java - 创建自定义覆盖方法问题

Question

我创建了如下所示的类。但 Override 方法没有被调用。有什么我错过的吗？否则我需要添加任何关键字(如 Virtual)来用作覆盖？

MyWebView.java

package com.example.stackoverflow;    

import android.content.Context;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.LinearLayout;

public class MyWebView extends WebView 
{
    WebView localView;
    static Context localcontext;
    A aclass;

    public MyWebView(Context context)
    {
        super(context);     
        localcontext=context;
    }

    public LinearLayout init()
    {
        LinearLayout layout=new LinearLayout(localcontext);
        localView=new WebView(localcontext);
        localView.setWebViewClient(new MyClient());
        aclass=new A();
        layout.addView(localView);
        return layout;
    }

    class MyClient extends WebViewClient
    {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            aclass.startMyMethod();
            return super.shouldOverrideUrlLoading(view, url);
        }
    }

}

A.java

package com.example.stackoverflow;

import android.os.Bundle;
import android.widget.LinearLayout;
import android.app.Activity;

public class A extends Activity 
{

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        MyWebView view=new MyWebView(this);
        LinearLayout layout = view.init();
        view.loadUrl("https://www.google.co.in/");
        setContentView(layout);
     }

    public void startMyMethod() 
    {       
        System.out.println("ParentMethod");
    }
}

B.java(MainActivity)

package com.example.stackoverflow;

import android.os.Bundle;

public class B extends A {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
     }

    @Override
    public void startMyMethod() {
        System.out.println("ChildMethod");
        super.startMyMethod();
    }

}

Note: class B is client side class. others two in jar file. how can i use new B() inside jar file(library source). name B may be changed. If parent method is overridden, then parent content should not be executed

Answer 1

Java没有像virtual这样的关键字，默认情况下所有java非静态方法都是虚拟的。请参阅http://en.wikipedia.org/wiki/Virtual_function#Java .

@Override 注解用于指示编译器您正在重写父类(super class)方法。请参阅here

A a =new A();
a.startMyMethod(); // calls A.startMyMethod()

A b = new B(); // Object reference of type A and Object of B
a.startMyMethod(); // calls B.startMyMethod()