安卓加载网页

package com.example.webview; 
 
import android.os.Bundle; 
import android.annotation.SuppressLint; 
import android.app.Activity; 
import android.view.KeyEvent; 
import android.view.Menu; 
import android.webkit.WebSettings; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 
 
 
public class MainActivity extends Activity 
{ 
 
    private WebView webview;   
    @SuppressLint("SetJavaScriptEnabled") 
    @Override 
    protected void onCreate(Bundle savedInstanceState) 
    { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.activity_main); 
        webview = (WebView) findViewById(R.id.webview); 
        WebSettings webSettings = webview.getSettings(); 
        //设置WebView属性，能够执行Javascript脚本   
        webSettings.setJavaScriptEnabled(true);   
        //设置可以访问文件 
        webSettings.setAllowFileAccess(true); 
         //设置支持缩放 
        webSettings.setBuiltInZoomControls(true); 
        //加载需要显示的网页   
        webview.loadUrl("http://www.baidu.com");   
        //设置Web视图   
        webview.setWebViewClient(new webViewClient ());   
         
    } 
      
 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) 
    { 
        // Inflate the menu; this adds items to the action bar if it is present. 
        getMenuInflater().inflate(R.menu.main, menu); 
        return true; 
    } 
     
    @Override  
    //设置回退   
    //覆盖Activity类的onKeyDown(int keyCoder,KeyEvent event)方法   
    public boolean onKeyDown(int keyCode, KeyEvent event) {   
        if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) {   
            webview.goBack(); //goBack()表示返回WebView的上一页面   
            return true;   
        }   
        finish();//结束退出程序 
        return false;   
    }   
       
    //Web视图   
    private class webViewClient extends WebViewClient {   
        public boolean shouldOverrideUrlLoading(WebView view, String url) {   
            view.loadUrl(url);   
            return true;   
        }   
    }   
 
} 


xml 代码
<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
    android:orientation="vertical"  
    android:layout_width="fill_parent"  
    android:layout_height="fill_parent"  
    >     
    <WebView    
        android:id="@+id/webview"  
        android:layout_width="fill_parent"  
        android:layout_height="fill_parent"  
        />  
</LinearLayout>