Javascript 纸张无线电组仅在第二次单击时进行选择

这可能很简单，但我现在无法理解。我有一个带有各种按钮的聚合物纸单选组，但直到第二次单击才进行选择

<paper-radio-group selected="{{radioSelected}}" on-change="viewChanger">
    <paper-radio-button name="none">None</paper-radio-button>
    <paper-radio-button name="sidebyside">Side by side</paper-radio-button>
    <paper-radio-button name="popup">Pop-up</paper-radio-button>
</paper-radio-group>

谢谢你的帮助。我对聚合物还不熟悉。

试试这个：

<paper-radio-group selected="{{radioSelected}}">
  <paper-radio-button name="none">None</paper-radio-button>
  <paper-radio-button name="sidebyside">Side by side</paper-radio-button>
  <paper-radio-button name="popup">Pop-up</paper-radio-button>
</paper-radio-group>

---

你能把问题放在这里吗？很 完美！非常感谢！

<paper-radio-group selected="{{radioSelected}}">
  <paper-radio-button name="none">None</paper-radio-button>
  <paper-radio-button name="sidebyside">Side by side</paper-radio-button>
  <paper-radio-button name="popup">Pop-up</paper-radio-button>
</paper-radio-group>

Polymer({
  is: 'x-menu',
  properties: {

    radioSelected: {
      type: String,
      value: "none",
      observer: '_radioGroupChanged'
    }
  },

  _radioGroupChanged: function(radioSelected) {
    console.log(radioSelected);
  }
});