ANDROID-为什么未列出项目？

Question

我正在尝试将项目添加到列表视图并设置适配器。但是我不知道怎么了，因为我无法将项目设置为列表->适配器。

主要活动：

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    //Json
    new GetDataTask().execute();

    //Datas
    categoryModelArrayList = new ArrayList<>();
    categoryAdapter = new CategoryAdapter(MainActivity.this, categoryModelArrayList);
    ListView listView = findViewById(R.id.listView);
    listView.setAdapter(categoryAdapter);

    //Drawer
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();
    NavigationView navigationView = findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}

@SuppressLint("StaticFieldLeak")
private class GetDataTask extends AsyncTask<Void, Void, Void> {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();

    }

    @Override
    protected Void doInBackground(Void... params) {
            String url = Constant.baseUrl+"?json=get_category_index";
            StringRequest stringRequest = new StringRequest(url, new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    try {
                        JSONObject jsonObject = new JSONObject(response);
                        JSONArray jsonArray = jsonObject.getJSONArray("categories");
                        for (int i = 0; i < jsonArray.length(); i++) {
                            CategoryModel categoryModel = new CategoryModel();
                            JSONObject jo = jsonArray.getJSONObject(i);
                            String id = jo.getString("id");
                            String title = jo.getString("title");
                            Log.d("Veri", id);
                            categoryModel.setCatID(id);
                            categoryModel.setCatTitle(title);
                            categoryModelArrayList.add(categoryModel);
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                        Log.i("Error", e.getLocalizedMessage());
                    }
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // Anything you want
                }
            });
            RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
            requestQueue.add(stringRequest);
        return null;
    }

    @Override
    protected void onPostExecute(Void aVoid) {
        super.onPostExecute(aVoid);
        if(categoryModelArrayList.size() > 0) {
            categoryAdapter.notifyDataSetChanged();
        } else {
            System.out.println("No data");
        }
    }
}

@Override
public void onBackPressed() {
    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();

    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_camera) {
        // Handle the camera action
    } else if (id == R.id.nav_gallery) {

    } else if (id == R.id.nav_slideshow) {

    } else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    } else if (id == R.id.nav_send) {

    }

    DrawerLayout drawer = findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

@Override
protected void onResume(){
    super.onResume();
}

@Override
protected void onPause(){
    super.onPause();
}

@Override
protected void onDestroy(){
    super.onDestroy();
}

我正在使用您看到的代码提取数据。来自服务器的数据成功发送。我正在尝试将此数据发送到model，然后发送到adapter。但是以某种方式不会发生。我确定我忘记了一些东西，但是我不知道什么:)有什么想法吗？