Display Empty View in Marionette CompositeView - backbone.js

I'm using a Marionette CompositeView to render an html table. Works great! Now I want to display a message when there are no records in the collection. I'm currently using the emptyView property to render this message. However, the message is rendered in the table wrapper and the tables column headers are still visible. Not exactly what I want. Ideally, I would like to hide/remove the table and display the empty records view and then show it when records are added. I'm struggling to find to best approach to handling this. Are there any suggestions out there?
EmptyView = Marionette.ItemView.extend({
template: "#empty-template"
});
SupportMemberView = Marionette.ItemView.extend({
template: "#member-template"
});
SupportTeamView = Marionette.CompositeView.extend({
template: "#support-team-template",
itemView: SupportMemberView,
emptyView: EmptyView,
itemViewContainer: 'tbody'
});

The accepted answer imposes a dependency between the empty view and the template, which does not feel right.
I think an alternative way to do this is to use dynamic templates in the composite view. This is done by overriding the base View getTemplate() method. Thus your composite view would be defined as follows, assuming you have access to the underscore.js library or equivalent to replace the "_.isEmpty()" function:
SupportTeamView = Marionette.CompositeView.extend({
getTemplate: function() {
if (_.isEmpty(this.collection)) {
return "#empty-template"
} else {
return "#support-team-template";
}
itemView: SupportMemberView,
emptyView: EmptyView,
itemViewContainer: 'tbody'
});

One thing that you can do is on your emprty View use the onRender function to hide the table. this function is called after the render function, so you will be able to manipulate the dom to look the way you want.

Related

Marionette and Backbone. Rendering javascript slider in View

This is the code:
NewEntry_CategoryView = Backbone.Marionette.ItemView.extend({
template: "#NewEntry_Category-template",
tagName: "p",
initialize: function () {
$("#sliderContainer").slider();
}
});
NewEntry_CategoriesView = Backbone.Marionette.CompositeView.extend({
template: "#NewEntry_Categories-template",
tagName: "div",
itemView: NewEntry_CategoryView,
itemViewContainer: '#categoryContainer',
appendHtml: function (collectionView, itemView) {
collectionView.$("#categoryContainer").append(itemView.el);
}
});
Why does the jquery ui slider not render when I show the NewEntry_CategoriesView ?
DOM events/manipulation like slide() won't have any effect on the view object's initialization because there is no such DOM element available yet.
Instead, you need to listen to dom:refresh of the view to manipulate its DOM element.
So, just put the code in onDomRefreshin your ItemView
onDomRefresh: function(){ $('#sliderContainer').slide() };
This above is a direct fix. But there are two more things to improve:
Don't call other div outside of this view when possible. In this case, if #sliderContainer belongs to another view, send an event to allow it slide itself. This is not the job of CategoryView. If it is inside current view, refer it with this.$el.find(".some-div") or better yet ui object.
Your collectionView's appendHtml is unnecessary. Marionette also takes of this common case.

How to update data after model fetch in Handlebars template with Backbone and Marionette?

Trying to have a data field in a Handlebars template update after the model that is assigned to the Marionette CompositeView is fetched, but the HTML in the page is not getting updated.
My code looks like this:
Model:
B.Page.Model = Backbone.Model.extend({
url: function () {
return 'my/resource/';
},
});
View:
B.Page.CompositeView = Backbone.Marionette.CompositeView.extend({
template: Handlebars.compile(templates.find('#my-template').html()),
initialize: function(options) {
_.bindAll(this);
this.model.fetch();
},
)};
Template:
<script id="my-template" type="text/x-handlebars-template">
Date: <span id="my-data-field">{{data}}</span>
</script>
I have checked the resource and it does return proper JSON with the data field set. Also, the model is getting passed in to the view.
I suspect that this is due to the render function not getting called after the data is retrieved; however, I would like to get feedback on how it should be done.
What is a good way to do this?
Thanks!
EDIT: This CompositeView does have a Collection that is associated with it (which renders just fine when I trigger the appropriate event). I purposefully left out that part of the code to avoid muddying up the problem.
Your are right, since a CompositeView extends from CollectionView, it only re-renders on collection events by default. To make it re-render on changes on your model, you could do something like this in your CompositeView:
initialize: function(){
this.listenTo(this.model, "change", this.render);
}
All Marionette views have a modelEvents object that is bound to the passed in model. So you could clean the accepted answer up slightly by doing:
template: Handlebars.compile(templates.find('#my-template').html()),
modelEvents: {
'change': 'render'
}
rather than binding manually in initialize.

Using Marionette.ItemView for views without models?

Is it conventional to use Marionette.ItemView for view classes that do not have a specific model property associated with them?
As Marionette.View is not meant to be used directly, it seems like an ItemView makes sense as a view class with convenient defaults and bindings.
Or, should one just resort to using Backbone.View? If so, is there a way to hook Backbone.View into Marionette's evented and garbage-collected architecture?
Thank you for clarification!
ItemView can be used without a model. I do this quite regularly.
If you need to specify data for an ItemView, but not have that data in a Backbone.Model, you need to override the serializeData method:
MyView = Marionette.ItemView.extend({
serializeData: function(){
return {
my: "custom data"
};
}
});
the base Marionette.View isnt' meant to be used directly because it doesn't provide a render function on it's own. That doesn't mean you can't use it to create your own base view types, though. You could, for example, build a view type for your application that deals with rendering google maps or a third party widget or something else that doesn't need the general Backbone.Model based rendering that ItemView has in it.
I just found out you can use a templateHelper for this - just chuck this in your ItemView declaration:
templateHelpers: function() {
return {
message: this.message,
cssClass: this.cssClass
}
}
And then in your template:
<script type="text/html" id="notice-template">
<span class="<%= cssClass %>"><%= message %></span>
</script>
And then when you initialise the view:
var noticeView = new App.Views.Notice();
noticeView.message = "HELLO";
App.noticeRegion.show(noticeView);
I would be interested in your thoughts on this Derick?

Backbone Marionette CompositeView Rendering/Usage

I must be doing something wrong because I can't get the non-collection portion of the CompositeView to render with a specified template. No matter how I try to specify the template, it doesn't render as expected.
Per the docs at https://github.com/derickbailey/backbone.marionette/blob/master/docs/marionette.compositeview.md
I've tried providing a string that points at a template stored in a script tag, and a pre-compiled template as the template argument like so:
Backbone.CompositeView.extend({
template: _.template( "<div><span class='items'></span></div>" )
});
Here's a live attempt in jsfiddle: http://jsfiddle.net/2PgrS/4/
You never rendered your view.
var view = new MyCompositeView({
collection: collection
});
// render the view
view.render();
view.$el.appendTo( "body" );
http://jsfiddle.net/derickbailey/XJLxv/1/

Backbone.js turning off wrap by div in render

I have model Post and collection Posts. And want to make form with list of all post in <select id="multi" multiple="multiple">. So i have to make a PostView render inside my #multi with just this template:
<option value=""><%= title %></option>
But finally I get it wrapped with div. Is there any solution for not wrapping this template with <div>?
If you don't define an el (or tagName) for the view (in the class or during instantiation) the view will be placed inside a div tag. http://documentcloud.github.com/backbone/#View-el
var PostView = Backbone.View.extend({
tagName: 'option'
});
UPDATE
Starting v0.9.0, Backbone has view.setElement(element) to get this done.
var PostView = Backbone.View.extend({
initialize: function() {
var template = _.template('<option value=""><%= title %></option>');
var html = template({title: 'post'});
this.setElement(html);
}
});
If you don't want to have the view wrap your HTML, you'll have to do a few things:
Replace this.el entirely
Call delegateEvents on the new el
render: function(){
var html = "some foo";
this.el = html;
this.delegateEvents(this.events);
}
Since Backbone generates a div or other tag (based on your tagName setting for the view), you have to replace it entirely. That's easy to do. When you do that, though, you lose your declared events because Backbone uses jQuery's delegate under the hood to wire them up. To re-enable your declared events, call delegateEvents and pass in your events declarations.
The result is that your view.el will be the <option> tag that you want, and nothing more.
In version 0.9.0, Backbone introduced view.setElement(element) to handle this operation.

Resources