WebViewClient.onPageStarted( ) zwei mal aufgerufen, wenn die Angabe von nicht existierenden URL per WebView.loadURL()

Ich kämpfte mit diesem als gut, aber ich glaube, ich habe um ihn herum gearbeitet. Grundsätzlich setze ich ein flag auf Fehler, um die client-von der Verarbeitung mehr Rückrufe. Das flag wird zurückgesetzt, wenn ich eine Methode aufrufen in der Aktivität zu versuchen die Last wieder. Hier finden Sie einige Beispiel-code aus einer Kernaussage, die ich erstellt https://gist.github.com/museofwater/6373048

public class AsyncMultiplayerSetupActivity extends Activity {

    private static final String TAG = AsyncMultiplayerSetupActivity.class.getName();
    public static final String UTF_8 = "UTF-8";

    private WebView wvSignin;
    private String url = "http://localhost:9000/signin";
    private ProgressDialog progressLoadUrl;
    private SigninWebViewClient webViewClient;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent intent = getIntent();
        registerUser(url);
    }

    private void registerUser(String url) {
        webViewClient = new SigninWebViewClient(getResources().getInteger(R.integer.timeout));
        setContentView(R.layout.setup);
        wvSignin = (WebView)findViewById(R.id.wvSignin);
        wvSignin.getSettings().setJavaScriptEnabled(true);
        wvSignin.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
        wvSignin.setWebViewClient(webViewClient);
        loadUrl(url);
    }

    private void loadUrl(String url) {
        if (!NetworkUtil.checkNetwork(this)) {
            setSigninFailureResult();
        }
        //Show progress
        progressLoadUrl =
                ProgressDialog.show(this, getString(R.string.CONNECTING_TITLE),
                        getString(R.string.CONNECTING_MSG));
        webViewClient.prepareToLoadUrl();
        wvSignin.loadUrl(url);
    }

    private void setSigninFailureResult() {
        setResult(getResources().getInteger(R.integer.RESPONSE_FAILED_CODE));
        finish();
    }

    private void setSigninResult() {    
        setResult(getResources().getInteger(R.integer.RESPONSE_OK_CODE));
    }

    private class SigninWebViewClient extends WebViewClient {
        /**
         * Timeout for page load in seconds
         */
        private int timeout;
        private String urlLoading;

        boolean pageLoaded = false;

        //Flag to instruct the client to ignore callbacks after an error
        boolean hasError = false;

        private Handler timeoutHandler;
        private AlertDialog alertDialog;

        private SigninWebViewClient(int timeout) {
            this.timeout = timeout;
            timeoutHandler = new Handler();
        }

        //Called by activity before requesting load of a url
        private void prepareToLoadUrl() {
           this.hasError = false;
           this.pageLoaded = true;
           this.urlLoading = null;
        }

        @Override
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            if (hasError) {
                return;
            }
            urlLoading = url;
            //timeout has expired if this flag is still set when the message is handled
            pageLoaded = false;
            Runnable run = new Runnable() {
                public void run() {
                    //Do nothing if we already have an error
                    if (hasError) {
                        return;
                    }

                    //Dismiss any current alerts and progress
                    dismissProgress();
                    dismissErrorAlert();
                    if (!pageLoaded) {
                        showTimeoutAlert();
                    }
                }
            };
            timeoutHandler.postDelayed(run, this.timeout*1000);
        }

        @Override
        public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
            //Ignore future callbacks because the page load has failed
            hasError = true;
            dismissProgress();
            showServerErrorAlert();
        }

        @Override
        public void onPageFinished(WebView view, String url) {
            if (hasError) {
                return;
            }
            pageLoaded = true;
            dismissProgress();
            dismissErrorAlert();
            urlLoading = null;

            //Do whatever processing you need to on page load here
         }

        private void showTimeoutAlert() {
            showErrorAlert(R.string.TIMEOUT_TITLE, R.string.TIMEOUT_MSG);
        }

        private void showServerErrorAlert() {
            showErrorAlert(R.string.SERVER_ERROR_TITLE,R.string.SERVER_ERROR_MSG);
        }

        private void showErrorAlert(int titleResource, int messageResource) {
            AlertDialog.Builder builder = new AlertDialog.Builder(AsyncMultiplayerSetupActivity.this);
            //Add the buttons
            builder.setTitle(titleResource)
                    .setMessage(messageResource)
                    .setPositiveButton(R.string.RETRY, new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog, int id) {
                            //Try to load url again
                            loadUrl(urlLoading);
                            dialog.dismiss();
                        }
                    });
            builder.setNegativeButton(R.string.CANCEL, new DialogInterface.OnClickListener() {
                 public void onClick(DialogInterface dialog, int id) {
                     //User cancelled the dialog
                     setSigninFailureResult();
                     dialog.cancel();
                }
            });

            //Create the AlertDialog
            alertDialog = builder.create();
            alertDialog.show();
        }

        private void dismissProgress() {
            if (progressLoadUrl != null && progressLoadUrl.isShowing()) {
                progressLoadUrl.dismiss();
            }
        }

        private void dismissErrorAlert() {
            if (alertDialog != null && alertDialog.isShowing()) {
                alertDialog.dismiss();
            }
        }
    }
}

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