dart - 在Dart中添加事件监听器以获取 polymer 中的事件

Question

需要从dart包 core_elements 中的 core-scroll-header-panel 元素添加 core-header-transform 的事件侦听器。我该怎么做？

app.html:

<template>
  <core-scroll-header-panel id="scroll-panel" condenses flex>
    <core-toolbar class="tall">
        <header id="main-header" horizontal layout flex>
            <div id="application-name">
                status
                <server-status></server-status>
            </div>
        </header>
      <div class="bottom indent title">title</div>
    </core-toolbar> </template>

Dart app.dart:

import 'package:polymer/polymer.dart';

@CustomTag('some-app')
class SomeApp extends PolymerElement {
  Some.created() : super.created();

  onReady(){
    var coreScrollHeader = $['scroll-panel'];

    coreScrollHeader.on['core-header-transform'].listen((event){
      print('core-header-transform');
    });
  }
}

在 pubspec.yaml中:聚合物:“^ 0.16.3 + 3”

Answer 1

首先，确保Polymer已正确初始化(有关详细信息，请参见how to implement a main function in polymer apps)

注册事件侦听器，例如:

  @whenPolymerReady
  onReady(){
    var coreScrollHeader = querySelector('* /deep/ #scroll-panel');

    coreScrollHeader.on['core-header-transform'].listen((event){
      print('core-header-transform');
    });
  }