In -depth exploration of Polymer framework in the Java library
In -depth exploration of Polymer framework in the Java library
introduction:
Polymer is an open source JavaScript library based on the web component standard. It provides a lightweight method to build a reclined custom HTML element.The Polymer framework can not only simplify web development, but also make the code more readable, maintained and reused.This article will explore the working principle of the Polymer framework and provide some Java code examples to help readers better understand and apply the Polymer framework.
1. Polymer's basic concept
1.1 Custom element:
Polymer allows developers to create custom HTML elements, which can be used in web pages like conventional HTML elements.Custom elements are usually composed of some HTML templates and JavaScript code to define the structure and behavior of the element.
1.2 Components:
Polymer encapsulates the custom element as a component, and the component is the basic construction block in the Polymer framework.Component is a reusable and independent code module. It has its own internal state and behavior and can interact with other components.Components can consist of one or more custom elements to form a complex application.
1.3 Data binding:
Polymer implements a data binding mechanism that allows developers to bind the attributes of the component with the DOM element.When the attribute value changes, the binding DOM element is automatically updated.Data binding can improve the readability and maintenance of the code, so that developers can handle the status and interaction of components more concisely.
Second, the working principle of the Polymer framework
2.1 Registration component:
Before using the Polymer framework, developers need to register the custom element as a component.By using the Polymer () function provided by the Polymer framework, you can add some additional behaviors and functions to the custom element, such as attributes, methods and event processors.The following is a simple Java code example, which demonstrates how to use the Polymer () function to register a custom element called "My-Element":
@PolymerRegister(tag = "my-element")
public class MyElement extends PolymerElement {
// Define the attributes of the component
@Property
private String name;
// Use @ObServe Note to monitor the attributes
@Observe("name")
protected void nameChanged(String newValue) {
// The logic executed when the attribute changes
}
Use @listen annotation to monitor the event
@Listen("click")
protected void handleClick(Event event) {
// Treat the logic of the click event
}
}
In the above sample code,@Polymerregister annotation is used to specify the label name of the custom element.@Property annotations are used to define the attributes of components, while @ObServe and @listen annotations are used to define monitoring of attributes and events.
2.2 Create example:
When the custom element is registered as a component, the component can be used on the web page.Below is a simple Java code example, demonstrating how to use the just registered custom element in HTML:
html
<!DOCTYPE html>
<html>
<head>
<script src="polymer.js"></script>
<link rel="import" href="my-element.html">
</head>
<body>
<my-element name="Polymer"></my-element>
</body>
</html>
In the above sample code, the HTML file of the custom element is introduced by using the <link> tag, and the <my-Element> tag is used to create an instance of a custom element.By setting the attribute value, the data can be passed to the attributes of the component.
2.3 Life cycle of components:
Polymer components have a life cycle hook function, and developers can perform some specific operations in these functions.Here are some commonly used life cycle hook functions:
-BeforRegister (): Operations performed before component registration.
-registerEd (): The operation performed after the component is successfully registered.
-Created (): The operation performed after the component instance was created.
-ATTACHED (): The operation performed when the component was added to the DOM tree.
-DETACHED (): The operation performed when the component was removed from the DOM tree.
-ATTRIBUTECHANGED (): The operation executed when the component attribute changes.
-Rady (): Operations executed after the component preparation.
3. Summary
The Polymer framework provides a simple and powerful way to build a reusable custom HTML element.By registering components, creating instances, and using the life cycle hook function, developers can use the Polymer framework to quickly develop highly interactive and reused web applications.This article introduces the basic concepts, working principles, and example code of Polymer. It is hoped that readers can understand and apply the Polymer framework more deeply.
