Android WebView前进按钮

我想知道如何像在android的私人浏览器中一样禁用和启用前向菜单按钮.我正在编写一个显示3个webview的应用程序,并且我希望合并android自己的浏览器选项的基本功能.到目前为止一切正常wrt功能.唯一的事情是“ forward”菜单项始终处于启用状态.我也提到过conditoin,因为canGoFwd然后goFwd.问题是,我分别定义了菜单项并分别编写了前进功能,问题是动态更改“前进”按钮的状态

解决方法:

private WebView webView;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.webview);

    webView = (WebView) findViewById(R.id.webView1);
    webView.getSettings().setJavaScriptEnabled(true);
    final Button prevIoUsButton =(Button) findViewById(R.id.prevIoUsButton);

    prevIoUsButton.setonClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // Todo Auto-generated method stub

               if(webView.canGoBack()){
                   webView.goBack();
               }
        }
    });
    final Button forwardButton =(Button) findViewById(R.id.forwardButton);

    forwardButton.setonClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // Todo Auto-generated method stub

               if(webView.canGoForward()){
                   webView.goForward();
               }
        }
    });
    webView.setWebViewClient( new WebViewClient() {



        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            // Todo Auto-generated method stub
            super.onPageStarted(view, url, favicon);
        }

        @Override
        public void onPageFinished( WebView view, String url ) {

            super.onPageFinished(webView, url );

            prevIoUsButton.setEnabled(view.canGoBack());
            forwardButton.setEnabled(view.canGoForward());

        }

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

            super.onReceivedError( webView, errorCode, description, failingUrl );
            Toast.makeText( WebViewActivity.this, description, Toast.LENGTH_LONG );
        }
    } );
    webView.loadUrl("");

webview.xml文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <WebView
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/webView1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

    <Button
        android:id="@+id/prevIoUsButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:enabled="false" 
        android:text="prevIoUs"/>

    <Button
        android:id="@+id/forwardButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_toRightOf="@+id/prevIoUsButton"
        android:text="forward"
        android:enabled="false" />
</RelativeLayout>