Question

我正在使用JSON HTTP发出AsyncTask请求。我在ProgressDialog中创建了onPreExecute()，我在onPostExecute()中将其解雇了。问题是，diInBackground()中有一个Toast消息，显示J response和ProgressDialog在Toast出现之前被解雇，这意味着onPostExecute()正在在生成Toast之前调用。如何在Toast出现之前解除它？

这是我的代码。

private  class login extends AsyncTask<Void,Void,Void>{
      private ProgressDialog progressDialog;

      @Override
      protected void onPreExecute(){
          super.onPreExecute();
          // Create & Start Progress Dialog
          progressDialog = new ProgressDialog(LoginActivity.this);
          progressDialog.setMessage("Loading...");
          progressDialog.show();
      }
      @Override
      protected Void doInBackground(Void... params) {
          String url = "http://api.openweathermap.org/data/2.5/weather?q=London,uk";
          JsonObjectRequest req = new JsonObjectRequest(url, null,
                  new Response.Listener<JSONObject>() {

                      @Override
                      public void onResponse(JSONObject response) {

                          try {

                                  Toast.makeText(getApplicationContext(),response.toString() , Toast.LENGTH_SHORT).show();

                              }

                          }
                          catch (Exception e){
                              Toast.makeText(getApplicationContext(),"Server error!..",Toast.LENGTH_SHORT).show();

                          }


                      }
                  }, new Response.ErrorListener() {
              @Override
              public void onErrorResponse(VolleyError error) {
                  VolleyLog.e("from on error response Server Error..: ", error.getMessage());

              }
          });

          AppController.getInstance().addToRequestQueue(req);

            return null;
      }
      @Override
      protected void onPostExecute(Void v){
          // Terminate Progress Dialog
          progressDialog.dismiss();
      }
      }

Answer 1

try {

                              Toast.makeText(getApplicationContext(),response.toString() , Toast.LENGTH_SHORT).show();

                          }

                      }
                      catch (Exception e){
                          Toast.makeText(getApplicationContext(),"Server error!..",Toast.LENGTH_SHORT).show();

                      }

这段代码完全错了。 您无法从doInBackground添加Toast。。你需要在解雇dioalog之后移动它

// Terminate Progress Dialog
      progressDialog.dismiss();
//Add your Toast here

Answer 2

无需在异步任务中编写Volley请求。您可以直接执行该任务，因为它内部使用线程。所以一旦你得到了响应或失败，那么你可以自己关闭对话框。我想这会对你有所帮助

 String url = "http://api.openweathermap.org/data/2.5/weather?q=London,uk";
      JsonObjectRequest req = new JsonObjectRequest(url, null,
              new Response.Listener<JSONObject>() {

                  @Override
                  public void onResponse(JSONObject response) {

      if(progressDialog.isShowing){
     progressDialog.cancel();
       }
                      try {

                              Toast.makeText(getApplicationContext(),response.toString() , Toast.LENGTH_SHORT).show();

                          }

                      }
                      catch (Exception e){
                          Toast.makeText(getApplicationContext(),"Server error!..",Toast.LENGTH_SHORT).show();

                      }


                  }
              }, new Response.ErrorListener() {
          @Override
          public void onErrorResponse(VolleyError error) {
              VolleyLog.e("from on error response Server Error..: ", error.getMessage());
  if(progressDialog.isShowing){
 progressDialog.cancel();
   }
          }
      });

      AppController.getInstance().addToRequestQueue(req);

我希望这对你有所帮助而不需要AsyncTask。

Answer 3

您可以使用TimerTask在吐司节目后手动关闭对话框。您可以看到如何使用TimerTask HERE。您正在使用Toast.LENGTH_SHORT，因此吐司将显示2秒钟。

Answer 4

关闭progressdialog里面的响应和错误监听器......不需要关闭post方法

private  class login extends AsyncTask<Void,Void,Void>{
  private ProgressDialog progressDialog;

  @Override
  protected void onPreExecute(){
      super.onPreExecute();
      // Create & Start Progress Dialog
      progressDialog = new ProgressDialog(LoginActivity.this);
      progressDialog.setMessage("Loading...");
      progressDialog.show();
  }
  @Override
  protected Void doInBackground(Void... params) {
      String url = "http://api.openweathermap.org/data/2.5/weather?q=London,uk";
      JsonObjectRequest req = new JsonObjectRequest(url, null,
              new Response.Listener<JSONObject>() {

                  @Override
                  public void onResponse(JSONObject response) {

                      try {

                              Toast.makeText(getApplicationContext(),response.toString() , Toast.LENGTH_SHORT).show();

                          }

                      }
                      catch (Exception e){
                          Toast.makeText(getApplicationContext(),"Server error!..",Toast.LENGTH_SHORT).show();
      progressDialog.dismiss(); add this line

                      }


                  }
              }, new Response.ErrorListener() {
          @Override
          public void onErrorResponse(VolleyError error) {
              VolleyLog.e("from on error response Server Error..: ", error.getMessage());
      progressDialog.dismiss(); add this line

          }
      });

      AppController.getInstance().addToRequestQueue(req);

        return null;
  }
  @Override
  protected void onPostExecute(Void v){
      // Terminate Progress Dialog
      //progressDialog.dismiss(); comment this line
  }
  }

Answer 5

您想要打印吐司消息然后就可以使用了处理程序。

Handler h = new Handler(this.getMainLooper()); h.post(new Runnable() { @Override public void run() { Toast.makeText(getApplicationContext(),response.toString() , Toast.LENGTH_SHORT).show(); //stopProgress } });

从ToyncTask的doInBackground方法出现在Toast之前被解雇的ProgressDialog

5 个答案: