Creating a group of paper-checkbox (using iron-selector?) - polymer

Question

My goal is to group a set of paper-checkbox.
For paper-ratio-button, I am doing:
<paper-radio-group selected="foo">
<paper-radio-button name="foo">Foo</paper-radio-button>
<paper-radio-button name="bar">Bar</paper-radio-button>
</paper-radio-group>
For paper-checkbox, I would have expected to use iron-selector:
<iron-selector attr-for-selected="name" selected="foo">
<paper-checkbox name="foo">Foo</paper-checkbox>
<paper-checkbox name="bar">Bar</paper-checkbox>
</iron-selector>
But this does not work, the checkbox with name=foo is not selected

Answer 1

I got it working, I was missing selected-attribute="checked":
<iron-selector attr-for-selected="name" selected="foo" selected-attribute="checked">
<paper-checkbox name="foo">Foo</paper-checkbox>
<paper-checkbox name="bar">Bar</paper-checkbox>
</iron-selector>
To allow multiple selection, use <iron-selector attr-for-selected="name" multi selected-values='["foo","bar"]' selected-attribute="checked">

Answer 2

You have to write your own little element. It's not that hard.. just something to start with:
parent
<my-el selected="foo">
<paper-checkbox name="foo"></paper-checkbox>
<paper-checkbox name="bar"></paper-checkbox>
<paper-checkbox name="foobar"></paper-checkbox>
</my-el>
my-el
<dom-module id="my-el">
<template>
<slot></slot>
</template>
<script>
Polymer({
is: 'my-el',
properties: {
selected: {
type: String,
observer: "_selectCheckboxes"
}
},
_selectCheckboxes() {
var checkboxes = this.$.slotted.getDistributedNodes();
this.reset(checkboxes);
for (var i = 0; i = checkboxes.length; i++) {
var obj = checkboxes[i];
if(obj.getAttribute("name") == value) {
obj.checked = true;
}
}
},
reset: function(obj) {
for (var i = 0; i = obj.length; i++) {
obj[i].checked = false;
}
return true;
}
});
</script>
</dom-module>
I hope that this will help you. Off course that you have to implement a little bit more logic to make it work. If you have more questions about it just ask, and i can edit my answer.
A little explanation: https://www.polymer-project.org/2.0/docs/upgrade
By the way: I assume you are using Polymer version >= 1.7.0. For older versions you have to use <content> element instead of <slot> and different selector