Android AsyncTask中的对话框TextView始终为空

我的AsyncTask中有一个对话框来显示一些图像的加载。对话框中有一个TextView，需要为每个加载的图像更新它，但它总是返回NullPointerException

谁能帮帮我吗

以下是AsyncTask类的代码：

private class addCartRealms extends AsyncTask<Void, Integer, Void> {

        AlertDialog.Builder mBuilder = new AlertDialog.Builder(mainMenu.this);
        AlertDialog dialog;
        View mView = getLayoutInflater().inflate(R.layout.download_loading_dialog, null);
        TextView numberP = findViewById(R.id.loading_number);
        ProgressBar downloadProgress = findViewById(R.id.download_progress_bar);

        @Override
        protected Void doInBackground(Void... params) {

            final OkHttpClient client = new OkHttpClient();
            Realm myRealm = Realm.getDefaultInstance();

            for (int i = 0; i < downloadedCardList.size(); i++) {

                publishProgress(i);

                myRealm.beginTransaction();
                //ADDING CARDS TO REALM
                Card card = myRealm.createObject(Card.class);
                card.setDankness(downloadedCardList.get(i).getDankness());
                card.setExpansion(downloadedCardList.get(i).getExpansion());
                card.setId(downloadedCardList.get(i).getId());
                card.setImgpath(downloadedCardList.get(i).getImgpath());
                card.setLitness(downloadedCardList.get(i).getLitness());
                card.setName(downloadedCardList.get(i).getName());
                card.setRarity(downloadedCardList.get(i).getRarity());
                card.setValue(downloadedCardList.get(i).getValue());

                Request request = new Request.Builder()
                        .url(downloadedCardList.get(i).getImgpath())
                        .build();

                Response response = null;
                Bitmap image = null;
                try {
                    response = client.newCall(request).execute();

                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (response.isSuccessful()) {

                    image = BitmapFactory.decodeStream(response.body().byteStream());
                    ByteArrayOutputStream stream = new ByteArrayOutputStream();
                    image.compress(Bitmap.CompressFormat.PNG, 100, stream);
                    byte[] byteArray = stream.toByteArray();
                    card.setCardImage(byteArray);

                }

                myRealm.commitTransaction();

                //cardImgUrl.add(new cardImagesAndLink(downloadedCardList.get(i).getImgpath(), downloadedCardList.get(i).getId()));

            }


            return null;
        }
        @Override
        protected void onPostExecute(Void result) {

            dialog.dismiss();
            Toast.makeText(mainMenu.this, "Download completato, scaricate " + downloadedCardList.size() + " carte.", Toast.LENGTH_LONG).show();

        }

        @Override
        protected void onPreExecute() {

            mBuilder.setView(mView);
            dialog = mBuilder.create();
            dialog.show();

        }

        @Override
        protected void onProgressUpdate(Integer... values) {

            numberP.setText(values[0] + " / "  + downloadedCardList.size()); // HERE IS THE ERROR

        }



    }

私有类addCartRealms扩展异步任务{
AlertDialog.Builder mBuilder=新建AlertDialog.Builder（主菜单.this）；
警报对话框；
View mView=GetLayoutFlater（）.充气（R.layout.download\u loading\u对话框，空）；
TextView numberP=findviewbyd（R.id.loading\u编号）；
ProgressBar downloadProgress=findviewbyd（R.id.download\u progress\u bar）；
@凌驾
受保护的Void doInBackground（Void…参数）{
最终OkHttpClient客户端=新的OkHttpClient（）；
Realm myRealm=Realm.getDefaultInstance（）；
对于（int i=0；i

错误是这样的：

尝试在空对象引用上调用虚拟方法“void android.widget.TextView.setText（java.lang.CharSequence）”，而不是

TextView numberP = findViewById(R.id.loading_number);

您应该使用对话框的视图

TextView numberP = mView.findViewById(R.id.loading_number);

如果ProgressBar视图包含在对话框布局中，而不是

TextView numberP = findViewById(R.id.loading_number);

您应该使用对话框的视图

TextView numberP = mView.findViewById(R.id.loading_number);

---

如果ProgressBar视图包含在对话框布局中，则可能会对其执行相同的操作。使用以下对话框

findViewById

：

TextView numberP = mView.findViewById(R.id.loading_number);
ProgressBar downloadProgress = mView.findViewById(R.id.download_progress_bar);

---

使用如下对话框

findViewById

：

TextView numberP = mView.findViewById(R.id.loading_number);
ProgressBar downloadProgress = mView.findViewById(R.id.download_progress_bar);