webview加载页面及前进、后退、刷新操作

import android.app.Activity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.webkit.WebChromeClient;import android.webkit.WebView;import android.webkit.WebViewClient;public class MainActivity extends Activity {private WebView wv2;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);wv2 = (WebView) findViewById(R.id.container);wv2.getSettings().setBuiltInZoomControls(true);wv2.getSettings().setJavaScriptEnabled(true);wv2.setWebViewClient(new WebViewClient());wv2.setWebChromeClient(new WebChromeClient() {public void onProgressChanged(WebView view, int newProgress) {setProgress(newProgress * 100);if (newProgress == 100) {//隐藏进度提示}}});wv2.loadUrl("http://www.baidu.com");}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.activity_main, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {// TODO Auto-generated method stubswitch (item.getItemId()) {case R.id.backward:wv2.goBack();break;case R.id.forward:wv2.goForward();break;case R.id.refresh:wv2.reload();break;default:break;}return true;}}