我有 JSON 数据加载到对象中，我无法将它们连接到数组适配器以在多个微调器上显示它们

Question

因此，'selectcode.java' class 在向 android 微调器填充值时存在一些问题。代码中没有错误，但问题是我无法将 json 文件中的值检索到微调器。所以我认为我在 JSON 对象 <-> 数组适配器之间的某些地方做错了。谁能解决一下

MainActivity.java

package com.example.app;

import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import org.apache.http.protocol.HTTP;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class MainActivity extends AppCompatActivity {

    String JSON_STRING;

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

    }

    public void addstep1(View view){

        Intent intent = new Intent(this,addcode.class);
        startActivity(intent);
    }

    public void addstep2(View view){
        new BackgroundTask().execute();
        Intent intent= new Intent(this,selectcode.class);
        intent.putExtra("json_data", JSON_STRING);
        startActivity(intent);
    }

    class BackgroundTask extends AsyncTask<Void, Void, String>{

        String json_url="JSON_FILE_URL";

        @Override
        protected String doInBackground(Void... voids){

            try {
                URL url= new URL(json_url);

                HttpURLConnection httpURLConnection= (HttpURLConnection) url.openConnection();
                InputStream inputStream=httpURLConnection.getInputStream();
                BufferedReader bufferedReader= new BufferedReader(new InputStreamReader(inputStream));
                StringBuilder stringBuilder= new StringBuilder();
                while ((JSON_STRING=bufferedReader.readLine())!=null){
                    stringBuilder.append(JSON_STRING+"\n");
                }
                bufferedReader.close();
                inputStream.close();
                httpURLConnection.disconnect();
                return stringBuilder.toString().trim();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;

        }
        @Override
        protected void onPostExecute(String result) {
            JSON_STRING=result;


        }


        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }


        @Override
        protected void onProgressUpdate(Void... values) {
            super.onProgressUpdate(values);
        }
    }



}

Select Code.java

package com.example.app;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

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

import java.util.ArrayList;
import java.util.List;


public class selectcode extends AppCompatActivity  {

    String JSON_STRING;
    List<String> converter = new ArrayList<>();
    List<String> zone = new ArrayList<>();
    List<String> code = new ArrayList<>();
    JSONObject jsonObject;
    JSONArray jsonArray;




    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_selectcode);

        Spinner spinner1=(Spinner) findViewById(R.id.selectconverter);
        ArrayAdapter<String> adapter1=new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, converter);
        adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner1.setAdapter(adapter1);



        Spinner spinner2=(Spinner) findViewById(R.id.selectzone);
        ArrayAdapter<String> adapter2=new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, zone);
        adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner2.setAdapter(adapter2);

        Spinner spinner3=(Spinner) findViewById(R.id.selectcode);
        ArrayAdapter<String> adapter3=new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, code);
        adapter3.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        spinner3.setAdapter(adapter3);




        JSON_STRING= getIntent().getExtras().getString("json_data");
        String converternumber,zonenumber,codeid;

        try {
            jsonObject= new JSONObject(JSON_STRING);
            int count=0;
            jsonArray= jsonObject.getJSONArray("server_response");
            while(count<jsonArray.length()){

                JSONObject JO= jsonArray.getJSONObject(count);
                converternumber= JO.getString("converternumber");
                zonenumber= JO.getString("zonenumber");
                codeid= JO.getString("codeid");

                adapter1.add(converternumber);
                adapter2.add(zonenumber);
                adapter3.add(codeid);

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

    }
    }

JSON 数据：

Connected to database{"server_response":[{"converternumber":"0","zonenumber":"","codeid":""},{"converternumber":"1","zonenumber":"23","codeid":"rg"},{"converternumber":"1","zonenumber":"2a","codeid":"test"},{"converternumber":"2","zonenumber":"1a","codeid":"test"},{"converternumber":"1","zonenumber":"1a","codeid":"test 008"},{"converternumber":"1","zonenumber":"2a","codeid":"test001"},{"converternumber":"1","zonenumber":"a1","codeid":"test001"},{"converternumber":"1","zonenumber":"a1","codeid":"test002"},{"converternumber":"1","zonenumber":"a1","codeid":"test003"},{"converternumber":"1","zonenumber":"a1","codeid":"test004"},{"converternumber":"1","zonenumber":"1a","codeid":"test006"},{"converternumber":"1","zonenumber":"1a","codeid":"test007"},{"converternumber":"1","zonenumber":"1a","codeid":"test008"},{"converternumber":"1","zonenumber":"1a","codeid":"test009"},{"converternumber":"1","zonenumber":"1a","codeid":"test010"},{"converternumber":"1","zonenumber":"1a","codeid":"test111"},{"converternumber":"1","zonenumber":"1a","codeid":"test112"},{"converternumber":"1","zonenumber":"12","codeid":"yx"}]}

Answer 1

您必须在添加项目后通知所有 Spinner 适配器。

 try {
            jsonObject= new JSONObject(JSON_STRING);
            int count=0;
            jsonArray= jsonObject.getJSONArray("server_response");
            while(count<jsonArray.length()){

                JSONObject JO= jsonArray.getJSONObject(count);
                converternumber= JO.getString("converternumber");
                zonenumber= JO.getString("zonenumber");
                codeid= JO.getString("codeid");

                adapter1.add(converternumber);
                adapter2.add(zonenumber);
                adapter3.add(codeid);

                count++;
            }

                adapter1.notifyDataSetChanged();
                adapter2.notifyDataSetChanged();
                adapter3.notifyDataSetChanged();
        } catch (JSONException e) {
            e.printStackTrace();
        }

希望对您有所帮助。

Answer 2

尝试使用此代码

 adapter1.notifyDataSetChanged();
 adapter2.notifyDataSetChanged();
 adapter3.notifyDataSetChanged();

我有 JSON 数据加载到对象中，我无法将它们连接到数组适配器以在多个微调器上显示它们

I have JSON data loaded into objects, I have problem to connect them to array adapter to show them on multiple spinners

android

json

spinner

android-arrayadapter

android-spinner