没有数据被添加到android中的整数列表中答案

【问题标题】：no data is added to list of integer in android没有数据被添加到android中的整数列表中
【发布时间】：2018-07-30 19:30:55
【问题描述】：

我有来自 web 服务的 json 数据，应该存储在两个列表中，字符串列表和整数列表。用于字符串的那个可以很好地存储数据，但用于整数的那个不能。它提示错误说 java.lang.IndexOutOfBoundsException: Index: 0, Size: 0

这里是完整的代码

 public class Setup extends AppCompatActivity {
Button save;
EditText schoolPK;
String schoolname, classname, cityname, school_id,class_id;
ImageView logout;
GridView grid;
String cityid,classid;
int schoolid;
ArrayList<String> CityName, CityId;
private List<Integer> classID=new ArrayList<Integer>();
private List<String> listschools = new ArrayList<String>();
private List<String> listclasses = new ArrayList<String>();

Spinner schoolspinner;
public static final String MyPREFERENCES = "MyPrefs" ;
public static final String classnames = "classname";
public static final String schoolnames = "schoolname";
public static final String Email = "emailKey";
SharedPreferences sharedpreferences;

String saved_letter;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.setup2);



    CityName=new ArrayList<>();
    CityId = new ArrayList<>();
    //classID = new ArrayList<>();
   // schoolID = new ArrayList<>();

    schoolPK = (EditText) findViewById(R.id.schoolPK);


    final Spinner city = (Spinner) findViewById(R.id.city);
   final Spinner classspinner = (Spinner) findViewById(R.id.classname);
    String URL_countries="http://192.168.0.148/Election/api/school";
    JsonArrayRequest items = new JsonArrayRequest(URL_countries, new Response.Listener<JSONArray>() {
        @Override
        public void onResponse(JSONArray response) {
            for (int i = 0;i<response.length();i++){
                try {
                    JSONObject obj = response.getJSONObject(i);

                    String country=obj.getString("name_Ar");
                    String cityid = obj.getString("pK_ID");
                    CityId.add(cityid);
                    CityName.add(country);
                }


                catch (JSONException e) {
                    e.printStackTrace();
                }
                city.setAdapter(new ArrayAdapter<String>(Setup.this, android.R.layout.select_dialog_item, CityName));
            }
            //to get me the



        }
    }, new Response.ErrorListener(){

        @Override
        public void onErrorResponse(VolleyError error) {
            AlertDialog.Builder add = new AlertDialog.Builder(Setup.this);
            add.setMessage(error.getMessage()).setCancelable(true);
            AlertDialog alert = add.create();
            alert.setTitle("error");
            alert.show();
        }
    } );


    Controller.getInstance(Setup.this).addToRequestque(items);
    city.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            cityname = parent.getItemAtPosition(position).toString();

            cityid = CityId.get(position).toString();
            //CityId.clear();
            listclasses.clear();
            getclasses();

        } // to close the onItemSelected

        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    classspinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            classname = parent.getItemAtPosition(position).toString();


                class_id = classID.get(position).toString();

        }
        // to close the onItemSelected

        public void onNothingSelected(AdapterView<?> parent) {

        }
    });


    save = (Button) findViewById(R.id.save);
    save.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            sharedpreferences = getSharedPreferences("Settings", Context.MODE_PRIVATE);
            SharedPreferences.Editor editor = sharedpreferences.edit();
            Intent intent =  new Intent(getApplicationContext(), Vote.class);

            editor.putString("schoolname", cityname);
            editor.putString("schoolid", cityid);
            editor.putString("classname", classname);
            editor.putString("classid", class_id);


            editor.apply();
        }
    });
}


public void getschools(){

    try {

        RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
        String URL = "http://192.168.0.148/Election/api/School";
        JSONObject jsonBody = new JSONObject();
        // jsonBody.put("tblRegisteredUsers_nickName", username.getText().toString().trim());
        jsonBody.put("cityFK_ID", cityid);



        final String requestBody = jsonBody.toString();

        StringRequest stringRequest = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                //my response later should be changed

            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e("VOLLEY", error.toString());
            }
        })

        {
            @Override
            public String getBodyContentType() {
                return "application/json; charset=utf-8";
            }

            @Override
            public byte[] getBody() throws AuthFailureError {
                try {
                    return requestBody == null ? null : requestBody.getBytes("utf-8");
                } catch (UnsupportedEncodingException uee) {
                    VolleyLog.wtf("Unsupported Encoding while trying to get the bytes of %s using %s", requestBody, "utf-8");
                    return null;
                }
            }
            @Override
            protected Response<String> parseNetworkResponse(NetworkResponse response) {
                String responseString;
                String json = null;
                try {
                    json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                responseString = String.valueOf(json).trim();
                ArrayList<Schoolresponse> list_response = new ArrayList<Schoolresponse>();
                Type listType = new TypeToken<List<Schoolresponse>>() {}.getType();
                list_response = new Gson().fromJson(responseString, listType);
               // schoolID= new ArrayList<>();
                for (int i = 0; i < list_response.size(); i++) {
                    School listItemData = new School();
                    listItemData.setName(list_response.get(i).getNameAr());
                    listItemData.setId(list_response.get(i).getPKID());

                    //schoolID.add(listItemData.getId());
                    listschools.add(listItemData.getName());
                }

                // i should have this piece of code for methods that are running in the background
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {

                        schoolspinner.setAdapter(new ArrayAdapter<String>(Setup.this, android.R.layout.select_dialog_item, listschools));
                    }
                });


                return Response.success(list_response.toString(), HttpHeaderParser.parseCacheHeaders(response));
            }
        };

        requestQueue.add(stringRequest);
    } catch (JSONException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }





public void getclasses(){

    final  Spinner classspinner = (Spinner) findViewById(R.id.classname);
    try {

        RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext());
        String URL = "http://192.168.0.148/Election/api/classes";
        JSONObject jsonBody = new JSONObject();
        // jsonBody.put("tblRegisteredUsers_nickName", username.getText().toString().trim());
        jsonBody.put("SchoolFK_ID", cityid);



        final String requestBody = jsonBody.toString();

        StringRequest stringRequest = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                //my response later should be changed

            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Log.e("VOLLEY", error.toString());
            }
        })

        {
            @Override
            public String getBodyContentType() {
                return "application/json; charset=utf-8";
            }

            @Override
            public byte[] getBody() throws AuthFailureError {
                try {
                    return requestBody == null ? null : requestBody.getBytes("utf-8");
                } catch (UnsupportedEncodingException uee) {
                    VolleyLog.wtf("Unsupported Encoding while trying to get the bytes of %s using %s", requestBody, "utf-8");
                    return null;
                }
            }
            @Override
            protected Response<String> parseNetworkResponse(NetworkResponse response) {
                String responseString;
                String json = null;
                try {
                    json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                responseString = String.valueOf(json).trim();
                ArrayList<ClassResponse> list_response = new ArrayList<ClassResponse>();
                Type listType = new TypeToken<List<ClassResponse>>() {}.getType();
                list_response = new Gson().fromJson(responseString, listType);
                for (int i = 0; i < list_response.size(); i++) {
                    School listItemData = new School();
                    listItemData.setName(list_response.get(i).getNameAr());
                    listItemData.setId(list_response.get(i).getPKID());

                    classID.add(listItemData.getId());
                    listclasses.add(listItemData.getName());
                }

                // i should have this piece of code for methods that are running in the background
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        classspinner.setAdapter(new ArrayAdapter<String>(Setup.this, android.R.layout.select_dialog_item, listclasses));
                    }
                });
                // String Check =  yourModel.getMessagetitle();

                return Response.success(list_response.toString(), HttpHeaderParser.parseCacheHeaders(response));
            }
        };

        requestQueue.add(stringRequest);
    } catch (JSONException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }

这就是我所说的区域其中只有字符串列表 (listclasses) 存储数据，而整数 (classID) 列表不存储数据

        protected Response<String> parseNetworkResponse(NetworkResponse response) {
                String responseString;
                String json = null;
                try {
                    json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                responseString = String.valueOf(json).trim();
                ArrayList<ClassResponse> list_response = new ArrayList<ClassResponse>();
                Type listType = new TypeToken<List<ClassResponse>>() {}.getType();
                list_response = new Gson().fromJson(responseString, listType);
                for (int i = 0; i < list_response.size(); i++) {
                    School listItemData = new School();
                    listItemData.setName(list_response.get(i).getNameAr());
                    listItemData.setId(list_response.get(i).getPKID());

                    classID.add(listItemData.getId());
                    listclasses.add(listItemData.getName());
                }

                // i should have this piece of code for methods that are running in the background
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        classspinner.setAdapter(new ArrayAdapter<String>(Setup.this, android.R.layout.select_dialog_item, listclasses));
                    }
                });
                // String Check =  yourModel.getMessagetitle();

                return Response.success(list_response.toString(), HttpHeaderParser.parseCacheHeaders(response));
            }
        };

希望我得到正确的答案在此先感谢

【问题讨论】：

嗨，艾哈迈德，您能分享一下 json 响应吗？您是否交叉验证过，如果响应具有您正在寻找的正确标签名称的整数？
stackoverflow.com/users/1075657/sudhin-philip { “pK_ID”：5657，“name_En”：“صف 1”，“name_Ar”：“صف 1”，“fkiD_VotingCenter”：10006，“字母”：“ا”， "isActive": true, "entryDate": null, "enteredBy": null, "updateDate": null, "updatedBy": null },
json 没有问题，我正在使用 pojo https://stackoverflow.com/users/1075657/sudhin-philip

标签： android list gson indexoutofboundsexception

【解决方案1】：

java.lang.IndexOutOfBoundsException：索引：0，大小：0

表示您的 Array 为空，并且您正在尝试从空数组访问数组元素。

您可以设置一个条件来检查数组长度是否大于 0，然后像这样继续使用它：

if(array != null && array.length > 0){
   // do parsing

}

【讨论】：

是的，我知道它是零，但为什么它是零？
尝试调试并查看是否从服务器获取空 JSON 数组。
调试后解决，感谢简单提示looolhttps://stackoverflow.com/users/1439968/ash

【解决方案2】：

确保您的类 School 包含名称为 pK_ID 的变量。仔细查看变量名中的大写/小写。

如果变量名与 JSON 标记不匹配，那么这将导致从 JSON 中提取空，即使您根据您的评论从 URL 获取有效的 JSON。

【讨论】：