refreshScreen

public void refreshScreen_SimpleWay() {
Call<List<Section>> call = restClient.getService().getSectionsByCourseId(_Course_Id);
                call.enqueue(new Callback<List<Section>>() {
                                 @Override
                                 public void onResponse(Call<List<Section>> call, Response<List<Section>> response) {
                                     final ListView lv = (ListView) findViewById(R.id.listView);


                                     final ArrayList<HashMap<String, String>> sectionList = new ArrayList<HashMap<String, String>>();

                                     for (int i = 0; i < response.body().size(); i++) {
                                         HashMap<String, String> section = new HashMap<String, String>();

                                         section.put("id", String.valueOf(response.body().get(i).getId()));
                                         section.put("name", String.valueOf(response.body().get(i).getName()));

                                         sectionList.add(section);
                                     }

                                     final ListAdapter adapter = new SimpleAdapter(CourseManagerActivity.this, sectionList, R.layout.view_user_entry,
                                             new String[]{"id", "name"}, new int[]{R.id.user_Id, R.id.user_name});

                                     lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
                                         @Override
                                         public boolean onItemLongClick(AdapterView<?> parent, final View view, int position, long id) {

                                             final TextView tvName = view.findViewById(R.id.user_name);
                                             TextView tvId = view.findViewById(R.id.user_Id);
                                             _Course_Id = tvId.getText().toString();

                                             AlertDialog.Builder ad;
                                             String title = "Вы действительно хотите удалить '" + tvName.getText() + "'?";
                                             String message = "Удалить?";
                                             String button1String = "Да";
                                             String button2String = "Нет";

                                             ad = new AlertDialog.Builder(CourseManagerActivity.this);
                                             ad.setMessage(title); // сообщение
                                             ad.setPositiveButton(button1String, new DialogInterface.OnClickListener() {
                                                 public void onClick(DialogInterface dialog, int arg1) {

                                                     System.out.println("_Course_Id:::: " + _Course_Id);
                                                     Call<Void> call = restClient.getService().deleteSectionAndChildrenById(_Course_Id);
                                                     call.enqueue(new Callback<Void>() {
                                                         @Override
                                                         public void onResponse(@NonNull Call<Void> call, @NonNull Response<Void> response) {
                                                             if (response.code() == 200) {
                                                                 Toast.makeText(CourseManagerActivity.this, tvName.getText() + " успешно удален!",
                                                                         Toast.LENGTH_LONG).show();

                                                                 refreshScreen_SimpleWay();
}
                                                             else {
                                                                 Toast.makeText(CourseManagerActivity.this, "Error: Not Deleted" + response.errorBody(), Toast.LENGTH_LONG).show();
                                                             }
                                                         }

                                                         @Override
                                                         public void onFailure(@NonNull Call<Void> call, @NonNull Throwable t) {
                                                             Toast.makeText(CourseManagerActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();
                                                         }
                                                     });


                                                 }
                                             });
                                             ad.setNegativeButton(button2String, new DialogInterface.OnClickListener() {
                                                 public void onClick(DialogInterface dialog, int arg1) {
                                                     Toast.makeText(CourseManagerActivity.this, "Отмена", Toast.LENGTH_LONG).show();
                                                 }
                                             });
                                             ad.setCancelable(true);
                                             ad.setOnCancelListener(new DialogInterface.OnCancelListener() {
                                                 public void onCancel(DialogInterface dialog) {
                                                     Toast.makeText(CourseManagerActivity.this, "Отмена", Toast.LENGTH_LONG).show();
                                                 }
                                             });
                                             ad.show();

                                             return true;
                                         }
                                     });

                                     lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                                         @Override
                                         public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                                             tvSection_Id = (TextView) view.findViewById(R.id.user_Id);
                                             String sectionId = tvSection_Id.getText().toString();

                                             section_name = (TextView) view.findViewById(R.id.user_name);
                                             String sectionName = section_name.getText().toString();

                                             Intent objIndent = new Intent(CourseManagerActivity.this, SectionManagerActivity.class);
                                             objIndent.putExtra("section_Id", sectionId);
                                             objIndent.putExtra("section_title", sectionName);
                                             startActivity(objIndent);
                                         }
                                     });


                                     lv.setAdapter(adapter);

                                 }

                                 @Override
                                 public void onFailure(@NonNull Call<List<Section>> call, @NonNull Throwable t) {
                                     Toast.makeText(CourseManagerActivity.this, t.getMessage(), Toast.LENGTH_LONG).show();

                                 }
                             }
                );
}