Question

我正在尝试使用Asynctask首先检查网站是否可访问，然后打开它。问题是在网站完全加载之前关闭了进度对话框。

public class MainActivity extends Activity {


    private final static String TAG = "MusicFXActivityBrowser";
    /** Called when the activity is first created. */
    @Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
}

public void readWebpage(View v){

     final Intent intent = getIntent();
     final String urlString = intent.getDataString();
     try {
         final WebView webView = new WebView(this);
         final URL url = new URL("http://india-aviation.in/users/userregister/Registration.html");
         new LoadURLTask(webView).execute(url);
     } catch (final MalformedURLException e) {
         Log.e(TAG, "MalformedURLException " + urlString);
     }

}


/**
 * ASync Task that checks if the site is reachable and then loads the URL.
 */
private class LoadURLTask extends AsyncTask<URL, Void, Boolean> {
    final WebView mWebView;
    String mURLString;
    // Experiment STARTS ///////////////////////////////////////////////////////////////////////////////////////////
    ProgressDialog dialog = ProgressDialog.show(MainActivity.this, "", "Please Wait...");

 // Experiment ENDS ///////////////////////////////////////////////////////////////////////////////////////////
    public LoadURLTask(final WebView webView) {
        mWebView = webView;
    }
    /*
     * (non-Javadoc)
     *
     * @see android.os.AsyncTask#doInBackground(Params[])
     */
    @Override
    protected Boolean doInBackground(final URL... urls) {
        final URL url = urls[0];
        mURLString = url.toString();
        boolean isSiteReachable = false;
        final HttpURLConnection httpURLConnection;
        try {
            httpURLConnection = (HttpURLConnection) url.openConnection();
            final int response = httpURLConnection.getResponseCode();
            if (response == HttpURLConnection.HTTP_OK) {
                isSiteReachable = true;
            }
        } catch (final IOException e) {
            Log.e(TAG, "Error connecting to " + mURLString);
        }
        return isSiteReachable;
    }
    /*
     * (non-Javadoc)
     *
     * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
     */
    @Override
    protected void onPostExecute(final Boolean isReachable) {
        if (isReachable) {
            dialog.dismiss();
            setContentView(mWebView);
            mWebView.loadUrl(mURLString);
        } else {
            createAndShowNetworkDialog();
        }
    }
}
/**
 * Shows the network dialog alerting the user that the net is down.
 */
private void createAndShowNetworkDialog() {
    new AlertDialog.Builder(this).setTitle(R.string.browser_error_dialog_title)
            .setMessage(R.string.browser_error_dialog_text)
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(final DialogInterface dialog, final int which) {
                    finish();
                }
            }).show();
}

}

Answer 1

在加载网站之前，对话框正在关闭，因为您在3.xml

之前执行了

UPDATE TableB
SET recordOwner = (SELECT TOP(1) [name] 
                   FROM TableC
                   ORDER BY NEWID())
WHERE recordOwner IS NULL

dismiss()

我建议备用方式您可以先显示网站，当网站在屏幕上启动时，等待2秒钟然后关闭对话框。如果网站启动延迟且您的应用程序 UI将提供正确的行为

，此方法不会失败

在加载URL之前关闭Asynctask

1 个答案: