<iron-selector>, IronSelectableBehavior, IronMultiSelectableBehavior
iron-selector is an element which can be used to manage a list of elements
that can be selected. Tapping on the item will make the item selected. The
selected indicates which item is being selected. The default is to use the
index of the item. iron-selector's functionality is entirely defined by
IronMultiSelectableBehavior.
IronSelectableBehavior gives an element the concept of a selected child
element. By default, the element will select one of its selectable children
when a 'tap'
event
(synthesized by Polymer, roughly 'click') is dispatched to it.
IronSelectableBehavior lets you ...
- decide which children should be considered selectable (
selectable), - retrieve the currently selected element (
selectedItem) and all elements in the selectable set (items), - change the selection (
select,selectNext, etc.), - decide how selected elements are modified to indicate their selected state
(
selectedClass,selectedAttribute),
... among other things.
IronMultiSelectableBehavior includes all the features of
IronSelectableBehavior as well as a multi property, which can be set to
true to indicate that the element can have multiple selected child elements.
It also includes the selectedItems and selectedValues properties for
working with arrays of selectable elements and their corresponding values
(multi is true) - similar to the single-item versions provided by
IronSelectableBehavior: selectedItem and selected.
See: Documentation, Demo.
Usage
Installation
npm install --save @polymer/iron-selector
In an HTML file
<html>
<head>
<script type="module">
import '@polymer/iron-selector/iron-selector.js';
</script>
</head>
<body>
<iron-selector selected="0">
<div>Item 1</div>
<div>Item 2</div>
<div>Item 3</div>
</iron-selector>
</body>
</html>In a Polymer 3 element
import {PolymerElement} from '@polymer/polymer/polymer-element.js';
import {html} from '@polymer/polymer/lib/utils/html-tag.js';
import '@polymer/iron-selector/iron-selector.js';
class ExampleElement extends PolymerElement {
static get template() {
return html`
<iron-selector selected="0">
<div>Item 1</div>
<div>Item 2</div>
<div>Item 3</div>
</iron-selector>
`;
}
}
customElements.define('example-element', ExampleElement);Contributing
If you want to send a PR to this element, here are the instructions for running the tests and demo locally:
Installation
git clone https://github.com/PolymerElements/iron-selector
cd iron-selector
npm install
npm install -g polymer-cliRunning the demo locally
polymer serve --npm
open http://127.0.0.1:<port>/demo/Running the tests
polymer test --npm
