iron-collapse.html
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<!--
@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">
<!--
`iron-collapse` creates a collapsible block of content. By default, the content
will be collapsed. Use `opened` or `toggle()` to show/hide the content.
<button on-click="{{toggle}}">toggle collapse</button>
<iron-collapse id="collapse">
<div>Content goes here...</div>
</iron-collapse>
...
toggle: function() {
this.$.collapse.toggle();
}
`iron-collapse` adjusts the height/width of the collapsible element to show/hide
the content. So avoid putting padding/margin/border on the collapsible directly,
and instead put a div inside and style that.
<style>
.collapse-content {
padding: 15px;
border: 1px solid #dedede;
}
</style>
<iron-collapse>
<div class="collapse-content">
<div>Content goes here...</div>
</div>
</iron-collapse>
@group Iron Elements
@hero hero.svg
@demo demo/index.html
@element iron-collapse
-->
<dom-module id="iron-collapse">
<style>
:host {
display: block;
transition-duration: 300ms;
}
:host(.iron-collapse-closed) {
display: none;
}
:host(:not(.iron-collapse-opened)) {
overflow: hidden;
}
</style>
<template>
<content></content>
</template>
</dom-module>
<script>
Polymer({
is: 'iron-collapse',
properties: {
/**
* If true, the orientation is horizontal; otherwise is vertical.
*
* @attribute horizontal
*/
horizontal: {
type: Boolean,
value: false,
observer: '_horizontalChanged'
},
/**
* Set opened to true to show the collapse element and to false to hide it.
*
* @attribute opened
*/
opened: {
type: Boolean,
value: false,
notify: true,
observer: '_openedChanged'
}
},
hostAttributes: {
role: 'group',
'aria-expanded': 'false'
},
listeners: {
transitionend: '_transitionEnd'
},
ready: function() {
// Avoid transition at the beginning e.g. page loads and enable
// transitions only after the element is rendered and ready.
this._enableTransition = true;
},
/**
* Toggle the opened state.
*
* @method toggle
*/
toggle: function() {
this.opened = !this.opened;
},
show: function() {
this.toggleClass('iron-collapse-closed', false);
this.updateSize('auto', false);
var s = this._calcSize();
this.updateSize('0px', false);
// force layout to ensure transition will go
this.offsetHeight;
this.updateSize(s, true);
},
hide: function() {
this.toggleClass('iron-collapse-opened', false);
this.updateSize(this._calcSize(), false);
// force layout to ensure transition will go
this.offsetHeight;
this.updateSize('0px', true);
},
updateSize: function(size, animated) {
this.enableTransition(animated);
var s = this.style;
var nochange = s[this.dimension] === size;
s[this.dimension] = size;
if (animated && nochange) {
this._transitionEnd();
}
},
enableTransition: function(enabled) {
this.style.transitionDuration = (enabled && this._enableTransition) ? '' : '0s';
},
_horizontalChanged: function() {
this.dimension = this.horizontal ? 'width' : 'height';
this.style.transitionProperty = this.dimension;
},
_openedChanged: function() {
this[this.opened ? 'show' : 'hide']();
this.setAttribute('aria-expanded', this.opened ? 'true' : 'false');
},
_transitionEnd: function() {
if (this.opened) {
this.updateSize('auto', false);
}
this.toggleClass('iron-collapse-closed', !this.opened);
this.toggleClass('iron-collapse-opened', this.opened);
this.enableTransition(false);
},
_calcSize: function() {
return this.getBoundingClientRect()[this.dimension] + 'px';
},
});
</script>