Question

在我的测试中，我从主html文件中导入了3个元素：

    <html><head><title>my-app</title>
    <script src="bower_components/webcomponentsjs/webcomponents.min.js"></script>
    <link rel="import" href="elements/app-globals.html">
    <link rel="import" href="/Polymer/my-app/elements/my-categories.html">
    <link rel="import" href="/Polymer/my-app/elements/my-items.html">
  </head>
  <body>
    <my-categories></my-categories>
    <my-items></my-items>
  </body>
</html>

使用'app-globals.html'：

    <link rel="import" href="../bower_components/polymer/polymer.html">
<polymer-element name="app-globals" attributes="data selectedCategoryId selectedItemId">
    <script>
    (function() {
    var values = {};
    Polymer('app-globals', {
        ready: function() {
            console.log("app-globals -> ready");
            this.values = values;
            console.dir(this.values);
        },
    });
    })();
    </script>
</polymer-element>

'我的-categories.html'：

<link rel="import" href="../bower_components/polymer/polymer.html">
<link rel="import" href="/Polymer/my-app/elements/app-globals.html">

<polymer-element name="my-categories">
  <template>
    <app-globals id="globals"></app-globals>
    <div>selectedCategoryId = {{$.globals.values.selectedCategoryId}}</div>
    <ul>
      <template repeat="{{category in categories}}">
        <li class="li-category" data-_id="{{category._id}}" on-tap="{{selectCategory}}">{{category.name}}</li>
      </template>
    </ul>
  </template>
  <script>
  Polymer('my-categories', {
    values: {},
    ready: function() {
      var HOST = 'xxx.yyy.zzz.www';
      var PORT = '8888';
      this.categories = <loaded from websocket>;
    },
    selectCategory: function(event, detail, sender) {
      var elt = (event.target.nodeName == 'INPUT')? event.target.parentNode : event.target;
      this.values.selectedCategoryId = elt.dataset._id;
      this.$.globals.values.selectedCategoryId = elt.dataset._id;
      return false;
    }
  });
  </script>
</polymer-element>

当点击其中一个li元素时，'selectedCategoryId'会被更新。

这个值通过全局变量传递给最后一个元素'my-items.html'：

    <link rel="import" href="../bower_components/polymer/polymer.html">
<link rel="import" href="/Polymer/my-app/elements/app-globals.html">

<polymer-element name="my-items">
  <template>
    <app-globals id="globals"></app-globals>
    <style>
    </style>
    <div >selectedCategoryId = {{$.globals.values.selectedCategoryId}}</div>
    <ul>
      <template repeat="{{item in items}}"
                on-category-tap="{{handleCategoryTap}}">
        <li class="li-item" data-_id="{{item._id}}" on-click="{{selectItem}}">{{item.title}}</li>
      </template>
    </ul>
  </template>
  <script>
  Polymer('my-items', {
    values: {},
    ready: function() {
      var HOST = 'xxx.yyy.zzz.www';
      var PORT = '8888';
      console.log("'my-items' -> this.$.globals.values:");
      console.dir(this.$.globals.values);
      for(var prop in this.$.globals.values) {
        if(this.$.globals.values.hasOwnProperty(prop)) {
          console.log("this.$.globals.values[" + prop + "] = " + this.$.globals.values[prop] + "");
        }
      }
      console.log("'my-items' -> this.$.globals.values.selectedCategoryId = " + this.$.globals.values.selectedCategoryId);
    },
    handleCategoryTap: function(event) {...,
    selectItem: function(event) {...}
      return false;
    }  });
  </script>

给我带来了一些奇怪的东西： console.dir（this。$。globals.values）给出了相应的响应：对象{ selectedCategoryId：“547dfb6578be56f6630041a8” }

但是，选择此属性“selectedCategoryId”的结果为： console.log（“'my-items' - ＆gt; this。$。globals.values.selectedCategoryId =”+ this。$。globals.values.selectedCategoryId）; 给我： 'my-items' - ＆gt;这个。$。globals.values.selectedCategoryId = undefined undefined为什么？

Answer 1

我建议您使用：https://github.com/akc42/akc-meta

我确实使用它通过本地数据绑定在DOM之间共享信息！

如果您想要一个有效的示例，请参阅我的项目：https://github.com/MeTaNoV/firebase-element-extended

聚合物全局属性有些奇怪

1 个答案: