I have two backbone view and I want to use third view which will be extended from both
view1 = Backbone.View.extend({});
view2 = Backbone.View.extend({});
view3 (extended from view1 and view2)
Can anyone help me out
I've not tried it but this should work, taken from: https://gist.github.com/alassek/1227770
(function () {
function extendEach () {
var args = Array.prototype.slice.call(arguments),
child = this;
_.each(args, function (proto) {
child = child.extend(proto);
});
return child;
}
Backbone.Model.extendEach =
Backbone.Collection.extendEach =
Backbone.Router.extendEach =
Backbone.View.extendEach = extendEach;
})();
ClassC = Backbone.Model.extendEach(ClassA, ClassB, [properties])
I've found this solution much easier, in your case would be:
_.extend(view3.prototype, view1.prototype, view2.prototype);
Example for Backbone:
http://jsfiddle.net/M5J8Q/1809/
Example for Marionette:
http://jsfiddle.net/M5J8Q/1810/
Also you can do this:
view3.extend(view1.prototype);
view3.extend(view2.prototype);
Fiddle: http://jsfiddle.net/M5J8Q/1811/
Greetings!
Related
I am using same el for more than 1 view like below. I'm not facing any problem till now. Is this good approach or should i do any changes?
<div id="app">
<div id="app-header"></div>
<div id="app-container"></div>
<div id="app-footer">
</div>
App View:
{
el: "#app",
v1: new View1(),
v2: new View2(),
render: function () {
if (cond1) {
this.v1.render();
} else if (cond2) {
this.v2.render();
}}
}
View 1:
{
el: "#app-container",
render: function (){
this.$el.html(template);
}
}
View 2:
{
el: "#app-container",
render: function (){
this.$el.html(template);
}
}
By reading your question, I do not really see what advantages you could possibly have using this approach rather than having the different div elements being the root el for your views 1, 2, 3 and using
this.$el.html(template)
in the render method.
Your approach could work for a small application, but I think it will become really hard to maintain as the application grows.
EDIT
I still do not really get your point, you could only initialize everything only once in both cases.
Here is a working Fiddle.
By the way I am changing the content by listening to the click event but this is to simplify the example. It should be done by the router.
I do use a mixin to handle such situation, I call it stated view. For a view with all other options I will send a parameter called 'state', render will in-turn call renderState first time and there after every time I set a 'state' renderState will update the view state. Here is my mixin code looks like.
var setupStateEvents = function (context) {
var stateConfigs = context.getOption('states');
if (!stateConfigs) {
return;
}
var state;
var statedView;
var cleanUpState = function () {
if (statedView) {
statedView.remove();
}
};
var renderState = function (StateView) {
statedView = util.createView({
View: StateView,
model: context.model,
parentEl: context.$('.state-view'),
parentView:context
});
};
context.setState = function (toState) {
if (typeof toState === 'string') {
if (state === toState) {
return;
}
state = toState;
var StateView = stateConfigs[toState];
if (StateView) {
cleanUpState();
renderState(StateView);
} else {
throw new Error('Invalid State');
}
} else {
throw new Error('state should be a string');
}
};
context.getState = function () {
return state;
};
context.removeReferences(function(){
stateConfigs = null;
state=null;
statedView=null;
context=null;
})
};
full code can be seen here
https://github.com/ravihamsa/baseapp/blob/master/js/base/view.js
hope this helps
Backbone Rule:
When you create an instance of a view, it'll bind all events to el if
it was assigned, else view creates and assigns an empty div as el for that view and bind
all events to that view.
In my case, if i assign #app-container to view 1 and view 2 as el and when i initialize both views like below in App View, all events bind to the same container (i.e #app-container)
this.v1 = new App.View1();
this.v2 = new App.View2();
Will it lead to any memory leaks / Zombies?
No way. No way. Because ultimately you are having only one instance for each view. So this won't cause any memory leaks.
Where does it become problematic?
When your app grows, it is very common to use same id for a tag in both views. For example, you may have button with an id btn-save in both view's template. So when you bind btn-save in both views and when you click button in any one the view, it will trigger both views save method.
See this jsFiddle. This'll explain this case.
Can i use same el for both view?
It is up to you. If you avoid binding events based on same id or class name in both views, you won't have any problem. But you can avoid using same id but it's so complex to avoid same class names in both views.
So for me, it looks #Daniel Perez answer is more promising. So i'm going to use his approach.
Basically I've a panel called DummyPanel, Now on dummypanel initialize event I've called a controller function like as follows:
var me = component;
var fieldCollection =
{
"Order" : 'ordNumber',
"Ref": 'refNumber'
};
me.fireEvent('myControllerFunction','Param1', fieldCollection, 'Param3');
Now I want to get fieldCollection JSON object value within function myControllerFunction, to get value from fieldCollection I'm using following code:
myControllerFunction(param1, collection, param3)
{
Ext.Msg.alert(collection.Order);
}
But it does not return anything. So please let me know how to resolve this problem!!
Any comment will appreciated!!
I'm not quite sure what it means "But it does not return anything", but I'll try.
So, your "DummyPanel" view have a alias or itemId property. In yor controller (in init() function), you need "keep track" of your view. For example:
In your view:
me.fireEvent('myEventName','Param1', fieldCollection, 'Param3');
In your controller:
init:function(){
var me = this;
this.control({
'panel[itemId=your-view-itemId]': { // call your function after event
myEventName: me.myControllerFunction
}
});
...
},
...
myControllerFunction: function(...) {
...
}
Should it not be
Ext.Msg.alert(collection["Order"])?
Or if you want to keep Ext.Msg.alert the way it is fieldCollection should be defined this way
var fieldCollection =
{
Order : 'ordNumber',
Ref : 'refNumber'
};
I am trying to nest a Collection View into a Model View.
In order to do so, I used Backbone's Marionnette Composite View and followed that tutorial
At the end he initializes the nested collection view like this:
MyApp.addInitializer(function(options){
var heroes = new Heroes(options.heroes);
// each hero's villains must be a backbone collection
// we initialize them here
heroes.each(function(hero){
var villains = hero.get('villains');
var villainCollection = new Villains(villains);
hero.set('villains', villainCollection);
});
// edited for brevity
});
How would you go doing the same without using the addInitalizer from Marionette?
In my project I am fectching data from the server. And when I try doing something like:
App.candidatures = new App.Collections.Candidatures;
App.candidatures.fetch({reset: true}).done(function() {
App.candidatures.each(function(candidature) {
var contacts = candidature.get('contacts');
var contactCollection = new App.Collections.Contacts(contacts);
candidature.set('contacts', contactCollection);
});
new App.Views.App({collection: App.candidatures});
});
I get an "indefined options" coming from the collection:
App.Collections.Contacts = Backbone.Collection.extend({
model: App.Models.Contact,
initialize:function(models, options) {
this.candidature = options.candidature;
},
url:function() {
return this.candidature.url() + "/contacts";
}
)};
That's because when you're creating the contactCollection, you're not providing a candidatures collections in an options object. You do need to modify your contact collection initialization code to something like:
initialize:function(models, options) {
this.candidature = options && options.candidature;
}
That way the candidature attribute will be set to the provided value (and if not provided, it will be undefined).
Then, you still need to provide the info when you're instanciating the collection:
App.candidatures.each(function(candidature) {
var contacts = candidature.get('contacts');
var contactCollection = new App.Collections.Contacts(contacts, {
candidature: candidature
});
candidature.set('contacts', contactCollection);
});
P.S.: I hope you found my blog post useful!
Given a page that uses Backbone.js to have a Collection tied to a View (RowsView, creates a <ul>) which creates sub Views (RowView, creates <li>) for each Model in the collection, I've got an issue setting up inline editing for those models in the collection.
I created an edit() method on the RowView view that replaces the li contents with a text box, and if the user presses tab while in that text box, I'd like to trigger the edit() method of the next View in the list.
I can get the model of the next model in the collection:
// within a RowView 'keydown' event handler
var myIndex = this.model.collection.indexOf(this.model);
var nextModel = this.model.collection.at(myIndex+1);
But the question is, how to find the View that is attached to that Model. The parent RowsView View doesn't keep a reference to all the children Views; it's render() method is just:
this.$el.html(''); // Clear
this.model.each(function (model) {
this.$el.append(new RowView({ model:model} ).render().el);
}, this);
Do I need to rewrite it to keep a separate array of pointers to all the RowViews it has under it? Or is there a clever way to find the View that's got a known Model attached to it?
Here's a jsFiddle of the whole problem: http://jsfiddle.net/midnightlightning/G4NeJ/
It is not elegant to store a reference to the View in your model, however you could link a View with a Model with events, do this:
// within a RowView 'keydown' event handler
var myIndex = this.model.collection.indexOf(this.model);
var nextModel = this.model.collection.at(myIndex+1);
nextModel.trigger('prepareEdit');
In RowView listen to the event prepareEdit and in that listener call edit(), something like this:
this.model.on('prepareEdit', this.edit);
I'd say that your RowsView should keep track of its component RowViews. The individual RowViews really are parts of the RowsView and it makes sense that a view should keep track of its parts.
So, your RowsView would have a render method sort of like this:
render: function() {
this.child_views = this.collection.map(function(m) {
var v = new RowView({ model: m });
this.$el.append(v.render().el);
return v;
}, this);
return this;
}
Then you just need a way to convert a Tab to an index in this.child_views.
One way is to use events, Backbone views have Backbone.Events mixed in so views can trigger events on themselves and other things can listen to those events. In your RowView you could have this:
events: {
'keydown input': 'tab_next'
},
tab_next: function(e) {
if(e.keyCode != 9)
return true;
this.trigger('tab-next', this);
return false;
}
and your RowsView would v.on('tab-next', this.edit_next); in the this.collection.map and you could have an edit_next sort like this:
edit_next: function(v) {
var i = this.collection.indexOf(v.model) + 1;
if(i >= this.collection.length)
i = 0;
this.child_views[i].enter_edit_mode(); // This method enables the <input>
}
Demo: http://jsfiddle.net/ambiguous/WeCRW/
A variant on this would be to add a reference to the RowsView to the RowViews and then tab_next could directly call this.parent_view.edit_next().
Another option is to put the keydown handler inside RowsView. This adds a bit of coupling between the RowView and RowsView but that's probably not a big problem in this case but it is a bit uglier than the event solution:
var RowsView = Backbone.View.extend({
//...
events: {
'keydown input': 'tab_next'
},
render: function() {
this.child_views = this.collection.map(function(m, i) {
var v = new RowView({ model: m });
this.$el.append(v.render().el);
v.$el.data('model-index', i); // You could look at the siblings instead...
return v;
}, this);
return this;
},
tab_next: function(e) {
if(e.keyCode != 9)
return true;
var i = $(e.target).closest('li').data('model-index') + 1;
if(i >= this.collection.length)
i = 0;
this.child_views[i].enter_edit_mode();
return false;
}
});
Demo: http://jsfiddle.net/ambiguous/ZnxZv/
I have several views that have common code I'd like to abstract into a custom Backbone.View class. Is there any best practices for doing this?
is a good pattern to do something like this? :
// Base Grid view
var GridView = Backbone.View.extend({
initialize : function(){
//common view init code ..
//do the plug in overrides
if (options.addHandler)
this.addHandler = options.addHandler;
if (options.events)
//?? extend default events or override?
this.events = $.extend(this.events, options.events);
},
addHandler : function() {
//defaulthandler this code can be overridden
});
});
// in another object create some views from the GridView base
....
var overrides = { events:"xxx yyy", el: ulElement addHandler: myAddFunction }
var UserList = GridView.extend(overrides)
var userList = new UserList(users, options);
....
var coursesOverrides : {addHandler: ...}
var coursesOptions: {el: courseElement, ...}
var CourseList = GridView.extend(coursesOverrides)
var courseList= new CourseList (courses, coursesOptions)
// along the same lines maybe there's an abstraction for toolbar views
var ClassToolbarView = ToolbarBase.extend(toolOverrides)
var classtoolbar = new ClassToolbarView(actions, toolbaropts)
Any pointers to good examples of extending a View for refactoring common view code is appreciated.
First, I don't see the options being passed in your initializer(), so that's a bug.
Secondly, the .extend() method is inherited:
var GridView = Backbone.View.extend({ ... })
var GridViewWithNewFunctionsAndEvents = GridView.extend({ ... })
And you can replace or extend GridView's functionality, and call new GridViewWithNewFunctionsAndEvents() and get the extra functionality in a new object you need, just like you extend the Backbone stock View class.
If you need to extend the initializer, you can do this to call the initializer on the superclass:
var GridViewWithNewFunctionsAndEvents = GridView.extend({
initializer: function(options) {
GridView.prototype.initializer.call(this, options);
/* Your stuff goes here */
}
});