为什么聚合物元素<paper-button>不渲染

Question

为什么 <paper-button> 没有渲染？其他一切正常，并呈现带有 id=button1 的按钮。我尝试使用不同的路径：

<link rel="import" href="../../packages/paper_elements/paper_button.html">

但还是不行。我正在使用飞镖 1.91 聚合物 polymer:0.16.0+7 paper_elements :0.6.2+3

//***************INDEX.HTML FILE 
<!DOCTYPE html>

<html>
<head>
<meta charset="utf-8">
<link rel="stylesheet" href="styles/main.css">
<link rel="import" href="packages/polymer/polymer.html">
<link rel="import" href="packages/paper_elements/paper_button.html">
<script src="packages/browser/dart.js"></script>
<script type="application/dart" src="main.dart"></script>

<title>Test my polymetr test 152</title>
</head>

<body unresolved>
  <h1 id="output">the output div</h1>
  <label id="hello">hello vr y31</label>
  <button id="button1">Enter button</button>
  <paper-button></paper-button>
</body>
</html>

//***************MAIN.DART FILE 
// Copyright (c) 2015, <your name>. All rights reserved. Use of this source code
// is governed by a BSD-style license that can be found in the LICENSE file.

import 'dart:html';
import "dart:async";
import 'package:polymer/polymer.dart';

void main() {
   void realMain() {
    Element abc=querySelector("#output");
    abc.text="Up and running";
  };

  initPolymer().then((zone) => zone.run(realMain));
  Element button1=querySelector("#button1");
  button1.onClick.listen(buttonClick);
}

void buttonClick(Event e){
  (e.target as ButtonElement).text='Clicked button';
}

//***************PUPSPEC.YAML file
name: Atests
version: 0.0.1
description: An absolute bare-bones web app.
environment:
  sdk: '>=1.0.0 <2.0.0'
dependencies:
  browser: any
  paper_elements: 0.6.2+3
  polymer: '>=0.16.0+7 <0.17.0'
transformers:
- polymer:
    entry_points: web/index.html

Answer 1

如果您添加一些文本 ((<paper-button>xxx</paper-button>)，您会看到按钮在那里，只是不可见。此外，当您调查 Chrome dev 中的 DOM tools 你会看到 <paper-button> 元素在那里并且还有一个阴影 DOM（如果你在开发工具设置中激活以显示阴影 DOM），这表明该元素已正确初始化. 即使不添加文本，您也可以单击按钮（就在 [Enter 按钮] 的右侧，您会看到涟漪效果。

为什么聚合物元素<paper-button>不渲染

Why is the polymer element <paper-button> not rendering

dart

dart-polymer