of the item into it
var headerText = selectedPod.get("isAbout_Name");
$header.html("h1").html(headerText);
// Inject the item info into the content element
var view = new PodDetailView({ model: selectedPod });
var viewElHtml = view.render().$el.html();
$content.html(viewElHtml);
$page.page();
// Enhance the listview we just injected.
var fieldContain = $content.find(":jqmData(role=listview)");
fieldContain.listview();
// We don't want the data-url of the page we just modified
// to be the url that shows up in the browser's location field,
// so set the dataUrl option to the URL for the category
// we just loaded.
options.dataUrl = urlObj.href;
// Now call changePage() and tell it to switch to
// the page we just modified.
$.mobile.changePage($page, options);
}
So the above provides the event plumbing.
The other problem I had was that the page was not set up correctly. It's better to put the page framework in the main html and not put it in an underscore template to be rendered at a later time. I presume that avoids issues where the html is not present when jqm takes over.
<!-- Main Page -->
<div id="lessa-app" data-role="page">
<div data-role="header">
<h1></h1>
</div>
<!-- /header -->
<div id="main-content" data-role="content">
<div id="pod-list" data-theme="a">
<ul data-role="listview">
</ul>
</div>
</div>
<div id="main-footer" data-role='footer'>
<div id="main-newPod" class="ez-icon-plus"></div>
</div>
</div>
<!-- detail page -->
<div id="pod-detail-page" data-role="page">
<div data-role="header">
<h1></h1>
</div>
<div id="detail-content" data-role="content">
<div id="pod-detail" data-theme="a">
</div>
</div>
<div id="detail-footer" data-role='footer'>
back
</div>
</div>