Android -- WebView进度条

requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);//先给Activity注册界面进度条功能    
setContentView(R.layout.main);//布局
setProgressBarIndeterminateVisibility(true);//在需要显示进度条的时候调用这个方法    
setProgressBarIndeterminateVisibility(false);//在不需要显示进度条的时候调用这个方

public class ProgressWebView extends WebView {

    private ProgressBar progressbar;

    public ProgressWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
        progressbar = new ProgressBar(context, null, android.R.attr.progressBarStyleHorizontal);
        progressbar.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, 3, 0, 0));
        addView(progressbar);
        //        setWebViewClient(new WebViewClient(){});
        setWebChromeClient(new WebChromeClient());
    }

    public class WebChromeClient extends android.webkit.WebChromeClient {
        @Override
        public void onProgressChanged(WebView view, int newProgress) {
            if (newProgress == 100) {
                progressbar.setVisibility(GONE);
            } else {
                if (progressbar.getVisibility() == GONE)
                    progressbar.setVisibility(VISIBLE);
                progressbar.setProgress(newProgress);
            }
            super.onProgressChanged(view, newProgress);
        }

    }

    @Override
    protected void onScrollChanged(int l, int t, int oldl, int oldt) {
        LayoutParams lp = (LayoutParams) progressbar.getLayoutParams();
        lp.x = l;
        lp.y = t;
        progressbar.setLayoutParams(lp);
        super.onScrollChanged(l, t, oldl, oldt);
    }
}

public class WebActivity extends BaseActivity {

    private ProgressWebView webview;
    private String url;
    private String name;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_web);

        //  获取参数
        url = getIntent().getStringExtra("url");
        name = getIntent().getStringExtra("name");

        //绑定控件
        webview = (ProgressWebView) findViewById(R.id.webview);

        //设置数据
        titleText.setText(name);
        webview.getSettings().setJavaScriptEnabled(true);
        webview.setDownloadListener(new DownloadListener() {
            @Override
            public void onDownloadStart(String url, String userAgent, String contentDisposition, String mimetype, long contentLength) {
                if (url != null && url.startsWith("http://"))
                    startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse(url)));
            }
        });

        webview.loadUrl(url);
    }
}

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

    <com.yydcdut.webdemo.ui.ProgressWebView
        android:id="@+id/webview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" />

</LinearLayout>