android - 在 webview 中添加进度对话框

Question

当页面在 webview 中加载时，我一直在尝试将进度对话框合并到我的应用程序中，因此不仅仅是空白屏幕。我知道这个问题随处可见，但我似乎无法找出对我有用的任何东西。我是编程和使用 android 的新手，所以任何信息都会有所帮助。以下是我目前拥有的代码。使用 onPageStarted 我收到 Bitmap 的编译错误，我不确定问题出在哪里。谢谢。

public class Grades extends Activity{

@Override
protected void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);  


    //requesting system settings

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().requestFeature( Window.FEATURE_PROGRESS);
     WebView webview = new WebView(this);

     //web settings

    WebSettings webSettings = webview.getSettings();
        webSettings.setJavaScriptEnabled(true); 
        webSettings.setDisplayZoomControls(true);
        webSettings.setBuiltInZoomControls(true);


     setContentView(webview);

    //loads webpages in webview instead of launching browser

     webview.setWebViewClient(new WebViewClient() {
            ProgressDialog prDialog;
            @Override
            public void onPageStarted(WebView view, String url, Bitmap favicon) {
                prDialog = ProgressDialog.show(Grades.this, null, "loading, please wait...");
                super.onPageStarted(view, url, favicon);
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                prDialog.dismiss();
                super.onPageFinished(view, url);
            }
        });

   //loading webpage
     webview.loadUrl("page__link");
}

Answer 1

检查这段代码，

    final ProgressDialog pd = ProgressDialog.show(OnlinePaymentActivity.this, "", "Please wait, your transaction is being processed...", true);
            
    WebView mWebview  = (WebView)findViewById(R.id.webView1);
    mWebview.getSettings().setJavaScriptEnabled(true); // enable javascript
    mWebview.getSettings().setLoadWithOverviewMode(true);
    mWebview.getSettings().setUseWideViewPort(true);
    mWebview.getSettings().setBuiltInZoomControls(true);

    mWebview.setWebViewClient(new WebViewClient() {

        @Override
        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
            Toast.makeText(activity, description, Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
            pd.show();
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            pd.dismiss();
            String webUrl = mWebview.getUrl();
        }

    });

    mWebview .loadUrl("www.google.com");