Question

我有一个全局变量： List<String> cheifComplaintList = new ArrayList<>();

和方法：fetchCheifComplaints()

，该方法描述为：

private void fetchCheifComplaints() {
    JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(Request.Method.GET,
            endpoints.ENDPOINT_GET_CHEIF_COMPLAINTS,
            null,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {

                    if (BuildConfig.DEBUG) Log.d(TAG, "onResponseCheifComplaints: " + response);

                    try {
                        JSONArray jsonArray = response.getJSONArray("complaints");

                        for (int i = 1; i < jsonArray.length(); i++) {
                            if (BuildConfig.DEBUG) Log.d(TAG, "List: " + jsonArray.getString(i));
                            cheifComplaintList.add(jsonArray.getString(i));
                        }

                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Log.e(TAG, "onErrorResponseCheifComplaints: ", error);
        }
    })

但是我总是得到cheifComplaintList = null。但是，当我将值设置为cheifComplaintList.add("Some value");时，它们会起作用。有人可以帮忙吗？谢谢我前进。

Json的回复是：

onResponseCheifComplaints: {"complaints":[""," Bad breath"," Bleeding gum","Senstivity"," Tooth ache","Wants to clean the teeth"]}

Answer 1

您可能会收到IndexOutOfBoundsException，因为您试图将数据插入ArrayList的位置为1 index而不是0 index

请参见以下代码，并在int i=0;中输入for loop

 try {
                    JSONArray jsonArray = response.getJSONArray("complaints");

                    for (int i = 0; i < jsonArray.length(); i++) {
                        if (BuildConfig.DEBUG) Log.d(TAG, "List: " + jsonArray.getString(i));
                        cheifComplaintList.add(jsonArray.getString(i));
                    }

                } catch (JSONException e) {
                    e.printStackTrace();
                }catch (ArrayIndexOutOfBoundsException e) {
        e.printStackTrace();
    }

希望这会有所帮助

List <string>始终提供空值，直到对数据进行硬编码

1 个答案: