在 android spinner 中填充 json 数组

Question

我在 android spinner 中解析 json 时遇到问题。我已经尝试过下面列出的代码，但我在微调器中得到了完整的 json 数组，如屏幕截图

我的 Json 数组

{"Department":[{"1":"Computer"},{"2":"IT"},{"3":"Civil"}]} // like this type json string

我的代码

public class GetDropdownItems extends AsyncTask<Void, Void, String[]> {
        public GetDropdownItems() {
            super();
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            Log.i("MY_NETWORK", "first");
        }

        @Override
        protected String[] doInBackground(Void... params) {
            StringBuilder sbstaffdep = new StringBuilder();
            String staffdepURL = StaticDataEntity.URL_GETDEP;
            String charset = "UTF-8";  // Or in Java 7 and later, use the constant: java.nio.charset.StandardCharsets.UTF_8.name()
            URLConnection connectionstaffDep = null;
            try {
                connectionstaffDep = new URL(staffdepURL).openConnection();
            } catch (IOException e) {
                e.printStackTrace();
            }

            connectionstaffDep.setDoOutput(true); // Triggers POST.
            connectionstaffDep.setRequestProperty("Accept-Charset", charset);
            connectionstaffDep.setConnectTimeout(6000);

            InputStream responsestaffDep = null;
            try {
                responsestaffDep = connectionstaffDep.getInputStream();
            } catch (IOException e) {
                e.printStackTrace
                        ();
                return new String[]{"unreachable"};

            }

            BufferedReader brstaffDep = new BufferedReader(new InputStreamReader(responsestaffDep));
            String readstaffDep;
            try {

                while ((readstaffDep = brstaffDep.readLine()) != null) {
                    //System.out.println(read);
                    sbstaffdep.append(readstaffDep);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

            try {

                brstaffDep.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            String[] finaldata = new String[1];
            finaldata[0] = sbstaffdep.toString();
            return finaldata;
        }

        @Override
        protected void onPostExecute(String[] s) {
            super.onPostExecute(s);

            if (s[0].equals("unreachable")) {
                new SweetAlertDialog(SignUpStaff.this, SweetAlertDialog.ERROR_TYPE)
                        .setTitleText("Oops...")
                        .setContentText("Unable to connect to server ! \n Please try again later.")
                        .setCancelText("Ok")
                        .setCancelClickListener(new SweetAlertDialog.OnSweetClickListener() {
                            @Override
                            public void onClick(SweetAlertDialog sweetAlertDialog) {
                                sweetAlertDialog.cancel();
                            }
                        })
                        .show();
                return;
            }
            Log.i("MY_NETWORK", s.toString());
            String[] dataofdropdowndep = s[0].split(",");
            ArrayAdapter<String> adapterdep = new ArrayAdapter<String>(SignUpStaff.this, android.R.layout.simple_list_item_1, dataofdropdowndep);
            adapterdep.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            dropstaffdep.setAdapter(adapterdep);
        }
    }

Answer 1

public class GetDropdownItems extends AsyncTask<Void, Void, String> {
        public GetDropdownItems() {
            super();
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            Log.i("MY_NETWORK", "first");
        }

        @Override
        protected String doInBackground(Void... params) {
            StringBuilder sbstaffdep = new StringBuilder();
            String staffdepURL = StaticDataEntity.URL_GETDEP;
            String charset = "UTF-8";  // Or in Java 7 and later, use the constant: java.nio.charset.StandardCharsets.UTF_8.name()
            URLConnection connectionstaffDep = null;
            try {
                connectionstaffDep = new URL(staffdepURL).openConnection();
            } catch (IOException e) {
                e.printStackTrace();
            }

            connectionstaffDep.setDoOutput(true); // Triggers POST.
            connectionstaffDep.setRequestProperty("Accept-Charset", charset);
            connectionstaffDep.setConnectTimeout(6000);

            InputStream responsestaffDep = null;
            try {
                responsestaffDep = connectionstaffDep.getInputStream();
            } catch (IOException e) {
                e.printStackTrace
                        ();
                return "unreachable";

            }
try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    responsestaffDep, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();

            Log.d("-------------", json);
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }


            return json;
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);

            if (s.equals("unreachable")) {
                new SweetAlertDialog(SignUpStaff.this, SweetAlertDialog.ERROR_TYPE)
                        .setTitleText("Oops...")
                        .setContentText("Unable to connect to server ! \n Please try again later.")
                        .setCancelText("Ok")
                        .setCancelClickListener(new SweetAlertDialog.OnSweetClickListener() {
                            @Override
                            public void onClick(SweetAlertDialog sweetAlertDialog) {
                                sweetAlertDialog.cancel();
                            }
                        })
                        .show();
                return;
            }
            Log.i("MY_NETWORK", s.toString());
            Json js=new Json(s);
JSONArray array=js.getJSONArray("Department");
for(JSONArray b:array){
// traverse array here
}
            ArrayAdapter<String> adapterdep = new ArrayAdapter<String>(SignUpStaff.this, android.R.layout.simple_list_item_1, dataofdropdowndep);
            adapterdep.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            dropstaffdep.setAdapter(adapterdep);
        }
    }

Answer 2

HI 从服务器更改您的 Json 响应，或者您可以手动更改。

这是你的格式：

{"Department"
 [
  {
   "1": "Computer"
  },
  {
   "2": "IT"
  },
  {
   "3": "Civil"
  }
 ]
}

请在线查看任何 json 查看器格式。

Answer 3

这种类型的json数据： 检查这个 json 数组：

{
    "schools": [{
        "Name": "Hill View Elementary",
        "SchoolID": "HVE"
    }, {
        "Name": "Mill View",
        "SchoolID": "MVE"
    }, {
        "Name": "Big School",
        "SchoolID": "BSC"
    }]
}

你的错误是你没有在两个对象之间放置逗号

Answer 4

你获取 Json 文件的方式不对，已经有 Json 类可以单独获取每个数组、对象或键。

org.json 是我们将与JSONArray 和JSONObject 类一起使用的库。

在我们开始之前，你应该对 Json 文件方案有一个基本的了解：

"name":{}这是用{}符号表示的数组语法，这个数组可以存放数组、对象或键。

[] 代表和对象，它也可以保存数组和键，但它没有名称。

"key":"value" 现在是键类型，它可以保存您想要的数据或值，并有一个键来按名称检索它。

现在这里有一段代码来获取您的文件并单独获取 Json 文件的每个部分，然后您可以根据需要填充它。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.content.res.Resources;

public class Fetch {

    final private static String DEPARTMENT = "Department";
    String [] departments ;


    public void fetch(Resources r , int resourceID) {
        String JsonString = readStringFromRaw(r, resourceID);
        //the whole josn file is a json object even if it starts with { and ends with } so...
        try {

            JSONObject mainObject = new JSONObject(JsonString);
            // the JSONObject throws a JSONException if there is something wrong with the syntax
            JSONArray department = mainObject.getJSONArray(DEPARTMENT);

            int length = department.length();

            departments = new String[length];

            JSONObject object;
            for(int i = 0 ; i < length ; i++){
            object = department.getJSONObject(i);
            departments[0] = object.getString(""+i+1);
            //this because you tagged the keys with 1 , 2 , 3 and so on.. so it has the value of the object that it is in + 1 . 
            //the reason I put "" empty quotations is because I want it a string so this is a way to cast the numbers to strings .

            }


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

    }

    public static String readStringFromRaw(Resources r, int resourceID) {
        InputStream is = r.openRawResource(resourceID);
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder(1000);
        String line;
        try {
            while ((line = br.readLine()) != null)
                sb.append(line);
            br.close();
            is.close();
            return sb.toString();
        } catch (IOException e) {
            return e.getMessage();
        }
    }
}

通过这个类，您可以获得一个字符串数组，其中包含您想要的 json 文件的部门。

数组和对象之间的层次结构非常重要，因此请记住，当您编写 json 文件时，可以更轻松地提取信息。