4.初学ExtJs——类的继承

墨蓝 2022-08-12 02:00 138阅读 0赞

<html>
    <head>
    <meta http-equiv="Content-Type" content ="text/html";charset="utf-8" />
    <title>ExtJS</title>
    <link rel="stylesheet" type="text/css" href="resources/css/ext-all.css" />
    <script type="text/javascript" src="ext-all.js"></script>
    <script type="text/javascript" src="ext-lang-zh_CN.js" charset="utf-8"></script>
    
    <script>
    Ext.define("Person", {
        Name: '',
        Age: 0,
        Say: function (msg) {
            Ext.Msg.alert(this.Name + " Says:", msg);
        },
        constructor: function (name, age) {
            this.Name = name;
            this.Age = age;
        }
    });
    
    Ext.define("Developer", {
        extend: 'Person',
        Coding: function (code) {
            Ext.Msg.alert(this.Name + " 正在编码", code);
        },
        constructor: function(){
            this.callParent(arguments);
        }
    });
    
    Ext.onReady(function(){
    	var Bill = new Developer("Bill", 26);
    	Bill.Coding("int num1 = 0; ");
    });
    </script>
    
    </head>
    <body>
    </body>
    </html>

运行结果：

![Center][]

从代码中可看出，ExtJS 使用 extend来实现继承。我们为Developer 类添加了Coding 方法，这是我们对Person类进行的扩展。在构造函数中，通过调用this.callParent 方法，实现对属性的初始化。需要说明的是，如果此处只调用了父类的构造方法，则可以省略掉，ExtJS 会自动为我们调用父类的构造函数。所以我们此处的代码可以进行简化：

Ext.define("Developer", {
        extend: 'Person',
        Coding: function (code) {
            Ext.Msg.alert(this.Name + " 正在编码", code);
        }
    });

参考自： [http://www.cnblogs.com/youring2/p/3274135.html][http_www.cnblogs.com_youring2_p_3274135.html]

[Center]: /images/20220810/386f4b432d864324896f924008b5b497.png
[http_www.cnblogs.com_youring2_p_3274135.html]: http://www.cnblogs.com/youring2/p/3274135.html