我有一个名为 Pannel
的视图,它只是一个带有关闭按钮的背景。 我想将该视图扩展为名为 PannelAdvanced
的视图。 如何使用backbone.js实现此操作?
目前所有示例都使用Backbone.View.Extend
,但这些示例仅扩展了Backbone.View
; 我想扩展我的PannelView
。
我有一个名为 Pannel
的视图,它只是一个带有关闭按钮的背景。 我想将该视图扩展为名为 PannelAdvanced
的视图。 如何使用backbone.js实现此操作?
目前所有示例都使用Backbone.View.Extend
,但这些示例仅扩展了Backbone.View
; 我想扩展我的PannelView
。
继承视图最简单的方法是按照评论中其他人已经建议的去做:
var Pannel = Backbone.View.extend({
});
var PannelAdvanced = Pannel.extend({
});
但是就像你在评论中所指出的那样,如果Pannel中有一个initialize方法,那么如果你还在PannelAdvanced中有一个initialize方法,就不会调用它。因此,你必须显式地调用Pannel的initialize方法:
var Pannel = Backbone.View.extend({
initialize: function(options){
console.log('Pannel initialized');
this.foo = 'bar';
}
});
var PannelAdvanced = Pannel.extend({
initialize: function(options){
Pannel.prototype.initialize.apply(this, [options])
console.log('PannelAdvanced initialized');
console.log(this.foo); // Log: bar
}
});
如果你有很多从Pannel继承的视图,那么这个方法会有点丑陋,因为你需要记得从所有这些视图中调用Pannel的initialize方法。更糟糕的是,如果现在的Pannel没有initialize方法,但是你将来决定添加它,那么你需要去找所有继承类,并确保它们调用了Pannel的initialize方法。所以这里是另一种定义Pannel的方法,这样你继承的视图就不需要调用Pannel的initialize方法:
var Pannel = function (options) {
// put all of Panel's initialization code here
console.log('Pannel initialized');
this.foo = 'bar';
Backbone.View.apply(this, [options]);
};
_.extend(Pannel.prototype, Backbone.View.prototype, {
// put all of Panel's methods here. For example:
sayHi: function () {
console.log('hello from Pannel');
}
});
Pannel.extend = Backbone.View.extend;
// other classes inherit from Panel like this:
var PannelAdvanced = Pannel.extend({
initialize: function (options) {
console.log('PannelAdvanced initialized');
console.log(this.foo);
}
});
var pannelAdvanced = new PannelAdvanced(); //Log: Pannel initialized, PannelAdvanced initialized, bar
pannelAdvanced.sayHi(); // Log: hello from Pannel
var PannelAdvanced = Pannel.extend({events:{...}})
时,字典中父类的事件键被子类的覆盖了。你可以在父类中声明一个parentEvents键,在父类构造函数中调用this.delgateEvents(this.parentEvents)
,但是由于backbone中的this line,它们会再次被子视图删除。 - AJPchildEvents
键下声明子事件,然后在父级中用 return _.extend({"click .parentClass": "parentFunction"}, this.childEvents)
声明一个 events
函数。 - AJP_super
不是最佳选择。https://github.com/jashkenas/backbone/pull/787#issuecomment-14327908 - Thiago Festa这就是我喜欢使用Coffeescript的原因之一。像继承这样的东西更加方便易用。为了附和@JohnnyO的正确答案,我可以在Coffeescript中这么写:
class Panel extends Backbone.View
initialize: ->
console.log 'Panel initialized'
@foo = 'bar'
class PanelAdvanced extends Panel
initialize: ->
super
console.log 'PanelAdvanced initialized'
console.log @foo
super
变为 Panel.prototype.initialize.apply(this, arguments);
- NicoGranellithis.options
中。 - maletor进一步附带一点:
我喜欢@JohnnyO的方法,但想确认结果视图仍然能够完成它应该做的所有事情。考虑到他的方法,我并不认为会有任何问题,但我想要更加确定。
因此,我花了一分钟时间,将Backbone.js Views test suite调整为@JohnnyO建议的多重继承技术。
您可以在http://jsfiddle.net/dimadima/nPWuG/上运行结果。所有测试都通过了。
我的基本视图和扩展视图:
var RegularView = function (options) {
// All of this code is common to both a `RegularView` and `SuperView`
// being constructed.
this.color = options && (options.color || 'Green');
// If execution arrives here from the construction of
// a `SuperView`, `Backbone.View` will call `initialize`
// that belongs to `SuperView`. This happens because here
// `this` is `SuperView`, and `Backbone.View`, applied with
// the current `this` calls `this.initialize.apply(this, arguments)`
Backbone.View.apply(this, arguments)
};
RegularView.extend = Backbone.View.extend;
_.extend(RegularView.prototype, Backbone.View.prototype, {
// Called if a `RegularView` is constructed`,
// Not called if a `SuperView` is constructed.
initialize: function () {
console.log('RegularView initialized.');
},
say_hi: function() {
console.log('Regular hi!');
}
});
var SuperView = RegularView.extend({
// Called if a `SuperView` is constructed`,
// Not called if a `RegularView` is constructed.
initialize: function(options) {
console.log('SuperView initialized.')
},
say_hi: function() {
console.log('Super hi!');
}
})
Backbone.View
替换为RegularView
。之后测试使用RegularView
和RegularView.extend()
的结果来确保两者都能正常运行。
Panel.extend({ ... })
- nrabinowitz