Show ProgressDialog, Retrieve Data, and WAIT FOR IT

I'm writing an app that at many points will attempt to retrieve account information from a website. I'd like to write a single function ("getAccount()") to do the following:

1. Show a ProgressDialog
2. Make the call to the website
3. Wait for a response
4. Clear the ProgressDialog
5. Return control to the calling function after the first four steps are done

I'm not having a problem with getting the data from the page; the problem I have is with the whole "show dialog / wait for completion / return control to the calling function" portion. Either the ProgressDialog doesn't show at all, or the function returns to the caller immediately after making the data request from the site, without giving it enough time to retrieve the data.

Any help would be most appreciated.

EDIT: I'm adding a bit of code below for what I have with AsyncTask. Notice that I have the line MsgBox("done") inside grabURL(); this is simply a Toast call. When I run this code, "done" pops up while the HTTP request is still being made. This MsgBox line only exists so I can see if grabURL is properly waiting for GrabURL to finish (which it isn't).

public void grabURL() {
   new GrabURL().execute();
   MsgBox("done");
}

private class GrabURL extends AsyncTask<String, Void, Void> {
   private ProgressDialog Dialog = new ProgressDialog(MyContext);

   protected void onPreExecute() {
       Dialog.setTitle("Retrieving Account");
       Dialog.setMessage("We're retrieving your account information. Please wait...");
       Dialog.show();
   }

   protected Void doInBackground(String... urls) {
       try {
           // 开发者_如何学编程Get account info from the website
           String resp = GetPage(ThePage); // I have this classed out elsewhere
           // Some other code that massages the data
           AccountRetrievalSuccess = true;
       } catch (Exception e) {
           AccountRetrievalSuccess = false;
       }

       return null;
   }

   protected void onPostExecute(Void unused) {
       Dialog.dismiss();
   }

}

The message box done appears because AsyncTask is using a separate thread(s) to run doInBackground. The call to execute does NOT block. You could move message box done to onPostExecute following the call to dismiss. Tip. You may want to call progress.cancel in onPause or you may get unwanted behaviour on orientation change. Finally, if you are retrieving info in doInBackground, consider returning the info in doInBackground. The info will be passed to onPostExecute. So if the info is object MyInfo consider:

private class GrabURL extends AsyncTask<String, Void, MyInfo> {

Can't say for sure without seeing some code but sounds like you are making a asynchronous call to the website when you want to make a synchronous call (which will block and wait for return data) to the website instead.

You want to use an AsyncTask, generate a non-user-cancellable ProgressDialog in the onPreExecute, do your work in doInBackground, and dismiss it in onPostExecute.

Something like this:

public class MyApp extends Activity
{

  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    // blah blah blah

    URL url;
    try
    {
      url = new URL("http://example.com");
      new MyTask().execute(url);
    }
    catch (MalformedURLException e)
    {
    }

  }

  protected void doSomeStuff()
  {
    // stuff to do after the asynctask is done
  }


  protected void throwAWobbly()
  {
    // stuff to do if you didn't get the data
  }

  // inner class to do the data getting off the UI thread,
  // so android doesn't "not responding" kill you
  private class MyTask extends AsyncTask<URL, Void, Boolean>
  {
    private ProgressDialog dialog;
    private boolean gotData = false;

    protected void onPreExecute()
    {
      // create a progress dialog
      dialog = ProgressDialog.show(MyApp.this, "",
                "Doing stuff. Please wait...", false, false);
    }

    protected Boolean doInBackground(URL... urls)
    {
       // get your data in here!
       return gotData;
    }

    protected void onPostExecute(Boolean result)
    {
       // get rid of the progress dialog
       dialog.dismiss();

       if (true == result)
       {
         // got all data!
         doSomeStuff();
       }
       else
       {
         // oops!
         throwAWobbly();
       }
    }
  }

}