anypoint-radio-group.html

<!--
@license
Copyright 2017 Mulesoft.

All rights reserved.
-->
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
<link rel="import" href="../iron-menu-behavior/iron-menubar-behavior.html">
<link rel="import" href="../anypoint-radio-button/anypoint-radio-button.html">
<!--
`<anypoint-radio-group>` A group of Anypoint radio buttons

`anypoint-radio-group` allows user to select at most 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.
The `<anypoint-radio-buttons>` inside the group must have the `name` attribute
set.

Example:
```html
<anypoint-radio-group selected="small">
  <anypoint-radio-button name="small">Small</anypoint-radio-button>
  <anypoint-radio-button name="medium">Medium</anypoint-radio-button>
  <anypoint-radio-button name="large">Large</anypoint-radio-button>
</anypoint-radio-group>
```

Radio-button-groups can be made optional, and allow zero buttons to be selected:

```html
<anypoint-radio-group selected="small" allow-empty-selection>
  <anypoint-radio-button name="small">Small</anypoint-radio-button>
  <anypoint-radio-button name="medium">Medium</anypoint-radio-button>
  <anypoint-radio-button name="large">Large</anypoint-radio-button>
</anypoint-radio-group>
```

See `anypoint-radio-buttonz for more information.

### Styling

Custom property | Description | Default
----------------|-------------|----------
`--anypoint-radio-group-item-padding` | The padding of the item | `12px`

@group Anypoint Elements
@element anypoint-radio-group
@demo demo/index.html
-->
<dom-module id="anypoint-radio-group">
  <template>
    <style>
    :host {
      display: inline-block;
    }

    :host ::content > * {
      padding: var(--anypoint-radio-group-item-padding, 12px);
    }
    </style>
    <content id="items" select="*"></content>
  </template>
  <script>
  Polymer({
    is: 'anypoint-radio-group',

    behaviors: [
      Polymer.IronMenubarBehavior
    ],

    hostAttributes: {
      role: 'radiogroup',
      tabindex: 0
    },
    /**
     * Fired when the radio group selection changes.
     *
     * @event anypoint-radio-group-changed
     */
    properties: {
      /**
       * Overriden from Polymer.IronSelectableBehavior
       */
      attrForSelected: {
        type: String,
        value: 'name'
      },
      /**
       * Overriden from Polymer.IronSelectableBehavior
       */
      selectedAttribute: {
        type: String,
        value: 'checked'
      },
      /**
       * Overriden from Polymer.IronSelectableBehavior
       */
      selectable: {
        type: String,
        value: 'anypoint-radio-button'
      },
      /**
       * If true, radio-buttons can be deselected
       */
      allowEmptySelection: {
        type: Boolean,
        value: false
      }
    },

    /**
     * Selects the given value.
     */
    select: function(value) {
      var newItem = this._valueToItem(value);
      if (newItem && newItem.hasAttribute('disabled')) {
        return;
      }
      if (this.selected) {
        var oldItem = this._valueToItem(this.selected);
        if (this.selected === value) {
          // If deselecting is allowed we'll have to apply an empty selection.
          // Otherwise, we should force the selection to stay and make this
          // action a no-op.
          if (this.allowEmptySelection) {
            value = '';
          } else {
            if (oldItem) {
              oldItem.checked = true;
            }
            return;
          }
        }
        if (oldItem) {
          oldItem.checked = false;
        }
      }
      Polymer.IronSelectableBehavior.select.apply(this, [value]);
      this.fire('anypoint-radio-group-changed');
    },
    _activateFocusedItem: function() {
      this._itemActivate(this._valueForItem(this.focusedItem), this.focusedItem);
    },

    _onUpKey: function(event) {
      this._focusPrevious();
      event.preventDefault();
      this._activateFocusedItem();
    },

    _onDownKey: function(event) {
      this._focusNext();
      event.preventDefault();
      this._activateFocusedItem();
    },

    _onLeftKey: function() {
      Polymer.IronMenubarBehaviorImpl._onLeftKey.apply(this, arguments);
      this._activateFocusedItem();
    },

    _onRightKey: function() {
      Polymer.IronMenubarBehaviorImpl._onRightKey.apply(this, arguments);
      this._activateFocusedItem();
    }
  });
  </script>
</dom-module>