如何给webview页面自定义404页面

//示例地图类

package com.can2do.doimobile.news;



import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.webkit.WebView;

import android.webkit.WebViewClient;

import android.widget.TextView;



import com.can2do.doimobile.R;

import com.can2do.doimobile.base.BaseUiWeb;

import com.can2do.doimobile.base.C;



public class UiNewsOne extends BaseUiWeb {

    

    private String tag = null;

    private WebView mWebViewMap;

    

    @Override

    public void onStart() {

        super.onStart();

        

        setContentView(R.layout.ui_news_one);

        

        Bundle params = this.getIntent().getExtras();

        tag = params.getString("tag");

        

        TextView titleText = (TextView) this

                .findViewById(R.id.main_top_title1);

        titleText.setText(tag);

                

        mWebViewMap = (WebView) findViewById(R.id.web_news_one);

        mWebViewMap.getSettings().setJavaScriptEnabled(true);

        mWebViewMap.setWebViewClient(new WebViewClient(){

        });

        mWebViewMap.setWebViewClient(new WebViewClient() {

             public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)

             {

                 view.stopLoading();

                 view.clearView();

                 Message msg=handler.obtainMessage();//发送通知，加入线程

                 msg.what=1;//通知加载自定义404页面

                 handler.sendMessage(msg);//通知发送！

             }

             public boolean shouldOverrideUrlLoading(WebView view, String url)  

             {

                 view.loadUrl(url);

                 return true;

             }

        });

        mWebViewMap.loadUrl(C.news.news1);

        

        this.setWebView(mWebViewMap);

        this.startWebView();

    }

    

     protected Handler handler = new Handler(){

         public void handleMessage(Message message){

             switch (message.what) {

             case 1:

                 mWebViewMap.loadUrl("file:///android_asset/www/404/404.html");

                 break;

             }

         }

     };

         

}