jellyfin-web/dashboard-ui/bower_components/iron-menu-behavior/iron-menu-behavior.html
2016-07-07 14:12:08 -04:00

337 lines
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HTML

<!--
@license
Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
Code distributed by Google as part of the polymer project is also
subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
-->
<link rel="import" href="../polymer/polymer.html">
<link rel="import" href="../iron-selector/iron-multi-selectable.html">
<link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
<script>
/**
* `Polymer.IronMenuBehavior` implements accessible menu behavior.
*
* @demo demo/index.html
* @polymerBehavior Polymer.IronMenuBehavior
*/
Polymer.IronMenuBehaviorImpl = {
properties: {
/**
* Returns the currently focused item.
* @type {?Object}
*/
focusedItem: {
observer: '_focusedItemChanged',
readOnly: true,
type: Object
},
/**
* The attribute to use on menu items to look up the item title. Typing the first
* letter of an item when the menu is open focuses that item. If unset, `textContent`
* will be used.
*/
attrForItemTitle: {
type: String
}
},
hostAttributes: {
'role': 'menu',
'tabindex': '0'
},
observers: [
'_updateMultiselectable(multi)'
],
listeners: {
'focus': '_onFocus',
'keydown': '_onKeydown',
'iron-items-changed': '_onIronItemsChanged'
},
keyBindings: {
'up': '_onUpKey',
'down': '_onDownKey',
'esc': '_onEscKey',
'shift+tab:keydown': '_onShiftTabDown'
},
attached: function() {
this._resetTabindices();
},
/**
* Selects the given value. If the `multi` property is true, then the selected state of the
* `value` will be toggled; otherwise the `value` will be selected.
*
* @param {string|number} value the value to select.
*/
select: function(value) {
// Cancel automatically focusing a default item if the menu received focus
// through a user action selecting a particular item.
if (this._defaultFocusAsync) {
this.cancelAsync(this._defaultFocusAsync);
this._defaultFocusAsync = null;
}
var item = this._valueToItem(value);
if (item && item.hasAttribute('disabled')) return;
this._setFocusedItem(item);
Polymer.IronMultiSelectableBehaviorImpl.select.apply(this, arguments);
},
/**
* Resets all tabindex attributes to the appropriate value based on the
* current selection state. The appropriate value is `0` (focusable) for
* the default selected item, and `-1` (not keyboard focusable) for all
* other items.
*/
_resetTabindices: function() {
var selectedItem = this.multi ? (this.selectedItems && this.selectedItems[0]) : this.selectedItem;
this.items.forEach(function(item) {
item.setAttribute('tabindex', item === selectedItem ? '0' : '-1');
}, this);
},
/**
* Sets appropriate ARIA based on whether or not the menu is meant to be
* multi-selectable.
*
* @param {boolean} multi True if the menu should be multi-selectable.
*/
_updateMultiselectable: function(multi) {
if (multi) {
this.setAttribute('aria-multiselectable', 'true');
} else {
this.removeAttribute('aria-multiselectable');
}
},
/**
* Given a KeyboardEvent, this method will focus the appropriate item in the
* menu (if there is a relevant item, and it is possible to focus it).
*
* @param {KeyboardEvent} event A KeyboardEvent.
*/
_focusWithKeyboardEvent: function(event) {
for (var i = 0, item; item = this.items[i]; i++) {
var attr = this.attrForItemTitle || 'textContent';
var title = item[attr] || item.getAttribute(attr);
if (!item.hasAttribute('disabled') && title &&
title.trim().charAt(0).toLowerCase() === String.fromCharCode(event.keyCode).toLowerCase()) {
this._setFocusedItem(item);
break;
}
}
},
/**
* Focuses the previous item (relative to the currently focused item) in the
* menu, disabled items will be skipped.
* Loop until length + 1 to handle case of single item in menu.
*/
_focusPrevious: function() {
var length = this.items.length;
var curFocusIndex = Number(this.indexOf(this.focusedItem));
for (var i = 1; i < length + 1; i++) {
var item = this.items[(curFocusIndex - i + length) % length];
if (!item.hasAttribute('disabled')) {
this._setFocusedItem(item);
return;
}
}
},
/**
* Focuses the next item (relative to the currently focused item) in the
* menu, disabled items will be skipped.
* Loop until length + 1 to handle case of single item in menu.
*/
_focusNext: function() {
var length = this.items.length;
var curFocusIndex = Number(this.indexOf(this.focusedItem));
for (var i = 1; i < length + 1; i++) {
var item = this.items[(curFocusIndex + i) % length];
if (!item.hasAttribute('disabled')) {
this._setFocusedItem(item);
return;
}
}
},
/**
* Mutates items in the menu based on provided selection details, so that
* all items correctly reflect selection state.
*
* @param {Element} item An item in the menu.
* @param {boolean} isSelected True if the item should be shown in a
* selected state, otherwise false.
*/
_applySelection: function(item, isSelected) {
if (isSelected) {
item.setAttribute('aria-selected', 'true');
} else {
item.removeAttribute('aria-selected');
}
Polymer.IronSelectableBehavior._applySelection.apply(this, arguments);
},
/**
* Discretely updates tabindex values among menu items as the focused item
* changes.
*
* @param {Element} focusedItem The element that is currently focused.
* @param {?Element} old The last element that was considered focused, if
* applicable.
*/
_focusedItemChanged: function(focusedItem, old) {
old && old.setAttribute('tabindex', '-1');
if (focusedItem) {
focusedItem.setAttribute('tabindex', '0');
focusedItem.focus();
}
},
/**
* A handler that responds to mutation changes related to the list of items
* in the menu.
*
* @param {CustomEvent} event An event containing mutation records as its
* detail.
*/
_onIronItemsChanged: function(event) {
if (event.detail.addedNodes.length) {
this._resetTabindices();
}
},
/**
* Handler that is called when a shift+tab keypress is detected by the menu.
*
* @param {CustomEvent} event A key combination event.
*/
_onShiftTabDown: function(event) {
var oldTabIndex = this.getAttribute('tabindex');
Polymer.IronMenuBehaviorImpl._shiftTabPressed = true;
this._setFocusedItem(null);
this.setAttribute('tabindex', '-1');
this.async(function() {
this.setAttribute('tabindex', oldTabIndex);
Polymer.IronMenuBehaviorImpl._shiftTabPressed = false;
// NOTE(cdata): polymer/polymer#1305
}, 1);
},
/**
* Handler that is called when the menu receives focus.
*
* @param {FocusEvent} event A focus event.
*/
_onFocus: function(event) {
if (Polymer.IronMenuBehaviorImpl._shiftTabPressed) {
// do not focus the menu itself
return;
}
// Do not focus the selected tab if the deepest target is part of the
// menu element's local DOM and is focusable.
var rootTarget = /** @type {?HTMLElement} */(
Polymer.dom(event).rootTarget);
if (rootTarget !== this && typeof rootTarget.tabIndex !== "undefined" && !this.isLightDescendant(rootTarget)) {
return;
}
// clear the cached focus item
this._defaultFocusAsync = this.async(function() {
// focus the selected item when the menu receives focus, or the first item
// if no item is selected
var selectedItem = this.multi ? (this.selectedItems && this.selectedItems[0]) : this.selectedItem;
this._setFocusedItem(null);
if (selectedItem) {
this._setFocusedItem(selectedItem);
} else if (this.items[0]) {
// We find the first none-disabled item (if one exists)
this._focusNext();
}
});
},
/**
* Handler that is called when the up key is pressed.
*
* @param {CustomEvent} event A key combination event.
*/
_onUpKey: function(event) {
// up and down arrows moves the focus
this._focusPrevious();
event.detail.keyboardEvent.preventDefault();
},
/**
* Handler that is called when the down key is pressed.
*
* @param {CustomEvent} event A key combination event.
*/
_onDownKey: function(event) {
this._focusNext();
event.detail.keyboardEvent.preventDefault();
},
/**
* Handler that is called when the esc key is pressed.
*
* @param {CustomEvent} event A key combination event.
*/
_onEscKey: function(event) {
// esc blurs the control
this.focusedItem.blur();
},
/**
* Handler that is called when a keydown event is detected.
*
* @param {KeyboardEvent} event A keyboard event.
*/
_onKeydown: function(event) {
if (!this.keyboardEventMatchesKeys(event, 'up down esc')) {
// all other keys focus the menu item starting with that character
this._focusWithKeyboardEvent(event);
}
event.stopPropagation();
},
// override _activateHandler
_activateHandler: function(event) {
Polymer.IronSelectableBehavior._activateHandler.call(this, event);
event.stopPropagation();
}
};
Polymer.IronMenuBehaviorImpl._shiftTabPressed = false;
/** @polymerBehavior Polymer.IronMenuBehavior */
Polymer.IronMenuBehavior = [
Polymer.IronMultiSelectableBehavior,
Polymer.IronA11yKeysBehavior,
Polymer.IronMenuBehaviorImpl
];
</script>