android - AsyncTask 完成后无法关闭 ProgressDialog

Question

请帮忙，我无法在 AsyncTask 完成后关闭 ProgressDialog。我搜索了答案，但没有找到。当我使用 Thread 而不是 AsyncTask 时，这段代码工作正常。有什么想法吗？

Context appContext;
ProgressDialog pd;

@Override
public void onCreate(Bundle savedInstanceState)
{
   super.onCreate(savedInstanceState);
   appContext=this;
   MyTask myTask=new MyTask(); 
   myTask.execute();
}


class MyTask extends AsyncTask<Void, Void, Void>
{
   @Override
   protected void onPreExecute() 
   {
      pd = ProgressDialog.show(appContext, "Wait..", "Loading data",
                    true, false);
  pd.setCancelable(false);
      super.onPreExecute();
   }

   @Override
   protected Void doInBackground(Void... arg0)
   {
  //something
  return null;
    }

   @Override
   protected void onPostExecute(Void result)
   {
      if (pd!=null)
        pd.dismiss();
  super.onPostExecute(result);
   }
}

Answer 1

   private ProgressDialog progressDialog;   // class variable       

   private void showProgressDialog(String title, String message)
   {
        progressDialog = new ProgressDialog(this);

        progressDialog.setTitle(title); //title

        progressDialog.setMessage(message); // message

        progressDialog.setCancelable(false);

        progressDialog.show();
   }         

onPreExecute()

    protected void onPreExecute()
    {
        showProgressDialog("Please wait...", "Your message");
    }

检查并关闭 onPostExecute() -

    protected void onPostExecute() 
    {
        if(progressDialog != null && progressDialog.isShowing())
        {
            progressDialog.dismiss();
        }
     }