无法刷新 Spinner 所选项目的 ListView 以从 url 获取新数据

Question

1. 我无法刷新微调器项目选择的列表视图。
2. 我想根据 spinner 的 items 值构建新的 url 以获取新的 json 数据并转换为 listview。
3. 您还可以帮助我告诉我如何创建一种方法来传递新的 url 以获取新数据。

4. 主要问题与标题相同 您的每一个帮助将不胜感激。

   @覆盖 public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { // 膨胀这个片段的布局 View view = inflater.inflate(R.layout.fragment1, container, false);

   String [] array_values = {"All "," 5"," 4"," 3"," 2"," 1"};
   final Spinner spinner = view.findViewById(R.id.spinner);
   
   final ArrayAdapter<String> spinner_adapter = new ArrayAdapter<>(this.getActivity(), android.R.layout.simple_spinner_item, array_values);
   spinner_adapter.setDropDownViewResource(android.R.layout.simple_dropdown_item_1line);
   spinner.setAdapter(spinner_adapter);
   
   final String spinnerValue = spinner.getSelectedItem().toString();
   url = "http://website.com/demo.php?pswd=kvpswd";
   
   listView = (ListView) view.findViewById(R.id.demo_list_view);
   adapter = new CustomListAdapter(this.getActivity(), List);
   listView.setAdapter(adapter);
   
   spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
       public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {
         //  listView.setAdapter(null);
         String spinnerValue = spinner.getSelectedItem().toString();
           url = "http://website.com/demo.php?pswd="+spinnerValue;
           adapter.notifyDataSetChanged();
       }
       public void onNothingSelected(AdapterView<?> parent) {
   
       }
   });
   
   // Creating volley request obj
   JsonArrayRequest Requset = new JsonArrayRequest(url,
           new Response.Listener<JSONArray>() {
               @Override
               public void onResponse(JSONArray response) {
                   Log.d(TAG, response.toString());
                   hidePDialog();
   
                   // Parsing json
                   for (int i = 0; i < response.length(); i++) {
                       try {
   
                           JSONObject obj = response.getJSONObject(i);
   
                           DataFetcher datafetcher = new DataFetcher();
   
                           datafetcher.set1(obj.getString("item1"));
                           datafetcher.set2(obj.getString("item2"));
                           datafetcher.set3(obj.getString("item3"));
                           datafetcher.set4(obj.getString("item4"));
                           datafetcher.set5(obj.getString("item5"));
                           datafetcher.set6(obj.getString("item6"));
                           datafetcher.set7(obj.getString("item7"));
                           datafetcher.set8(obj.getString("item8"));
   
                           // adding list to list array
                           List.add(datafetcher);
   
                       } catch (JSONException e) {
                           e.printStackTrace();
                       }
   
                   }
   
                   // notifying list adapter about data changes
                   // so that it renders the list view with updated data
                   adapter.notifyDataSetChanged();
               }
           }, new Response.ErrorListener() {
       @Override
       public void onErrorResponse(VolleyError error) {
           VolleyLog.d(TAG, "Error: " + error.getMessage());
           hidePDialog();
   
       }
   });
   

   }

Answer 1

为 api 调用和传递 url 和设置数据到列表视图的方法。 下面的方法进入微调器选择时间。

 private void callApiData(String url){
    // Creating volley request obj
    JsonArrayRequest Requset = new JsonArrayRequest(url,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    Log.d(TAG, response.toString());
                    hidePDialog();

                    // Parsing json
                    for (int i = 0; i < response.length(); i++) {
                        try {

                            JSONObject obj = response.getJSONObject(i);

                            DataFetcher datafetcher = new DataFetcher();

                            datafetcher.set1(obj.getString("item1"));
                            datafetcher.set2(obj.getString("item2"));
                            datafetcher.set3(obj.getString("item3"));
                            datafetcher.set4(obj.getString("item4"));
                            datafetcher.set5(obj.getString("item5"));
                            datafetcher.set6(obj.getString("item6"));
                            datafetcher.set7(obj.getString("item7"));
                            datafetcher.set8(obj.getString("item8"));

                            // adding list to list array
                            List.add(datafetcher);
                            setAdapter();
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }

                    }

                    // notifying list adapter about data changes
                    // so that it renders the list view with updated data
                    adapter.notifyDataSetChanged();
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d(TAG, "Error: " + error.getMessage());
            hidePDialog();

        }
    });
}

并且还为适配器设置另一种方法。

  private void setAdapter(){
    if(adpter==null){
        adapter = new CustomListAdapter(this.getActivity(), List);
        listView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
    }
    else{
        adapter.notifyDataSetChanged();
    }
}