Question

Backbone的文档说明：

events属性也可以定义为一个返回事件哈希的函数，以便更容易以编程方式定义事件，并从父视图继承它们。

如何继承父视图事件并扩展它们？

父视图

var ParentView = Backbone.View.extend({
   events: {
      'click': 'onclick'
   }
});

子视图

var ChildView = ParentView.extend({
   events: function(){
      ????
   }
});

Answer 1

一种方法是：

var ChildView = ParentView.extend({
   events: function(){
      return _.extend({},ParentView.prototype.events,{
          'click' : 'onclickChild'
      });
   }
});

另一个是：

var ParentView = Backbone.View.extend({
   originalEvents: {
      'click': 'onclick'
   },
   //Override this event hash in
   //a child view
   additionalEvents: {
   },
   events : function() {
      return _.extend({},this.originalEvents,this.additionalEvents);
   }
});

var ChildView = ParentView.extend({
   additionalEvents: {
      'click' : ' onclickChild'
   }
});

检查事件是功能还是对象

var ChildView = ParentView.extend({
   events: function(){
      var parentEvents = ParentView.prototype.events;
      if(_.isFunction(parentEvents)){
          parentEvents = parentEvents();
      }
      return _.extend({},parentEvents,{
          'click' : 'onclickChild'
      });
   }
});

Answer 2

士兵。这个答案很好。进一步简化它你可以做以下

var ChildView = ParentView.extend({
   initialize: function(){
       _.extend(this.events, ParentView.prototype.events);
   }
});

然后以典型的方式在任一类中定义您的事件。

Answer 3

您还可以使用defaults方法来避免创建空对象{}。

var ChildView = ParentView.extend({
  events: function(){
    return _.defaults({
      'click' : 'onclickChild'
    }, ParentView.prototype.events);
  }
});

Answer 4

如果您使用CoffeeScript并将功能设置为events，则可以使用super。

class ParentView extends Backbone.View
  events: ->
    'foo' : 'doSomething'

class ChildView extends ParentView
  events: ->
    _.extend {}, super,
      'bar' : 'doOtherThing'

Answer 5

从Backbone.View创建专门的基础构造函数更容易，它可以处理层次结构中事件的继承。

BaseView = Backbone.View.extend {
    # your prototype defaults
},
{
    # redefine the 'extend' function as decorated function of Backbone.View
    extend: (protoProps, staticProps) ->
      parent = this

      # we have access to the parent constructor as 'this' so we don't need
      # to mess around with the instance context when dealing with solutions
      # where the constructor has already been created - we won't need to
      # make calls with the likes of the following:   
      #    this.constructor.__super__.events
      inheritedEvents = _.extend {}, 
                        (parent.prototype.events ?= {}),
                        (protoProps.events ?= {})

      protoProps.events = inheritedEvents
      view = Backbone.View.extend.apply parent, arguments

      return view
}

这允许我们在使用重新定义的扩展函数创建新的子类（子构造函数）时，减少（合并）层次结构中的事件哈希。

# AppView is a child constructor created by the redefined extend function
# found in BaseView.extend.
AppView = BaseView.extend {
    events: {
        'click #app-main': 'clickAppMain'
    }
}

# SectionView, in turn inherits from AppView, and will have a reduced/merged
# events hash. AppView.prototype.events = {'click #app-main': ...., 'click #section-main': ... }
SectionView = AppView.extend {
    events: {
        'click #section-main': 'clickSectionMain'
    }
}

# instantiated views still keep the prototype chain, nothing has changed
# sectionView instanceof SectionView => true 
# sectionView instanceof AppView => true
# sectionView instanceof BaseView => true
# sectionView instanceof Backbone.View => also true, redefining 'extend' does not break the prototype chain. 
sectionView = new SectionView { 
    el: ....
    model: ....
}

通过创建一个专门的视图：重新定义扩展函数的BaseView，我们可以通过从BaseView或其中一个扩展来获得想要继承其父视图的声明事件的子视图（如AppView，SectionView）。衍生物。

我们避免在子视图中以编程方式定义事件函数的需要，在大多数情况下需要明确地引用父构造函数。

Answer 6

@ soldier.moth的最后一个建议的简短版本：

var ChildView = ParentView.extend({
  events: function(){
    return _.extend({}, _.result(ParentView.prototype, 'events') || {}, {
      'click' : 'onclickChild'
    });
  }
});

Answer 7

这也有效：

class ParentView extends Backbone.View
  events: ->
    'foo' : 'doSomething'

class ChildView extends ParentView
  events: ->
    _.extend({}, _.result(_super::, 'events') || {},
      'bar' : 'doOtherThing')

使用直接super并不适用于我，要么是手动指定ParentView，要么是继承的类。

访问任何coffeescript _super

中可用的Class … extends … var

Answer 8

＆＃13;

// ModalView.js
var ModalView = Backbone.View.extend({
	events: {
		'click .close-button': 'closeButtonClicked'
	},
	closeButtonClicked: function() { /* Whatever */ }
	// Other stuff that the modal does
});

ModalView.extend = function(child) {
	var view = Backbone.View.extend.apply(this, arguments);
	view.prototype.events = _.extend({}, this.prototype.events, child.events);
	return view;
};

// MessageModalView.js
var MessageModalView = ModalView.extend({
	events: {
		'click .share': 'shareButtonClicked'
	},
	shareButtonClicked: function() { /* Whatever */ }
});

// ChatModalView.js
var ChatModalView = ModalView.extend({
	events: {
		'click .send-button': 'sendButtonClicked'
	},
	sendButtonClicked: function() { /* Whatever */ }
});

＆＃13;

http://danhough.com/blog/backbone-view-inheritance/

Answer 9

对于Backbone版本1.2.3，__super__工作正常，甚至可能被链接。 E.g：

// A_View.js
var a_view = B_View.extend({
    // ...
    events: function(){
        return _.extend({}, a_view.__super__.events.call(this), { // Function - call it
            "click .a_foo": "a_bar",
        });
    }
    // ...
});

// B_View.js
var b_view = C_View.extend({
    // ...
    events: function(){
        return _.extend({}, b_view.__super__.events, { // Object refence
            "click .b_foo": "b_bar",
        });
    }
    // ...
});

// C_View.js
var c_view = Backbone.View.extend({
    // ...
    events: {
        "click .c_foo": "c_bar",
    }
    // ...
});

...在A_View.js中 - 将导致：

events: {
    "click .a_foo": "a_bar",
    "click .b_foo": "b_bar",
    "click .c_foo": "c_bar",
}

Answer 10

我在article

中找到了一个更有趣的解决方案

使用Backbone的 super 和ECMAScript的hasOwnProperty。其进步的第二个例子就像一个魅力。这是一个代码：

var ModalView = Backbone.View.extend({
    constructor: function() {
        var prototype = this.constructor.prototype;

        this.events = {};
        this.defaultOptions = {};
        this.className = "";

        while (prototype) {
            if (prototype.hasOwnProperty("events")) {
                _.defaults(this.events, prototype.events);
            }
            if (prototype.hasOwnProperty("defaultOptions")) {
                _.defaults(this.defaultOptions, prototype.defaultOptions);
            }
            if (prototype.hasOwnProperty("className")) {
                this.className += " " + prototype.className;
            }
            prototype = prototype.constructor.__super__;
        }

        Backbone.View.apply(this, arguments);
    },
    ...
});

您也可以为 ui 和属性执行此操作。

此示例不处理函数设置的属性，但本文作者在这种情况下提供了解决方案。

Answer 11

这个CoffeeScript解决方案对我有用（并考虑到@ soldier.moth的建议）：

class ParentView extends Backbone.View
  events: ->
    'foo' : 'doSomething'

class ChildView extends ParentView
  events: ->
    _.extend({}, _.result(ParentView.prototype, 'events') || {},
      'bar' : 'doOtherThing')

Answer 12

如果您确定ParentView将事件定义为对象，并且您不需要在ChildView中动态定义事件，则可以进一步简化士兵。摆脱该功能并直接使用_.extend：

var ParentView = Backbone.View.extend({
    events: {
        'click': 'onclick'
    }
});

var ChildView = ParentView.extend({
    events: _.extend({}, ParentView.prototype.events, {
        'click' : 'onclickChild'
    })
});

Answer 13

我喜欢的模式是修改构造函数并添加一些额外的功能：

// App View
var AppView = Backbone.View.extend({

    constructor: function(){
        this.events = _.result(this, 'events', {});
        Backbone.View.apply(this, arguments);
    },

    _superEvents: function(events){
        var sooper = _.result(this.constructor.__super__, 'events', {});
        return _.extend({}, sooper, events);
    }

});

// Parent View
var ParentView = AppView.extend({

    events: {
        'click': 'onclick'
    }

});

// Child View
var ChildView = ParentView.extend({

    events: function(){
        return this._superEvents({
            'click' : 'onclickChild'
        });
    }

});

我更喜欢这种方法，因为您不必识别要更改的父-one less变量。我对attributes和defaults使用相同的逻辑。

Answer 14

哇，这里有很多答案，但我想我还会再提供一个。如果您使用BackSupport库，则会提供extend2。如果您使用extend2，则会自动为您合并events（以及defaults和类似属性）。

这是一个简单的例子：

var Parent = BackSupport.View.extend({
    events: {
        change: '_handleChange'
    }
});
var Child = parent.extend2({
    events: {
        click: '_handleClick'
    }
});
Child.prototype.events.change // exists
Child.prototype.events.click // exists

https://github.com/machineghost/BackSupport

Answer 15

完全在父类中执行此操作并在子类中支持基于函数的事件哈希，以便子项可以不依赖继承（如果子项覆盖MyView.prototype.initialize，则必须调用initialize }）：

var MyView = Backbone.View.extend({
  events: { /* ... */ },

  initialize: function(settings)
  {
    var origChildEvents = this.events;
    this.events = function() {
      var childEvents = origChildEvents;
      if(_.isFunction(childEvents))
         childEvents = childEvents.call(this);
      return _.extend({}, : MyView.prototype.events, childEvents);
    };
  }
});

骨干视图：从父级继承和扩展事件

父视图

子视图

15 个答案: