Question

我有一个自动完成文本，我可以使用volley stringrequest从Web服务获取建议。现在的问题是ArrayList没有被清除，因此每次我发出请求时，旧项目都会被添加到列表中。我试过adapter.clear()但它给了我NullPointerException。所以任何帮助清除这一点，以便列表不包含旧项目将非常感激。

＆＃13;

LogCat:

FATAL EXCEPTION: main
Process: com.sam.ubooktoday, PID: 24983
java.lang.NullPointerException
at com.sam.ubooktoday.view.fragments.HomeOptionTwo$1.onResponse(HomeOptionTwo.java:88) 
at com.sam.ubooktoday.view.fragments.HomeOptionTwo$1.onResponse(HomeOptionTwo.java:69) 
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:60)
at com.android.volley.toolbox.StringRequest.deliverResponse(StringRequest.java:30)
at com.android.volley.ExecutorDelivery$ResponseDeliveryRunnable.run(ExecutorDelivery.java:99)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5388)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:655)
at dalvik.system.NativeStart.main(Native Method)

＆＃13;

// if you press 'na' json response is:

[
  "Manicure and Pedicure ",
  "Manicures",
  "Pedicures",
  "Student Specials Under 18 Years",
  "Hand & Foot Care and Repair",
  "Nail Art Design ",
  "Polish Change",
  "Kids Menu under 12 years",
  "Healthy Nail Dip in powder",
  "Nail Enhancement",
  "Full Set",
  "Fill Ins"
]

＆＃13;

public class HomeOptionTwo extends Fragment implements TextWatcher{

    AutoCompleteTextView autoservice;
    ArrayList<String> arrList = new ArrayList<String>();
    ArrayAdapter<String> adapter;

    private static final String SERVICE = "http://example.com/android/services";

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.homeoptiontwo, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        autoservice = (AutoCompleteTextView)view.findViewById(R.id.service);


        autoservice.addTextChangedListener(this);





    }

    private void prepareMyList() {

        StringRequest stringRequest = new StringRequest(Request.Method.POST, SERVICE,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        try {



                            JSONArray jsonarray = new JSONArray(response);
                            for (int i = 0; i < jsonarray.length(); i++) {
                                //Toast.makeText(getActivity(), "services:" + jsonarray.optString(i), Toast.LENGTH_SHORT).show();

                                String strValue = jsonarray.getString(i);


                                arrList.add(strValue);

                            }

                                adapter = new ArrayAdapter<String>(
                                    getActivity(),
                                    android.R.layout.simple_dropdown_item_1line,
                                    arrList);


                            autoservice.setThreshold(1);

                            if(adapter!=null){adapter.clear();}
                            autoservice.setAdapter(adapter);






                        } catch (JSONException e) {
                            // JSON error
                            e.printStackTrace();
                            Toast.makeText(getActivity(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
                        }
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(getActivity(), "VolleyError" + error.toString(), Toast.LENGTH_LONG).show();
            }
        }) {
            @Override
            protected Map<String, String> getParams() {
                Map<String, String> params = new HashMap<String, String>();
                params.put("phrase", autoservice.getText().toString());
                return params;
            }

        };

        RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
        requestQueue.add(stringRequest);
    }


    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        prepareMyList();

    }

    @Override
    public void afterTextChanged(Editable s) {

    }
}

＆＃13;

Answer 1

您不需要清除适配器，因为您每次都要设置新适配器，但需要清除列表，以便从列表中获取和显示新数据。

所以在prepareMyList（）方法中，在try catch方法中首先写下JSONArray之前的行jsonarray = new JSONArray（response）;线。

所以它看起来像，

     arrList = new ArrayList<String>();
     JSONArray jsonarray = new JSONArray(response);

然后检查它是否会解决您的问题。

Answer 2

最近对我说了同样的事情，我的问题是过滤器正在过滤我的结果，因为我的结果没有与键入的文本字符串匹配。也可能是你的情况。

在您的阵列适配器上尝试@Override getFilter()并返回无效的new Filter()。喜欢：

public Filter getFilter() {

            return new Filter() {

                @Override
                protected void publishResults(CharSequence constraint,FilterResults results) {


                }

                @Override
                protected FilterResults performFiltering(CharSequence constraint) {

                    return null;
                }
            };
        }

autocompletetextview不更新

2 个答案: