paper-dialog-behavior.html

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<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-overlay-behavior/iron-overlay-behavior.html">
<link rel="import" href="../iron-flex-layout/iron-flex-layout.html">
<link rel="import" href="../paper-styles/default-theme.html">
<link rel="import" href="../paper-styles/typography.html">
<link rel="import" href="../paper-styles/shadow.html">

<script>

/**
Use `Polymer.PaperDialogBehavior` and `paper-dialog-shared-styles.html` to implement a Material Design
dialog.

For example, if `<paper-dialog-impl>` implements this behavior:

    <paper-dialog-impl>
        <h2>Header</h2>
        <div>Dialog body</div>
        <div class="buttons">
            <paper-button dialog-dismiss>Cancel</paper-button>
            <paper-button dialog-confirm>Accept</paper-button>
        </div>
    </paper-dialog-impl>

`paper-dialog-shared-styles.html` provide styles for a header, content area, and an action area for buttons.
Use the `<h2>` tag for the header and the `buttons` class for the action area. You can use the
`paper-dialog-scrollable` element (in its own repository) if you need a scrolling content area.

Use the `dialog-dismiss` and `dialog-confirm` attributes on interactive controls to close the
dialog. If the user dismisses the dialog with `dialog-confirm`, the `closingReason` will update
to include `confirmed: true`.

### Styling

The following custom properties and mixins are available for styling.

Custom property | Description | Default
----------------|-------------|----------
`--paper-dialog-background-color` | Dialog background color                     | `--primary-background-color`
`--paper-dialog-color`            | Dialog foreground color                     | `--primary-text-color`
`--paper-dialog`                  | Mixin applied to the dialog                 | `{}`
`--paper-dialog-title`            | Mixin applied to the title (`<h2>`) element | `{}`
`--paper-dialog-button-color`     | Button area foreground color                | `--default-primary-color`

### Accessibility

This element has `role="dialog"` by default. Depending on the context, it may be more appropriate
to override this attribute with `role="alertdialog"`.

If `modal` is set, the element will set `aria-modal` and prevent the focus from exiting the element.
It will also ensure that focus remains in the dialog.

The `aria-labelledby` attribute will be set to the header element, if one exists.

@hero hero.svg
@demo demo/index.html
@polymerBehavior Polymer.PaperDialogBehavior
*/

  Polymer.PaperDialogBehaviorImpl = {

    hostAttributes: {
      'role': 'dialog',
      'tabindex': '-1'
    },

    properties: {

      /**
       * If `modal` is true, this implies `no-cancel-on-outside-click`, `no-cancel-on-esc-key` and `with-backdrop`.
       */
      modal: {
        type: Boolean,
        value: false
      }

    },

    observers: [
      '_modalChanged(modal, _readied)'
    ],

    listeners: {
      'tap': '_onDialogClick'
    },

    ready: function () {
      // Only now these properties can be read.
      this.__prevNoCancelOnOutsideClick = this.noCancelOnOutsideClick;
      this.__prevNoCancelOnEscKey = this.noCancelOnEscKey;
      this.__prevWithBackdrop = this.withBackdrop;
    },

    attached: function() {
      // this._observer is used by iron-overlay-behavior
      this._ariaObserver = Polymer.dom(this).observeNodes(this._updateAriaLabelledBy);
      this._updateAriaLabelledBy();
    },

    detached: function() {
      Polymer.dom(this).unobserveNodes(this._ariaObserver);
    },

    _modalChanged: function(modal, readied) {
      if (modal) {
        this.setAttribute('aria-modal', 'true');
      } else {
        this.setAttribute('aria-modal', 'false');
      }

      // modal implies noCancelOnOutsideClick, noCancelOnEscKey and withBackdrop.
      // We need to wait for the element to be ready before we can read the
      // properties values.
      if (!readied) {
        return;
      }

      if (modal) {
        this.__prevNoCancelOnOutsideClick = this.noCancelOnOutsideClick;
        this.__prevNoCancelOnEscKey = this.noCancelOnEscKey;
        this.__prevWithBackdrop = this.withBackdrop;
        this.noCancelOnOutsideClick = true;
        this.noCancelOnEscKey = true;
        this.withBackdrop = true;
      } else {
        // If the value was changed to false, let it false.
        this.noCancelOnOutsideClick = this.noCancelOnOutsideClick &&
          this.__prevNoCancelOnOutsideClick;
        this.noCancelOnEscKey = this.noCancelOnEscKey &&
          this.__prevNoCancelOnEscKey;
        this.withBackdrop = this.withBackdrop && this.__prevWithBackdrop;
      }
    },

    _updateAriaLabelledBy: function() {
      var header = Polymer.dom(this).querySelector('h2');
      if (!header) {
        this.removeAttribute('aria-labelledby');
        return;
      }
      var headerId = header.getAttribute('id');
      if (headerId && this.getAttribute('aria-labelledby') === headerId) {
        return;
      }
      // set aria-describedBy to the header element
      var labelledById;
      if (headerId) {
        labelledById = headerId;
      } else {
        labelledById = 'paper-dialog-header-' + new Date().getUTCMilliseconds();
        header.setAttribute('id', labelledById);
      }
      this.setAttribute('aria-labelledby', labelledById);
    },

    _updateClosingReasonConfirmed: function(confirmed) {
      this.closingReason = this.closingReason || {};
      this.closingReason.confirmed = confirmed;
    },

    /**
     * Will dismiss the dialog if user clicked on an element with dialog-dismiss
     * or dialog-confirm attribute.
     */
    _onDialogClick: function(event) {
      // Search for the element with dialog-confirm or dialog-dismiss,
      // from the root target until this (excluded).
      var path = Polymer.dom(event).path;
      for (var i = 0; i < path.indexOf(this); i++) {
        var target = path[i];
        if (target.hasAttribute && (target.hasAttribute('dialog-dismiss') || target.hasAttribute('dialog-confirm'))) {
          this._updateClosingReasonConfirmed(target.hasAttribute('dialog-confirm'));
          this.close();
          event.stopPropagation();
          break;
        }
      }
    }

  };

  /** @polymerBehavior */
  Polymer.PaperDialogBehavior = [Polymer.IronOverlayBehavior, Polymer.PaperDialogBehaviorImpl];

</script>