进度对话框在 android studio 中不起作用

Question

我想在我的应用程序中显示进度对话框，直到它加载 URL 并显示它。但它没有显示进度对话框。请帮我。  setContentView(R.layout.activity_main);    mywb = (WebView) findViewById(R.id.webView);    ProgressDialog progressDialog = new ProgressDialog(this);    progressDialog.setTitle("The Book Street");    progressDialog.setMessage("Loading");    progressDialog.setProgressStyle(progressDialog.STYLE_SPINNER);    progressDialog.show();    progressDialog.setCancelable(false);    WebSettings webSettings = mywb.getSettings();    webSettings.setJavaScriptEnabled(true);    mywb.loadUrl("http://www.thebookstreet.com");    progressDialog.dismiss();    mywb.setWebViewClient(new WebViewClient());