Menu
For illustration reasons, I've created a class inheriting from WebComponent called FancyOption that changes to a background color specified by text in one child element upon clicking another child element.
import 'package:web_ui/web_ui.dart';
import 'dart:html';
class FancyOptionComponent extends WebComponent {
ButtonElement _button;
TextInputElement _textInput;
FancyOptionComponent() {
// obtain reference to button element
// obtain reference to text element
// failed attempt
//_button = this.query('.fancy-option-button');
// error: Bad state: host element has not been set. (no idea)
// make the background color of this web component the specified color
final changeColorFunc = (e) => this.style.backgroundColor = _textInput.value;
_button.onClick.listen(changeColorFunc);
}
}
FancyOption HTML:
<!DOCTYPE html>
<html>
<body>
<element name="x-fancy-option" constructor="FancyOptionComponent" extends="div">
<template>
<div>
<button class='fancy-option-button'>Click me!</button>
<input class='fancy-option-text' type='text'>
</div>
</template>
<script type="application/dart" src="fancyoption.dart"></script>
</element>
</body>
</html>
I have three of them on a page like this.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Sample app</title>
<link rel="stylesheet" href="myapp.css">
<link rel="components" href="fancyoption.html">
</head>
<body>
<h3>Type a color name into a fancy option textbox, push the button and
see what happens!</h3>
<div is="x-fancy-option" id="fancy-option1"></div>
<div is="x-fancy-option" id="fancy-option2"></div>
<div is="x-fancy-option" id="fancy-option3"></div>
<script type="application/dart" src="myapp.dart"></script>
<script src="packages/browser/dart.js"></script>
</body>
</html>
469
Just use getShadowRoot() and query against it:
import 'package:web_ui/web_ui.dart';
import 'dart:html';
class FancyOptionComponent extends WebComponent {
ButtonElement _button;
TextInputElement _textInput;
inserted() {
// obtain references
_button = getShadowRoot('x-fancy-option').query('.fancy-option-button');
_textInput = getShadowRoot('x-fancy-option').query('.fancy-option-text');
// make the background color of this web component the specified color
final changeColorFunc = (e) => this.style.backgroundColor = _textInput.value;
_button.onClick.listen(changeColorFunc);
}
}
Where x-fancy-option string is the name of the element.
Note: I changed your constructor to be inserted() method, which is a life cycle method.
78
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
