I'm creating a slideshow using Backbone.js. My slideshow view is finished, each slide is a model and all the models are inside a collection. Now I want to apply a little hashbang magic to my slideshow :-)
This is my code structure
application.js
models/slideshow/slide.js
collections/slideshow/slides.js
views/slideshow.js
In application.js I create my router:
var App = {};
App.Modules = {
Views: {},
Models: {},
Collections: {}
};
App.slideshow = undefined; // Use this to maintain state between calls.
App.router = (function() {
var Router = Backbone.Router.extend({
routes: {
'slideshow/:id/:page': 'slideshow'
},
slideshow: function(id, page) {
// Whenever this route handler triggers, I want to either:
// 1) Instantiate the slideshow, or:
// 2) Change the page on an already instantiated slideshow
if (App.slideshow && App.slideshow.options.id === id) {
App.slideshow.goToPage(page);
} else {
App.slideshow = new App.Modules.Views.Slideshow({
id: id,
page: page
});
}
}
});
return new Router;
})();
// Using jQuery's document ready handler.
$(function() {
Backbone.history.start({
root: '/'
});
});
This works as I expect. My slideshow works as an overlay so no matter what page it's instantiated on, it will just show itself on top of the existing document.
My first question is how do I close the slideshow (App.slideshow.close()); when the user hits the browser back button or navigates to another hashbang, which doesn't follow the /slideshow/:id/:page syntax?
My last question has to do with the 'navigate' method in Routers. In my slideshow view, I make sure to update the hash fragment whenever the page changes. This is what I do in my view:
pageChange: function(page) {
App.router.navigate('slideshow/' + this.options.id + '/' + page, false);
}
This makes sure the fragment gets updated so that the user at any point can copy the URL and it will open on the same page. The problem is that my 'slideshow' method in my instantiated router triggers even though I pass false in the second 'navigate' parameter (triggerRoute). Why is this?
So, I think I've figured it out. Please let me know if there are cleaner ways to do this.
After reading http://msdn.microsoft.com/en-us/scriptjunkie/hh377172 I saw you can do this in Backbone.js:
var router = Backbone.Router.extend({
routes: {
'*other': 'defaultRoute'
},
defaultRoute: function() {
if (App.slideshow) App.slideshow.close();
}
};
This makes sure everything that doesn't match /slideshow/:id/:page will close the slideshow if it's been instantiated.
With regard to 'navigate' apparently it's because I did App.vent = _.extend({}, Backbone.events); Apparently, I have to do:
App.vent = {};
_.extend(App.vent, Backbone.events);
Related
I have the shell view that contains the navbar and the map. To this view is rendered other views that use the map previous rendered. When I'll go to the view perfil the map is removed, but the navbar is maintained, so far so good. My problem is when turn back to the home, the map doesn't appear only appears the div that contains the map. Bellow show the example:
View Shell and view Home:
go to view Perfil:
turn back to home:
heres my code:
app.js
var ev = new Application();
ev.Router = Backbone.Router.extend({
routes: {
"": "home",
"evento/:id" : "evento",
"criarevento" : "criarevento",
"perfil" : "perfil"
},
home: function(){
setTimeout(function(){
$('#rightcolumn').html(new ev.views.Home(ev.shell.map).el);
}, 0);
},
... // other views
perfil: function(){
setTimeout(function(){
$('#home').html(new ev.views.Perfil(ev.shell.template).el);
}, 0);
}
});
$(document).on('ready', function() {
ev.user = new ev.models.Person(); // Holds the authenticated Facebook user
// Load HTML templates for the app
ev.templateLoader.load(['shell', 'home', 'search_keyword', 'evento', 'login', 'quemvai', 'criar_evento', 'home_criar_evento', 'perfil'], function () {
ev.shell = new ev.views.Shell({el: "#shell", model: ev.user});
ev.router = new ev.Router();
Backbone.history.start();
});
});
perfil.js
ev.views.Perfil = Backbone.View.extend({
initialize: function(temp, model){
var that = this;
that.template = _.template(ev.templateLoader.get('perfil'));
that.template2 = temp;
//console.log(this.view);
ev.router.on("route", function(route, params) {
that.$el.html(that.template2());
});
that.render();
},
render: function(map){
this.$el.html(this.template());
return this;
}
});
So far I created an event that when route changes, the shell template that I step to the view perfil is called. But it's not working. What I'm doing wrong?
EDITS:
I change my constructor in view perfil, so that when route changes only fire once and call the render function of ev.shell
ev.views.Perfil = Backbone.View.extend({
initialize: function(){
var that = this;
that.template = _.template(ev.templateLoader.get('perfil'));
ev.router.once("route", function(route, params) {
ev.shell.render();
});
that.render();
},
render: function(map){
this.$el.html(this.template());
return this;
}
});
It looks like you have a document ready even that loads the shell including the map. When you go to the profile page you replace the contents of the #home element. Then when you go back to home you replace the contents of the #rightcolumn element. You never re-render the map.
I think you need to put the map rendering code into the home function of the router as well.
As a side note I noticed you are using setTimeout function. If you are using this so that something renders because it's waiting on something else to load then you should probably get rid of it and listen to an event.
OK, I've done some reading on this and I'm pretty sure I know what the problem relates to I Just don't know the best way to fix it. I've got the standard backbone router that sets me up with an item details view, then when I click on a button called "start" it creates a new view which takes me to a sort of a game that people can play with some buttons on the bottom that have "click" events attached. This second view is not called through the router but directly from the first view.
The problem is the second time someones goes back to the homescreen and does it again, this time there are two events attached to each button. The third time there are three events. Obviously the original views are still listening to these buttons. I've read about this and calling the Remove() method but is this what I need to do? If so where do I call remove? Relevant Code below:
1ST VIEW
window.GameDrillView = Backbone.View.extend({
initialize: function () {
this.render();
},
render: function () {
$(this.el).html(this.template(this.model.toJSON()));
return this;
},
events: {
"click .start" : "startGameDrill",
},
startGameDrill: function () {
var start = $('#start').val();.
var stop = $('#stop').val();.
var StartView = new GameDrillStartView({model: this.model, el: $('#content')[0], start: start, stop:stop});
}
});
START VIEW
window.GameDrillStartView = Backbone.View.extend({
// declare variables
initialize: function () {
this.render();
},
events: {
"click .nextstage" : "nextstage", // 2ND TIME THROUGH GETS CALLED TWICE
},
nextstage: function () {
// Do some stuff //
this.render(); //Re-render
},
render: function () {
// Do some variables stuff
this.$el.html(this.template(jQuery.extend(this.model.toJSON(), extended_options)));..
return this;
}
});
When changing view you need to call undelegateEvents() method from the Backbone.View. It disable listening all the elements events mentioned in events { } block. Also if you need to destroy old view you can call remove() method of the view which will call undelegateEvents() internally.
update (example from official site)
var Workspace = Backbone.Router.extend({
routes: {
"help": "help", // #help
"search/:query": "search", // #search/kiwis
"search/:query/p:page": "search" // #search/kiwis/p7
},
help: function() {
if (this.currentView)
this.currentView.undelegateEvents();
this.currentView = new HelpView();
},
search: function(query, page) {
if (this.currentView)
this.currentView.undelegateEvents();
this.currentView = new SearchView();
}
});
An option is to create only one instance of the view:
if(_.isUndefined(this.StartView))
this.StartView = new GameDrillStartView({model: this.model, el: $('#content')[0], start: start, stop:stop});
else
this.StartView.render();
In the render method of GameDrillStartView add the empty method
this.$el.html(this.template(jQuery.extend(this.model.toJSON(), extended_options)))
In this way you won't add more event listeners but you'll update the page everytime the user presses the button.
You can manage the life cycle of StartView in GameDrillView since it seems like a better place to do so.
Got same trouble. Messy solution:
var current_view = false;
var prev_view = false;
var AppRouter = Backbone.Router.extend({
routes: {
"events/:id": "viewEvent",
}
});
var app_router = new AppRouter;
app_router.on('route:viewEvent', function (event_id) {
var _event = new Event({id:event_id});
current_view = new EventView({
model: _event,
});
});
//Will be called after route:viewEvent
app_router.on('route', function () {
if(prev_view) {
prev_view.undelegateEvents();
}
prev_view = current_view;
});
Not sure, how to make it without having current_view and prev_view out of router scope.
I have this strange issue where a view doesn't show up when I go to the page. However, if I refresh the page, it'll appear.
In my router, I tried to render 2 views like so:
tags: function(tags) {
self = this;
self.multipleTags = tags.split('/');
self.tagsArray = $.grep(self.multipleTags, function(item,index) {
return (item != '');
});
var browseHeader = new BrowseHeader;
var content = new tagsView({query:self.tagsArray});
},
I'm having trouble with my BrowseHeader though but the tagsView works fine. I did try removing my tagsView to see if maybe they were conflicting. However, even with a single view rendering, the header still wouldn't show up until I refresh the page.
Here is what I'm doing in my BrowseHeader view:
var browseHeader = Backbone.View.extend({
initialize: function() {
this.render();
},
template: function() {
dust.render('dust/browseHeader','', function(error, output) {
$('#wrapper').append(output);
});
},
render: function() {
this.template();
},
el: '#wrapper',
events: {
'click .academy_filter' : "click_filter"
},
click_filter: function(event) {
target = event.target;
$('.academy_filter').removeClass('active');
$(target).addClass('active');
EventBus.trigger('header:click_filter', target);
}
});
When I console.log the output, it does display the html for the output despite it not being shown on the page. So I know my dust template is working. When I simplify my BrowseHeader render function to just $('#wrapper').append("this"); I still experience the same issue.
Any ideas?
Update: Apparently it has something to do with browser and pushState because when I changed my router to the following, it worked fine.
Backbone.history.start({pushState: true});
As far as I can tell, there's nothing wrong with your view. This is most likely a timing issue. Your view is probably being initialized (and therefore rendered) before #wrapper exists in the DOM. My guess is that if you try the following, the output will be 0:
dust.render('dust/browseHeader','', function(error, output) {
console.log($('#wrapper').length);
$('#wrapper').append(output);
});
Make sure the view is being created after the DOM has finished loading, like so:
$(document).ready(function() {
var header = new browseHeader();
});
We have a single Backbone view comprised of a sidebar and several sub-views. For simplicity, we've decided to have the sidebar and sub-views governed by a single render function. However, the click .edit event seems to be firing multiple times after clicking on one of the sidebar items. For example, if I start out on "general" and click .edit, then hello fires once. If I then click .profile on the sidebar and click .edit again, hello fires twice. Any ideas?
View
events: {
"click .general": "general",
"click .profile": "profile",
"click .edit": "hello",
},
general: function() {
app.router.navigate("/account/general", {trigger: true});
},
profile: function() {
app.router.navigate("/account/profile", {trigger: true});
},
render: function(section) {
$(this.el).html(getHTML("#account-template", {}));
this.$("#sidebar").html(getHTML("#account-sidebar-template", {}));
this.$("#sidebar div").removeClass("active");
switch (this.options.section) {
case "profile":
this.$("#sidebar .profile").addClass("active");
this.$("#content").html(getHTML("#account-profile-template"));
break;
default:
this.$("#sidebar .general").addClass("active");
this.$("#content").html(getHTML("#account-general-template"));
}
},
hello: function() {
console.log("Hello world.");
},
Router
account: function(section) {
if (section) {
var section = section.toLowerCase();
}
app.view = new AccountView({model: app.user, section: section});
},
Solution
My solution was to change the router to this:
account: function(section) {
if (section) {
var section = section.toLowerCase();
}
if (app.view) {
app.view.undelegateEvents();
}
app.view = new AccountView({model: app.user, section: section});
},
This works for now, but will this create a memory leak?
I had exactly the same problem when I first started using backbone. Like Peter says, the problem is that you have more than one instance of the View being created and listening for the event. To solve this, I created this solution in my last backbone project:
/* Router view functions */
showContact:function () {
require([
'views/contact'
], $.proxy(function (ContactView) {
this.setCurrentView(ContactView).render();
}, this));
},
showBlog:function () {
require([
'views/blog'
], $.proxy(function (BlogView) {
this.setCurrentView(BlogView).render();
}, this));
},
/* Utility functions */
setCurrentView:function (view) {
if (view != this._currentView) {
if (this._currentView != null && this._currentView.remove != null) {
this._currentView.remove();
}
this._currentView = new view();
}
return this._currentView;
}
As you can see, it's always removing the last view and creating a new one, which then renders. I also add a require statement in the router because I don't want to have to load all views in the router until they are actually needed. Good luck.
Sounds like you are attaching multiple view instances to the same DOM element and they are all responding to the events. Are you making a new view each time you navigate without removing the previous view?
I have a dynamic view, that renders different templates inside the same element (about 12), based on router params. Now, the container in which the view renders, is defined inside the view.render() like so "el: '#some-container'". Naturally, i have to remove the view if it exists, before creating a new or the same one, to prevent zombies and s#!t. Just as a reminder, calling view.remove(), actually removes '#some-container' from the DOM, meaning the view has no place to render in, except for the first time. Now, there are dozens of methods to prevent this from happening. Just thought i should share in case anyone needs to save a few hours of research.
In my web application, I have a user list in a table on the left, and a user detail pane on the right. When the admin clicks a user in the table, its details should be displayed on the right.
I have a UserListView and UserRowView on the left, and a UserDetailView on the right. Things kind of work, but I have a weird behavior. If I click some users on the left, then click delete on one of them, I get successive javascript confirm boxes for all users that have been displayed.
It looks like event bindings of all previously displayed views have not been removed, which seems to be normal. I should not do a new UserDetailView every time on UserRowView? Should I maintain a view and change its reference model? Should I keep track of the current view and remove it before creating a new one? I'm kind of lost and any idea will be welcome. Thank you !
Here is the code of the left view (row display, click event, right view creation)
window.UserRowView = Backbone.View.extend({
tagName : "tr",
events : {
"click" : "click",
},
render : function() {
$(this.el).html(ich.bbViewUserTr(this.model.toJSON()));
return this;
},
click : function() {
var view = new UserDetailView({model:this.model})
view.render()
}
})
And the code for right view (delete button)
window.UserDetailView = Backbone.View.extend({
el : $("#bbBoxUserDetail"),
events : {
"click .delete" : "deleteUser"
},
initialize : function() {
this.model.bind('destroy', function(){this.el.hide()}, this);
},
render : function() {
this.el.html(ich.bbViewUserDetail(this.model.toJSON()));
this.el.show();
},
deleteUser : function() {
if (confirm("Really delete user " + this.model.get("login") + "?"))
this.model.destroy();
return false;
}
})
I always destroy and create views because as my single page app gets bigger and bigger, keeping unused live views in memory just so that I can re-use them would become difficult to maintain.
Here's a simplified version of a technique that I use to clean-up my Views to avoid memory leaks.
I first create a BaseView that all of my views inherit from. The basic idea is that my View will keep a reference to all of the events to which it's subscribed to, so that when it's time to dispose the View, all of those bindings will automatically be unbound. Here's an example implementation of my BaseView:
var BaseView = function (options) {
this.bindings = [];
Backbone.View.apply(this, [options]);
};
_.extend(BaseView.prototype, Backbone.View.prototype, {
bindTo: function (model, ev, callback) {
model.bind(ev, callback, this);
this.bindings.push({ model: model, ev: ev, callback: callback });
},
unbindFromAll: function () {
_.each(this.bindings, function (binding) {
binding.model.unbind(binding.ev, binding.callback);
});
this.bindings = [];
},
dispose: function () {
this.unbindFromAll(); // Will unbind all events this view has bound to
this.unbind(); // This will unbind all listeners to events from
// this view. This is probably not necessary
// because this view will be garbage collected.
this.remove(); // Uses the default Backbone.View.remove() method which
// removes this.el from the DOM and removes DOM events.
}
});
BaseView.extend = Backbone.View.extend;
Whenever a View needs to bind to an event on a model or collection, I would use the bindTo method. For example:
var SampleView = BaseView.extend({
initialize: function(){
this.bindTo(this.model, 'change', this.render);
this.bindTo(this.collection, 'reset', this.doSomething);
}
});
Whenever I remove a view, I just call the dispose method which will clean everything up automatically:
var sampleView = new SampleView({model: some_model, collection: some_collection});
sampleView.dispose();
I shared this technique with the folks who are writing the "Backbone.js on Rails" ebook and I believe this is the technique that they've adopted for the book.
Update: 2014-03-24
As of Backone 0.9.9, listenTo and stopListening were added to Events using the same bindTo and unbindFromAll techniques shown above. Also, View.remove calls stopListening automatically, so binding and unbinding is as easy as this now:
var SampleView = BaseView.extend({
initialize: function(){
this.listenTo(this.model, 'change', this.render);
}
});
var sampleView = new SampleView({model: some_model});
sampleView.remove();
I blogged about this recently, and showed several things that I do in my apps to handle these scenarios:
http://lostechies.com/derickbailey/2011/09/15/zombies-run-managing-page-transitions-in-backbone-apps/
This is a common condition. If you create a new view every time, all old views will still be bound to all of the events. One thing you can do is create a function on your view called detatch:
detatch: function() {
$(this.el).unbind();
this.model.unbind();
Then, before you create the new view, make sure to call detatch on the old view.
Of course, as you mentioned, you can always create one "detail" view and never change it. You can bind to the "change" event on the model (from the view) to re-render yourself. Add this to your initializer:
this.model.bind('change', this.render)
Doing that will cause the details pane to re-render EVERY time a change is made to the model. You can get finer granularity by watching for a single property: "change:propName".
Of course, doing this requires a common model that the item View has reference to as well as the higher level list view and the details view.
Hope this helps!
To fix events binding multiple times,
$("#my_app_container").unbind()
//Instantiate your views here
Using the above line before instantiating the new Views from route, solved the issue I had with zombie views.
I think most people start with Backbone will create the view as in your code:
var view = new UserDetailView({model:this.model});
This code creates zombie view, because we might constantly create new view without cleanup existing view. However it's not convenient to call view.dispose() for all Backbone Views in your app (especially if we create views in for loop)
I think the best timing to put cleanup code is before creating new view. My solution is to create a helper to do this cleanup:
window.VM = window.VM || {};
VM.views = VM.views || {};
VM.createView = function(name, callback) {
if (typeof VM.views[name] !== 'undefined') {
// Cleanup view
// Remove all of the view's delegated events
VM.views[name].undelegateEvents();
// Remove view from the DOM
VM.views[name].remove();
// Removes all callbacks on view
VM.views[name].off();
if (typeof VM.views[name].close === 'function') {
VM.views[name].close();
}
}
VM.views[name] = callback();
return VM.views[name];
}
VM.reuseView = function(name, callback) {
if (typeof VM.views[name] !== 'undefined') {
return VM.views[name];
}
VM.views[name] = callback();
return VM.views[name];
}
Using VM to create your view will help cleanup any existing view without having to call view.dispose(). You can do a small modification to your code from
var view = new UserDetailView({model:this.model});
to
var view = VM.createView("unique_view_name", function() {
return new UserDetailView({model:this.model});
});
So it is up to you if you want to reuse view instead of constantly creating it, as long as the view is clean, you don't need to worry. Just change createView to reuseView:
var view = VM.reuseView("unique_view_name", function() {
return new UserDetailView({model:this.model});
});
Detailed code and attribution is posted at https://github.com/thomasdao/Backbone-View-Manager
One alternative is to bind, as opposed to creating a series of new views and then unbinding those views. You'd accomplish this doing something like:
window.User = Backbone.Model.extend({
});
window.MyViewModel = Backbone.Model.extend({
});
window.myView = Backbone.View.extend({
initialize: function(){
this.model.on('change', this.alert, this);
},
alert: function(){
alert("changed");
}
});
You'd set the model of myView to myViewModel, which would be set to a User model. This way, if you set myViewModel to another user (i.e., changing its attributes) then it could trigger a render function in the view with the new attributes.
One problem is that this breaks the link to the original model. You could get around this by either using a collection object, or by setting the user model as an attribute of the viewmodel. Then, this would be accessible in the view as myview.model.get("model").
Use this method for clearing the child views and current views from memory.
//FIRST EXTEND THE BACKBONE VIEW....
//Extending the backbone view...
Backbone.View.prototype.destroy_view = function()
{
//for doing something before closing.....
if (this.beforeClose) {
this.beforeClose();
}
//For destroying the related child views...
if (this.destroyChild)
{
this.destroyChild();
}
this.undelegateEvents();
$(this.el).removeData().unbind();
//Remove view from DOM
this.remove();
Backbone.View.prototype.remove.call(this);
}
//Function for destroying the child views...
Backbone.View.prototype.destroyChild = function(){
console.info("Closing the child views...");
//Remember to push the child views of a parent view using this.childViews
if(this.childViews){
var len = this.childViews.length;
for(var i=0; i<len; i++){
this.childViews[i].destroy_view();
}
}//End of if statement
} //End of destroyChild function
//Now extending the Router ..
var Test_Routers = Backbone.Router.extend({
//Always call this function before calling a route call function...
closePreviousViews: function() {
console.log("Closing the pervious in memory views...");
if (this.currentView)
this.currentView.destroy_view();
},
routes:{
"test" : "testRoute"
},
testRoute: function(){
//Always call this method before calling the route..
this.closePreviousViews();
.....
}
//Now calling the views...
$(document).ready(function(e) {
var Router = new Test_Routers();
Backbone.history.start({root: "/"});
});
//Now showing how to push child views in parent views and setting of current views...
var Test_View = Backbone.View.extend({
initialize:function(){
//Now setting the current view..
Router.currentView = this;
//If your views contains child views then first initialize...
this.childViews = [];
//Now push any child views you create in this parent view.
//It will automatically get deleted
//this.childViews.push(childView);
}
});