主干在初始化时看不到模型更改。正常吗？

Question

在模型初始化时设置了一些参数。View初始化的监听器必须捕获该事件。但事实并非如此。然而，它可以做到以下事件(如按钮的点击)。所以问题:

• 是正常行为吗?
• 如果是，那么目的是什么
• 如果没有，我的错误是什么?

游戏的地方在这里:http://plnkr.co/edit/ddIZrkoI1n1CE6YrvMrC?p=preview

$(function(){
  var Mod = Backbone.Model.extend({
    defaults:{
          test:null
    },
    initialize: function(){
      this.set('test', 'hello');
      console.log(this.attributes);
    }
  });
  var Vw = Backbone.View.extend({
    events : {
      'click #btn-change' : function(){
        var mod_value = $('[name="data-input"]').val();
        console.log('mod_value: '+mod_value);
        this.model.set('test', mod_value);
      }
    },
    initialize: function(){
      console.dir({
        model: this.model,
        view: this
      }); 
      this.listenTo(this.model, 'change', function(){
        console.log('%cModel changed', 'font-size:18px; color: navy');
        console.log({
          model_changed: this.model.changed,
                    keys: _.keys(this.model.changed),
                    attributes: this.model.attributes
        });
        $('#new-data').html('<h4>Model is changed</h4>'+this.model.get('test'));
      });
    }
  });
  var md = new Mod(), nv = new Vw({
    model: md,
    el:$('body')
  });
});

Answer 1

如果你需要在模型的初始化中设置事件，因为model.changed直到下一个set才会改变，并且你的处理程序不依赖于事件给出的参数，你可以在视图的init中手动调用更改事件处理程序，如Altered Plunker，或使用model.trigger('change', ...)触发更改处理程序。

$(function(){
  var Vw = Backbone.View.extend({
    events : {
      'click #btn-change' : function(){
        var mod_value = $('[name="data-input"]').val();
        console.log('mod_value: '+mod_value);
        this.model.set('test', mod_value);
      }
    },
    initialize: function(){
      console.dir({
        model: this.model,
        view: this
      }); 
      // Pull the handler out as an attr of view's
      this.listenTo(this.model, 'change', this.onModelChanged);
      // Manually call the handler to get the changes made by mode's 
      // initialization.
      this.onModelChanged();
    },
    onModelChanged: function(){
        console.log('%cModel changed', 'font-size:18px; color: navy');
        console.log({
          model_changed: this.model.changed,
                    keys: _.keys(this.model.changed),
                    attributes: this.model.attributes
        });
        $('#new-data').html('<h4>Model is changed</h4>'+this.model.get('test'));
    }
  });
  var Mod = Backbone.Model.extend({
    defaults:{
      test:null
    },
    initialize: function(){
      this.set('test', 'hello');
      console.log(this.attributes);
    }
  });
  var md = new Mod(), nv = new Vw({
    model: md,
    el:$('body')
  });
});