Polymer's paper-dialog not working can't be opened - polymer

Question

I am trying to implement a paper-dialog box that will reveal itself when a paper-fab is tapped in the image below:
my app's main screen
but I can't get the paper-dialog to open.
I have implemented paper-dialog into my app as following:
<link rel="import" href="../bower_components/polymer/polymer.html">
<link rel="import" href="../bower_components/polymerfire/firebase-query.html">
<link rel="import" href="../bower_components/paper-fab/paper-fab.html">
<link rel="import" href="../bower_components/paper-dialog/paper-dialog.html">
<link rel="import" href="../bower_components/polymerfire/firebase-auth.html">
<link rel="import" href="shared-styles.html">
<dom-module id="my-view1">
<template>
<style include="shared-styles">
:host {
display: block;
padding: 10px;
}
paper-fab{
position:fixed;
right:20px;
bottom:68px;
--paper-fab-keyboard-focus-background:--accent-color;
}
</style>
<firebase-auth
id="auth"
user="{{user}}"
provider=""
status-known="{{statusKnown}}"
on-error="handleError">
</firebase-auth>
<firebase-query
id="query"
path="/posts"
data="{{posts}}">
</firebase-query>
<div class="card">
<h1>Post</h1>
<ul id="post-list">
<template is="dom-repeat" items="[[posts]]" as="post">
<li>
<p class="content">[[post.body]]</p>
</li>
</template>
</ul>
</div>
<paper-fab icon="add" onclick="dialog.open()"></paper-fab>
<paper-dialog id="dialog">
<paper-textarea id="post" label="Write your post here..."></paper-textarea>
<paper-button dialog-dismiss>Cancel</paper-button>
<paper-button on-tap="post" id="btnPost" raised class="indigo" hidden$="[[!user]]">Post</paper-button>
</paper-dialog>
</template>
<script>
Polymer({
is: 'my-view1',
properties:{
user:{
type: Object
},
statusKnown:{
type: Object
},
posts: {
type: Object
}
},
post: function() {
this.$.query.ref.push({
"Uid": this.user.uid,
"body": this.$.post.value
});
this.$.post.value = null;
}
});
</script>
</dom-module>
<paper-fab icon="add" onclick="dialog.open()"></paper-fab>
<paper-dialog id="dialog">
<paper-textarea id="post" label="Write your post here..."></paper-textarea>
<paper-button dialog-dismiss>Cancel</paper-button>
<paper-button on-tap="post" id="btnPost" raised class="indigo" hidden$="[[!user]]">Post</paper-button>
</paper-dialog>
This snippet here are taken from the demo on this page:
https://www.webcomponents.org/element/PolymerElements/paper-dialog/v1.1.0/demo/demo/index.html
but when I actually tap on the paper-fab, I get the following error:
Uncaught ReferenceError: dialog is not defined
at HTMLElement.onclick (view3:1)
onclick # view3:1
Does anyone have any idea how I can make the paper-dialog open when the paper-fab is tapped? I suppose I am missing some includes, but I cannot figure out which one.

Answer 1

at first, don't use onclick. There are Polymer event attributes like on-click or on-tap. Second, you should call function which will open the selected dialog
Example:
<paper-fab icon="add" on-tap="_openDialog"></paper-fab>
and inside script
_openDialog: function() {
this.$.dialog.open();
}
this.$.dialog find element with id dialog and call function open