The principle and implementation of the Polymer framework in the Java class library
The Polymer framework is a front -end development framework based on the web component standard. It can help developers quickly build high -performance, reused, and easy -to -maintain web applications.Polymer's design concept is to build applications by packaging, reuse, and customized web components.
The implementation principle of the Polymer framework is mainly based on the following aspects:
1. Web component standard: The Polymer framework uses the web component standard, including custom elements and Shadow DOM.The custom element allows developers to define their HTML tags, while Shadow Dom provides a mechanism for packaging HTML and CSS.
2. Data binding: The Polymer framework provides a powerful data binding mechanism, which can associate data with the interface element, so that the changes in the data can be automatically reflected on the interface and realize the real -time synchronization of the interface and the data.
3. Response design: The Polymer framework supports the response design, which can automatically adjust the interface in different layouts according to the screen size and direction of the device.
4. Componentization development: Polymer framework encourages developers to split the application into multiple components that are available. Each component contains its own HTML template, CSS style, and JavaScript code, making the development process more modular and maintainableEssence
5. Construction tool: The Polymer framework provides a series of construction tools, such as Polymer Cli and Polymer Build, which can help developers pack, compress and optimize code, improve the performance and loading speed of the application.
Below is an example code for the Polymer framework to show its implementation principle:
html
<!-Define a custom element->
<dom-module id="my-element">
<template>
<style>
.highlight {
color: red;
}
</style>
<div class$="[[getHighlightClass()]]">Hello, [[name]]!</div>
<button on-click="changeName">Change Name</button>
</template>
<script>
class MyElement extends Polymer.Element {
static get is() { return 'my-element'; }
static get properties() {
return {
name: {
type: String,
value: 'Polymer',
},
};
}
getHighlightClass() {
return this.name.length > 5 ? 'highlight' : '';
}
changeName() {
this.name = 'Polymer Framework';
}
}
customElements.define(MyElement.is, MyElement);
</script>
</dom-module>
<!-Use custom elements->
<my-element></my-element>
In the above code, we define a custom element `my-element`, which contains a display text and a button.`name` is a attribute, used to record the name to be displayed, and the default value is` Polymer`.`GethlightClass` method is used to return a CSS class name according to the length of the` name`. If the length of the `name` is greater than 5, add the name of the` Highlight` to achieve the highlights of the text.The `Changename` method is used to change the value of the` name` attribute.Finally, the custom element is registered into the browser through the `CustomElements.define` method. This element can be used in the page through the page in the page.
In addition to the above code, the Polymer framework also involves some related configuration files and tools, such as `Polymer.json` files to configure the application options of the application, the Polymer CLI command line tool is used for running, testing, and publishing applications.
In summary, the Polymer framework is a front -end development framework based on the web component standard. It builds an application through packaging, reuse and customized web components.Its implementation principles include web component standards, data binding, response design, component development and construction tools.Through the example code, we can understand the basic usage and functions of the Polymer framework.
