java - 旋转器事件后 Json Listview 不会刷新

Question

我的问题是我的 ListView 上有一个产品列表，当我从微调器中选择一个值时，我保存它并发送它以从我的 mysql 数据库中检索不同的值，我遇到的问题是我的 ListView 不会在我的微调器上执行 onclick 事件后更新，我做错了什么？我不知道我是否能够正确解释我想说的话，谢谢您的帮助

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
            {
                public void onItemSelected (AdapterView < ? > parent, View view,int pos, long id)
                {
                    filtracat();
                }


private void filtracat() {
    cat = spinner.getSelectedItemPosition()+1;
     valor = String.valueOf(cat);
    Toast.makeText(getApplicationContext(),valor,Toast.LENGTH_SHORT).show();
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(JSON_CAT, new Response.Listener<JSONArray>() {
        @Override
        public void onResponse(JSONArray response) {
            hideDialog();
            //parsing json
            for (int i = 0; i < response.length(); i++) {
                try {
                    JSONObject obj = response.getJSONObject(i);
                    Anuncios item = new Anuncios();
                    item.setKey(obj.getString("key"));
                    item.setTitulo(obj.getString("titulo"));
                    item.setImageID(obj.getString("imageID"));
                    item.setModelo(obj.getString("modelo"));
                    item.setPreco(obj.getString("preco"));
                    //gonna set category here
                    //    item.setCategoria(obj.getString("categoria"));
                    //add to array
                    array2.add(item);
                } catch (JSONException ex) {
                    ex.printStackTrace();
                }
            }
            adapter.notifyDataSetChanged();
        }
    }, new ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

        }
    }) {
        @Override
        protected Map<String, String> getParams() {
            Map<String, String> params = new HashMap<String, String>();

            params.put("valor", valor);
            return params;
        }


    };
AppController.getmInstance().addToRequesQueue(jsonArrayRequest);
}

我的 ListView 的原始数据来自

 private void sendRequest() {
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(JSON_URL, new Response.Listener<JSONArray>() {
        @Override
        public void onResponse(JSONArray response) {
            hideDialog();
            //parsing json
            for (int i = 0; i < response.length(); i++) {
                try {
                    JSONObject obj = response.getJSONObject(i);
                    Anuncios item = new Anuncios();
                    item.setKey(obj.getString("key"));
                    item.setTitulo(obj.getString("titulo"));
                    item.setImageID(obj.getString("imageID"));
                    item.setModelo(obj.getString("modelo"));
                    item.setPreco(obj.getString("preco"));
                    //gonna set category here
                //    item.setCategoria(obj.getString("categoria"));
                    //add to array
                    array.add(item);
                } catch (JSONException ex) {
                    ex.printStackTrace();
                }
            }
            adapter.notifyDataSetChanged();
        }
    }, new ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

        }
    });
    AppController.getmInstance().addToRequesQueue(jsonArrayRequest);
}

我应该使用相同的数组来更新数据吗？

Answer 1

你可以试试

1. 创建两个对象

         ArrayList<MobileKeyModel> dropDownModels = new ArrayList<MobileKeyModel>();
         ArrayList<Object> addList = new ArrayList<Object>();
   

2. 您可以从数据库获取响应

      private void filtracat() {
        StringRequest stringRequest = new StringRequest(Request.Method.POST, JSON_URL,
           new Response.Listener<String>() {
               @Override
               public void onResponse(String response) {
   
                   try {
                       JSONObject jsonObject = new JSONObject(response);
                       JSONArray loginNodes = jsonObject.getJSONArray("parentnodesList");
                       for (int i = 0; i < loginNodes.length(); i++) {
                           JSONObject jo = loginNodes.getJSONObject(i);
                           String key = jo.getString("key");
                           String titulo = jo.getString("titulo");
                           addList.add(key);
                           addList.add(titulo);
                       }
   
                       pupulateDropDownList();
                   } catch (JSONException e) {
                       e.printStackTrace();
                   }
               }
           },
           new Response.ErrorListener() {
               @Override
               public void onErrorResponse(VolleyError error) {
   
                   try {
                       //Respose Error
   
                   } catch (Exception e) {
   
   
                   }
               }
           }) {
       @Override
       protected Map<String, String> getParams() {
           Map<String, String> params = new HashMap<>();
           return params;
       }
   
   };
   
   
     RequestQueue requestQueue = Volley.newRequestQueue(this);
     requestQueue.add(stringRequest);
   }
   

3. 将值填充到 ListView

   无效 pupulateDropDownList() {

   if (addList != null) {
       for (Iterator<Object> i = addList.iterator(); i.hasNext(); ) {
           MobileKeyModel menuModel = new MobileKeyModel(i.next().toString(), i.next().toString());
           dropDownModels.add(menuModel);
   
       }
   
       ArrayAdapter adapter = new ArrayAdapter(this, R.layout.spinner_text, dropDownModels);
       adapter.setDropDownViewResource(R.layout.simple_spinner_dropdown);
       listView.setAdapter(adapter);
   
      }
   }
   

4. 模型也在这里

   公共(public)类 MobileKeyModel {

   public String key = "";
   public String titulo = "";
   
   public MobileKeyModel(String key, String titulo) {
       this.key = key;
       this.titulo = titulo;
   }
   
   public String getKey() {
       return key;
   }
   
   public void setKey(String key) {
       this.key = key;
   }
   
   public String getTitulo() {
       return titulo;
   }
   
   public void setTitulo(String titulo) {
       this.titulo = titulo;
   }
   

   }

5. 注意您的 json 必须类似于

       {"parentnodesList":[{"key":"your key value here","titulo":"Your title"}]}