Então, galera. Estou com um problema, Estou criando uma aplicação e, enquanto a webview é carregada, aparece um ProgressBar carregando antes do conteudo, veja meu codigo. O problema é que, ao iniciar o app, Existe uma activity branca no lugar do webview w o ProgressBar não aparece. Segue o código.
Minha ACTIVITY:
    <FrameLayout
            android:id="@+id/framelayout"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1">
        <WebView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/webView"
            android:layout_alignParentBottom="true"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:layout_alignParentTop="true"
            android:layout_alignParentRight="true"
            android:layout_alignParentEnd="true"
            android:visibility="invisible"/>
        <ProgressBar
            android:id="@+id/progress"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:visibility="invisible"/>
    </FrameLayout>
    </RelativeLayout>
AGORA MINHA CLASSE:
`  // CODIGO DO WEB VIEW
        final WebView myWebView = (WebView) findViewById(R.id.webView);
        myWebView.loadUrl("http://www.idestudos.com.br");
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setSupportZoom(true);
        webSettings.setBuiltInZoomControls(true);
        myWebView.setWebViewClient(new MyBrowser());
        myWebView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return false;
            }
        });
        myWebView.setWebViewClient(new WebViewClient(){
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon){
                ProgressBar pb = (ProgressBar) findViewById(R.id.progress);
                pb.setVisibility(View.VISIBLE);
            }
            public void onPageFinished(WebView view, String url){
                ProgressBar pb = (ProgressBar) findViewById(R.id.progress);
                pb.setVisibility(View.INVISIBLE);
                myWebView.setVisibility(View.VISIBLE);
            }
        });
    }`