paper-radio-group.html

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<!--
`paper-radio-group` allows user to select only one radio button from a set.
Checking one radio button that belongs to a radio group unchecks any 
previously checked radio button within the same group. Use
`selected` to get or set the selected radio button.

Example:

    <paper-radio-group selected="small">
      <paper-radio-button name="small" label="Small"></paper-radio-button>
      <paper-radio-button name="medium" label="Medium"></paper-radio-button>
      <paper-radio-button name="large" label="Large"></paper-radio-button>
    </paper-radio-group>

See <a href="paper-radio-button.html">paper-radio-button</a> for more
information about `paper-radio-button`.

@group Paper Elements
@element paper-radio-group
@extends core-selector
@homepage github.io
-->

<link rel="import" href="../core-a11y-keys/core-a11y-keys.html">
<link rel="import" href="../core-selector/core-selector.html">
<link rel="import" href="../paper-radio-button/paper-radio-button.html">

<polymer-element name="paper-radio-group" extends="core-selector" role="radiogroup">

  <template>

    <core-a11y-keys target="{{}}" keys="up left" on-keys-pressed="{{selectPrevious}}"></core-a11y-keys>
    <core-a11y-keys target="{{}}" keys="down right" on-keys-pressed="{{selectNext}}"></core-a11y-keys>
  
    <style>
    
      :host {
        display: inline-block;
      }
  
      polyfill-next-selector { content: ':host > *'; }
      ::content > * {
        padding: 12px;
      }
    
    </style>
  
    <shadow></shadow>
    
  </template>
  
  <script>
  
    Polymer('paper-radio-group', {
      nextIndex: function(index) {
        var items = this.items;
        var newIndex = index;
        do {
          newIndex = (newIndex + 1) % items.length;
          if (newIndex === index) {
            break;
          }
        } while (items[newIndex].disabled);
        return newIndex;
      },
      previousIndex: function(index) {
        var items = this.items;
        var newIndex = index;
        do {
          newIndex = (newIndex || items.length) - 1;
          if (newIndex === index) {
            break;
          }
        } while (items[newIndex].disabled);
        return newIndex;
      },
      selectNext: function() {
        var node = this.selectIndex(this.nextIndex(this.selectedIndex));
        node.focus();
      },
      selectPrevious: function() {
        var node = this.selectIndex(this.previousIndex(this.selectedIndex));
        node.focus();
      },
      
      /**
       * Specifies the attribute to set on the selected element to indicate
       * its active state.
       *
       * @attribute selectedAttribute
       * @type string
       * @default 'checked'
       */
      selectedAttribute: 'checked',
      
      /**
       * The event that would be fired from the item element to indicate
       * it is being selected.
       *
       * @attribute activateEvent
       * @type string
       * @default 'change'
       */
      activateEvent: 'change'

    });
  
  </script>
  
</polymer-element>