I have two different view (1), (2)
1) it shows the list of users
2) it shows the detail of users
In the (2) is possible to change the name.
Then I would expect that the correspondent item in the (1) change accordingly, but it does not.
How should fix/debug the problem?
Here my essential code:
// list of users (1)
View_1 = Backbone.View.extend({
collection: new MyCollection(),
initialize: function () {
this.collection.bind('add', this.addOne);
this.collection.bind('reset', this.addAll);
}
});
// user detail (2)
View_2 = Backbone.View.extend({
model: new MyModel()
});
MyCollection = Backbone.Collection.extend({
model: new MyModel()
});
You need to bind a change event to the collection. Right now you only bind reset and add, so things will only update when a new model is added to the collection, or when the collection is initialized with starting values.
this.collection.bind('change', this.render);
Or something like that, to trigger rendering whatever needs to change.
Related
I have a collection of items. I would like to keep track of the current selection. When the user clicks on a different item in the collection, I want to indicate that the item is selected and display the details of the selected item. Think of this as a list with a detail view (like a typical email client).
Example of a master-detail layout (source):
I currently have something like this (written in CoffeeScript, templates use haml-coffee):
class Collections.Items extends Backbone.Collection
model: Models.Item
setCurrentSelection: (id)->
# what to do here? Is this even the right way to do it?
getCurrentSelection: ->
# what to do here? Is this even the right way to do it?
class Views.ItemsPage extends Backbone.View
list_template: JST['items/list']
details_template: JST['items/details']
events:
'click .item': 'updateSelection'
initialize: (options)->
#collection = options.collection
render: ->
$('#items_list').html(#list_template(collection: #collection.toJSON())) # not sure if this is how to render a collection
$('#item_details').html(#details_template(item: #collection.currentSelection().toJSON())) # how to implement currentSelection?
#
updateSelection: (event)->
event.preventDefault()
item_id = $(event.currentTarget).data('id')
# mark the item as selected
# re-render using the new selection
# templates/items/list.hamlc
%ul
- for item in #collection
%li{data:{id: item.id}, class: ('selected' if item.selected?)} # TODO: How to check if selected?
= item.name
# templates/items/details.hamlc
%h2= #item.name
I'm not sure if I'm following you (my CoffeeScript is a bit rusty), but I think what you're trying to do is set a selected property on the appropriate model in your updateSelection method, and then re-render your view.
In other words:
updateSelection: (event)->
event.preventDefault()
item_id = $(event.currentTarget).data('id')
model = this.collection.get(item_id) # get the model to select
model.selected = true # mark the item as selected
this.render() # re-render using the new selection
even saying "my CoffeeScript is a bit rusty" is too much for me. But i'll still attempt to explain as best as i can in js.
First the backbone way is to keep models as a representation of a REST resource document. (server side - persisted data).
Client side presentation logic should stick to views. to remember which list item is visible in in the details part is job of the that specific view. initiating change request for details view model is job of the list of items.
the ideal way is to have two separate views for list and details. (you can also go a bit more ahead and have a view for every item in the list view.
parent view
var PageView = Backbone.View.extend({
initialize: function() {
//initialize child views
this.list = new ItemListView({
collection : this.collection //pass the collection to the list view
});
this.details = new ItemDetailView({
model : this.collection.at(1) //pass the first model for initial view
});
//handle selection change from list view and replace details view
this.list.on('itemSelect', function(selectedModel) {
this.details.remove();
this.details = new ItemDetailView({
model : selectedModel
});
this.renderDetails();
});
},
render: function() {
this.$el.html(this.template); // or this.$el.empty() if you have no template
this.renderList();
this.renderDetails();
},
renderList : function(){
this.$('#items_list').append(this.list.$el); //or any other jquery way to insert
this.list.render();
},
renderDetails : function(){
this.$('#item_details').append(this.details.$el); //or any other jquery way to insert
this.details.render();
}
});
list view
var ItemListView = Backbone.View.extend({
events : {
'click .item': 'updateSelection'
},
render: function() {
this.$el.html(this.template);
this.delegateEvents(); //this is important
}
updateSelection : function(){
var selectedModel;
// a mechanism to get the selected model here - can be same as yours with getting id from data attribute
// or you can have a child view setup for each model in the collection. which will trigger an event on click.
// such event will be first captured by the collection view and thn retriggerd for page view to listen.
this.trigger('itemSelect', selectedModel);
}
});
details view
var ItemDetailView = Backbone.View.extend({
render: function() {
this.$el.html(this.template);
this.delegateEvents(); //this is important
}
});
This won't persist the state through routes if you don't reuse your views. in that case you need to have a global state/event saving mechanism. somthing like following -
window.AppState = {};
_.extend(window.AppState, Backbone.Events);
//now your PageView initilize method becomes something like this -
initialize: function() {
//initialize child views
this.list = new ItemListView({
collection : this.collection //pass the collection to the list view
});
var firstModel;
if(window.AppState.SelectedModelId) {
firstModel = this.collection.get(window.AppState.SelectedModelId);
} else {
firstModel = this.collection.at(1);
}
this.details = new ItemDetailView({
model : firstModel //pass the first model for initial view
});
//handle selection change from list view and replace details view
this.list.on('itemSelect', function(selectedModel) {
window.AppState.SelectedModelId = selectedModel.id;
this.details.remove();
this.details = new ItemDetailView({
model : selectedModel
});
this.renderDetails();
});
}
EDIT
Handling selected class (highlight) in list view . see comments for reference.
list view template -
<ul>
<% _.each(collection, function(item, index){ %>
<li data-id='<%= item.id %>'><%= item.name %></li>
<% }); %>
</ul>
inside list view add following method -
changeSelectedHighlight : function(id){
this.$(li).removeClass('selected');
this.$("[data-id='" + id + "']").addClass('selected');
}
simply call this method from updateSelection method and during PageView initialize.
this.list.changeSelectedHighlight(firstModel.id);
Let's say I have some items to show in a list. The list has a view that aggregates all the items as item views. Now I want to handle the click events on the item views and I delegate the handling to the list view.
Let's see some example code:
ItemView = Backbone.View.extend({
className: 'item',
initialize: function() {
this.$el.data('backbone-view', this);
}
});
Note that I am attaching the view object itself as a property of the root element, which essentially creates a circular reference situation for the view and the element.
ListView = Backbone.View.extend({
initialize: function() {
// contains the item views
this.items = [];
// click event delegation
this.$el.click(_.bind(this._onClick, this));
},
addItem: function(v) {
if ( !(v instanceof ItemView) ) return;
this.items.push(v);
this.$el.append(v.el);
},
_onClick: function(e) {
var el = $(e.target).closest('.item'),
view = el.data('backbone-view');
// do something with the view
}
});
This is a very general pattern whenever one has to deal with any kind of list views.
I am getting the item view back in the handler via the data property that I set on the item on the initialization time. I need to get item view because anything that I want to do on the item as part of handling the click event is based on the view.
Also note that I am using closest because item view may be complex and the actual target of the click event may be a descendant of the root element.
So the question: is this way to binding the view to it's root element via data properties the right approach -- in particular when considering garbage collection and memory leaks? Can there be something better than this?
You should catch the events in the child view. In my opinion, any Backbone view should only handle the DOM events of its element and its children. If views are nested, as yours are, the most specific view should handle the events.
If you want to delegate handling to the parent view, you can trigger a backbone event in the ItemView, and listen to those in the ListView.
ItemView = Backbone.View.extend({
events: {
"click":"onClick"
},
onClick: function() {
//trigger a custom event, passing the view as first argument
this.trigger('click', this);
}
});
ListView = Backbone.View.extend({
addItem: function(v) {
if ( !(v instanceof ItemView) ) return;
//listen to custom event
this.listenTo(v, 'click', this._onClick);
this.items.push(v);
this.$el.append(v.el);
},
_onClick:function(itemView) {
//...
}
});
If the click event represents some "higher level" action, such as select or activate, you should name your custom events as such. This way you can create a logical, robust interface between your views without concerning the parent ListView with the implementation details of its child. Only ItemView should know that whether it's been clicked, hovered, double clicked etc.
I have an edit view for a Backbone Model that I create each time the the element is clicked on. The problem I have is that the edit view needs two Backbone collections to create the edit form (it contains two <select> lists).
The view:
MyApp.elementView = Backbone.View.extend({
events: {
'click .edit': 'editForm',
},
editForm: function(ev) {
var editView = new TimeTrack.Views.EditJob({
model: this.model
// This view needs two more collections
// for the <select> elements
});
...
}
});
Instantiate the view:
var elementView = new MyApp.elementView({
collection: elementCollection
});
What is the best way to push the needed collections to the edit view? Do I have to pass the collections need for the edit view from the elementView form the instantiation? Or is there a better way of doing this?
I did so, passed in view 2 collections, 1 - the main and the other as follows:
to elementView - second collection and in elementView recive her.
example:
in router I'm
initialize: ->
(YourNameSpace).secondCollection = new (YourNameSpace).secondCollection
elements: =>
view = new (YourNameSpace).elementView( secondCollection: #secondCollection )
$('.l-yield').html(view.render().el)
Here is my situation. I have a bunch of "Question" model inside a "Questions" collection.
The Question Collection is represented by a SurveyBuilder view.
The Question Model is represented by a QuestionBuilder view.
So basically you have an UL of QuestionBuilder views. The UL has a jQuery sortable attached (so you can reorder the questions). The question is once I'm done reordering I want to update the changed "question_number"s in the models to reflect their position.
The Questions collection has a comparator of 'question_number' so collection should be sorted. Now I just need a way to make their .index() in the UL reflect their question_number. Any ideas?
Another problem is DELETEing a question, I need to update all the question numbers. Right now I handle it using:
var deleted_number = question.get('question_number');
var counter = deleted_number;
var questions = this.each(function(question) {
if (question.get('question_number') > deleted_number) {
question.set('question_number', question.get('question_number') - 1);
}
});
if (this.last()) {
this.questionCounter = this.last().get('question_number') + 1;
} else {
this.questionCounter = 1;
}
But it seems there's got to be a much more straighforward way to do it.
Ideally whenever a remove is called on the collection or the sortstop is called on the UL in the view, it would get the .index() of each QuestionuBuilder view, update it's models's question_number to the .index() + 1, and save().
My Models,Views, and Collections: https://github.com/nycitt/node-survey-builder/tree/master/app/js/survey-builder
Screenshot: https://docs.google.com/file/d/0B5xZcIdpJm0NczNRclhGeHJZQkE/edit
More than one way to do this but I would use Backbone Events. Emit an event either when the user clicks something like done sorting, hasn't sorted in N seconds, or as each sort occurs using a jQuery sortable event such as sort. Listen for the event inside v.SurveyBuilder.
Then do something like this. Not tested obviously but should get you there relatively easily. Update, this should handle your deletions as well becuase it doesn't care what things used to be, only what they are now. Handle the delete then trigger this event. Update 2, first examples weren't good; so much for coding in my head. You'll have to modify your views to insert the model's cid in a data-cid attribute on the li. Then you can update the correct model using your collection's .get method. I see you've found an answer of your own, as I said there are multiple approaches.
v.SurveyBuilder = v.Page.extend({
template: JST["app/templates/pages/survey-builder.hb"],
initialize: function() {
this.eventHub = EventHub;
this.questions = new c.Questions();
this.questions.on('add', this.addQuestion, this);
this.eventHub.on('questions:doneSorting', this.updateIndexes)
},
updateIndexes: function(e) {
var that = this;
this.$('li').each(function(index) {
var cid = $(this).attr('data-cid');
that.questions.get(cid).set('question_number', index);
});
}
I figured out a way to do it!!!
Make an array of child views under the parent view (in my example this.qbViews maintains an array of QuestionBuilder views) for the SurveyBuilder view
For your collection (in my case this.questions), set the remove event using on to updateIndexes. That means it will run updateIndexes every time something is removed from this.questions
In your events object in the parent view, add a sortstop event for your sortable object (in my case startstop .question-builders, which is the UL holding the questionBuilder views) to also point to updateIndexes
In updateIndexes do the following:
updateIndexes: function(){
//Go through each of our Views and set the underlying model's question_number to
//whatever the index is in the list + 1
_.each(this.qbViews, function(qbView){
var index = qbView.$el.index();
//Only actually `set`s if it changed
qbView.model.set('question_number', index + 1);
});
},
And there is my full code for SurveyBuilder view:
v.SurveyBuilder = v.Page.extend({
template: JST["app/templates/pages/survey-builder.hb"],
initialize: function() {
this.qbViews = []; //will hold all of our QuestionBuilder views
this.questions = new c.Questions(); //will hold the Questions collection
this.questions.on('add', this.addQuestion, this);
this.questions.on('remove', this.updateIndexes, this); //We need to update Question Numbers
},
bindSortable: function() {
$('.question-builders').sortable({
items: '>li',
handle: '.move-question',
placeholder: 'placeholder span11'
});
},
addQuestion: function(question) {
var view = new v.QuestionBuilder({
model: question
});
//Push it onto the Views array
this.qbViews.push(view);
$('.question-builders').append(view.render().el);
this.bindSortable();
},
updateIndexes: function(){
//Go through each of our Views and set the underlying model's question_number to
//whatever the index is in the list + 1
_.each(this.qbViews, function(qbView){
var index = qbView.$el.index();
//Only actually `set`s if it changed
qbView.model.set('question_number', index + 1);
});
},
events: {
'click .add-question': function() {
this.questions.add({});
},
//need to update question numbers when we resort
'sortstop .question-builders': 'updateIndexes'
}
});
And here is the permalink to my Views file for the full code:
https://github.com/nycitt/node-survey-builder/blob/1bee2f0b8a04006aac10d7ecdf6cb19b29de8c12/app/js/survey-builder/views.js
When I add collection to the view like this:
var View = new MyCollectionView({ collection: new MyCollection() });
everything is okey. I can use this collection in initialize method (for binding events, for example). But how can I add another one?
I can't do this way:
var View = new MyCollectionView({
collection: new MyCollection(),
secondCollection: new MySecondCollection()
});
From the fine manual:
constructor / initialize new View([options])
There are several special options that, if passed, will be attached directly to the view: model, collection, el, id, className, tagName, attributes and events.
So, if you create a view like this:
new View({collection: c})
then Backbone will automatically assign c to the view's this.collection. But if you create the view like this:
new View({collection: c, secondCollection: c2})
then inside the View's constructor:
initialize: function(options) {
// this.collection will be 'c' from above
// options.secondCollection will be 'c2'
}
So you can do this:
var View = new MyCollectionView({
collection: new MyCollection(),
secondCollection: new MySecondCollection()
});
provided that your MyCollectionView has an initialize method that knows to pull the secondCollection out of its options argument.
Open your JavaScript console and have a look at what this does:
var V = Backbone.View.extend({
initialize: function(options) {
var c1 = options.collection;
var c2 = options.secondCollection;
console.log(this.collection);
console.log(c1);
console.log(c2);
}
});
var view = new V({collection: 1, secondCollection: 2});
Demo: http://jsfiddle.net/ambiguous/XyeSD/