<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

     xmlns:tools="http://schemas.android.com/tools"

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:orientation="vertical" >

     <ProgressBar

         android:id="@+id/progressBarLoading"

         style="?android:attr/progressBarStyleHorizontal"

         android:layout_width="match_parent"

         android:layout_height="3dp" />

     <WebView

         android:id="@+id/webView1"

         android:layout_width="match_parent"

         android:layout_height="match_parent" />

 </LinearLayout>

package com.example.asynchttpclient;

import android.os.Bundle;

import android.app.Activity;

import android.view.KeyEvent;

import android.view.View;

import android.webkit.WebChromeClient;

import android.webkit.WebSettings.ZoomDensity;

import android.webkit.WebView;

import android.webkit.WebViewClient;

import android.widget.ProgressBar;

public class WebActivity extends Activity {

    private ProgressBar mLoadingProgress;

    private WebView webView;

    private String mstrLoginUrl = "http://baidu.com";

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_web);

        webView = (WebView)findViewById(R.id.webView1);

        mLoadingProgress = (ProgressBar)findViewById(R.id.progressBarLoading);

        mLoadingProgress.setMax(100);

        webView.getSettings().setUseWideViewPort(true);

        webView.getSettings().setJavaScriptEnabled(true);

        webView.getSettings().setSupportZoom(true); //设置可以支持缩放

        webView.getSettings().setDefaultZoom(ZoomDensity.FAR);

        webView.loadUrl(mstrLoginUrl);

        // 覆盖WebView默认使用第三方或系统默认浏览器打开网页的行为，使网页用WebView打开

        webView.setWebViewClient(new WebViewClient() {

            @Override

            public boolean shouldOverrideUrlLoading(WebView view, String url) {

                view.loadUrl(url);

                //设置加载进度条

                view.setWebChromeClient(new WebChromeClientProgress());

                return true;

            }

        });

    }

    private class WebChromeClientProgress extends WebChromeClient{

        @Override

        public void onProgressChanged(WebView view, int progress) {

            if (mLoadingProgress != null) {

                mLoadingProgress.setProgress(progress);

                if (progress == 100) mLoadingProgress.setVisibility(View.GONE);

            }

            super.onProgressChanged(view, progress);

        }

    }

    /**

     * 按键响应，在WebView中查看网页时，检查是否有可以前进的历史记录。

     */

    @Override

    public boolean onKeyDown(int keyCode, KeyEvent event)

    {

        // Check if the key event was the Back button and if there's history

        if ((keyCode == KeyEvent.KEYCODE_BACK) && webView.canGoBack())

        {

            // 返回键退回

            webView.goBack();

            return true;

        }

        // If it wasn't the Back key or there's no web page history, bubble up

        // to the default

        // system behavior (probably exit the activity)

        return super.onKeyDown(keyCode, event);

    }

}