如何在可扩展列表视图中绑定 Json 数据？

Posted 2023-02-16

【中文标题】如何在可扩展列表视图中绑定 Json 数据？

【英文标题】：How to Bind Json Data in Expandale List view?

【发布时间】：2017-10-04 09:00:52

【问题描述】：

我想将 json 数据绑定到 android 中的可扩展列表视图。 显示以下错误

错误：

Error:(175, 65) error: incompatible types: MainActivity.ExecuteTask cannot be converted to Context

Json 数据：

    ["PART_ID":"01684.021","SHIFT_DATE":"20-SEP-17","PLAN_QTY":"2","ACTUAL_QTY":"2",
"PART_ID":"0346001.020","SHIFT_DATE":"20-SEP-17","PLAN_QTY":"4","ACTUAL_QTY":"4",
"PART_ID":"01068.021","SHIFT_DATE":"20-SEP-17","PLAN_QTY":"7","ACTUAL_QTY":"7"]

ExpandableListAdapter.java

package com.example.saravanakumars.expandable_listview;

import android.content.Context;
import android.graphics.Typeface;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseExpandableListAdapter;
import android.widget.TextView;
import java.util.HashMap;
import java.util.List;
/**
 * Created by saravanakumars on 10/3/2017.
 */

public class ExpandableListAdapter extends BaseExpandableListAdapter 
    private Context _context;
    private List<String> _listDataHeader; // header titles
    // child data in format of header title, child title
    private HashMap<String, List<String>> _listDataChild;

//    ArrayList<TerbaruModel>ListTerbaru;
//    ArrayList<ArrayList<ChildTerbaru>> ListChildTerbaru;
//    int count;
    public ExpandableListAdapter(Context context, List<String> listDataHeader,
                                 HashMap<String, List<String>> listChildData) 
        this._context = context;
        this._listDataHeader = listDataHeader;
        this._listDataChild = listChildData;
    

    @Override
    public Object getChild(int groupPosition, int childPosititon) 
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .get(childPosititon);
    

    @Override
    public long getChildId(int groupPosition, int childPosition) 
        return childPosition;
    

    @Override
    public View getChildView(int groupPosition, final int childPosition,
                             boolean isLastChild, View convertView, ViewGroup parent) 

        final String childText = (String) getChild(groupPosition, childPosition);

        if (convertView == null) 
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_item, null);
        

        TextView txtListChild = (TextView) convertView
                .findViewById(R.id.lblListItem);

        txtListChild.setText(childText);
        return convertView;
    

    @Override
    public int getChildrenCount(int groupPosition) 
        return this._listDataChild.get(this._listDataHeader.get(groupPosition))
                .size();
    

    @Override
    public Object getGroup(int groupPosition) 
        return this._listDataHeader.get(groupPosition);
    

    @Override
    public int getGroupCount() 
        return this._listDataHeader.size();
    

    @Override
    public long getGroupId(int groupPosition) 
        return groupPosition;
    

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
                             View convertView, ViewGroup parent) 
        String headerTitle = (String) getGroup(groupPosition);
        if (convertView == null) 
            LayoutInflater infalInflater = (LayoutInflater) this._context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = infalInflater.inflate(R.layout.list_group, null);
        

        TextView lblListHeader = (TextView) convertView
                .findViewById(R.id.lblListHeader);
        lblListHeader.setTypeface(null, Typeface.BOLD);
        lblListHeader.setText(headerTitle);

        return convertView;
    

    @Override
    public boolean hasStableIds() 
        return false;
    

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) 
        return true;
    

MainActivity.java

package com.example.saravanakumars.expandable_listview;

import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ExpandableListView;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class MainActivity extends AppCompatActivity

    ExpandableListAdapter listAdapter;
    ExpandableListView expListView;
    List<String> listDataHeader;
    HashMap<String, List<String>> listDataChild;


    String s1 = "CLASIFICACION";
    String s2 = "ONE PIECE";
    String s3 = "159-OP SHERIDAN";


    private String TAG = MainActivity.class.getSimpleName();
    private ProgressDialog pDialog;
    private static String url = "http://113.193.30.155/MobileService/MobileService.asmx/GetPartbyProcessFamilyModel";

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

//        expListView = (ExpandableListView) findViewById(R.id.lvExp);
//
//        // preparing list data
//        prepareListData();
//
//        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);
//
//        // setting list adapter
//        expListView.setAdapter(listAdapter);


        new ExecuteTask().execute(s1, s2, s3);


    

    /*
     * Preparing the list data
//     */
//    private void prepareListData() 
//        listDataHeader = new ArrayList<String>();
//        listDataChild = new HashMap<String, List<String>>();
//
//        // Adding child data
//        listDataHeader.add("Defect");
//        listDataHeader.add("Production");
//        listDataHeader.add("Report");
//
//        // Adding child data
//        List<String> Defect = new ArrayList<String>();
//        Defect.add("Defect-1");
//        Defect.add("Defect-2");
//        Defect.add("Defect-3");
//        Defect.add("Defect-4");
//        Defect.add("Defect-5");
//
//
//        List<String> Production = new ArrayList<String>();
//        Production.add("Production-1");
//        Production.add("Production-2");
//        Production.add("Production-3");
//        Production.add("Production-4");
//        Production.add("Production-5");
//
//
//        List<String> Report = new ArrayList<String>();
//        Report.add("Report-1");
//        Report.add("Report-2");
//        Report.add("Report-3");
//        Report.add("Report-4");
//        Report.add("Report-5");
//
//        listDataChild.put(listDataHeader.get(0), Defect); // Header, Child data
//        listDataChild.put(listDataHeader.get(1), Production);
//        listDataChild.put(listDataHeader.get(2), Report);
//    

    class ExecuteTask extends AsyncTask<String, Integer, String> 

        @Override
        protected String doInBackground(String... params) 

            String res = PostData(params);

            return res;

        

        @Override
        protected void onPostExecute(String result) 
            super.onPostExecute(result);
//                Toast.makeText(getApplicationContext(),
//                        result,Toast.LENGTH_LONG)
//                        .show();

            fetchResponse(result.replace("\n", "").trim());
            pDialog.dismiss();

        

        private void fetchResponse(String result) 
            if (!result.equals("")) 
                try 
                    JSONArray jsonArray = new JSONArray(result);

                    expListView = (ExpandableListView) findViewById(R.id.lvExp);

                    listDataHeader = new ArrayList<String>();
                    listDataChild = new HashMap<String, List<String>>();

                    // Adding child data
                    listDataHeader.add("SHIFT_DATE");
                    listDataHeader.add("PART_ID");
                    listDataHeader.add("PLAN_QTY");

                    // Adding child data
                    List<String> SHIFT_DATE = new ArrayList<String>();
                    for (int i = 0; i < jsonArray.length(); i++) 

                        JSONObject jsonObject = jsonArray.getJSONObject(i);
                        jsonObject = jsonArray.getJSONObject(i);
                        SHIFT_DATE.add(jsonObject.getString("SHIFT_DATE"));
                    

                    List<String> PART_ID = new ArrayList<String>();
                    for (int i = 0; i < jsonArray.length(); i++) 

                        JSONObject jsonObject1 = jsonArray.getJSONObject(i);
                        jsonObject1 = jsonArray.getJSONObject(i);
                        PART_ID.add(jsonObject1.getString("PART_ID"));
                    


                    List<String> PLAN_QTY = new ArrayList<String>();
                    for (int i = 0; i < jsonArray.length(); i++) 

                        JSONObject jsonObject2 = jsonArray.getJSONObject(i);
                        jsonObject2 = jsonArray.getJSONObject(i);
                        PLAN_QTY.add(jsonObject2.getString("PLAN_QTY"));
                    

                    listDataChild.put(listDataHeader.get(0), SHIFT_DATE); // Header, Child data
                    listDataChild.put(listDataHeader.get(1), PART_ID);
                    listDataChild.put(listDataHeader.get(2), PLAN_QTY);

//
                        listAdapter = new ExpandableListAdapter(this, listDataHeader, listDataChild);

                    // setting list adapter
                    expListView.setAdapter(listAdapter);

                 catch (JSONException e) 
                    e.printStackTrace();
                
            
        


        public String PostData(String[] valuse) 
            String s = "";
            try 
                HttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost("http://113.193.30.155/MobileService/MobileService.asmx/GetPartbyProcessFamilyModel");

                List<BasicNameValuePair> list = new ArrayList<BasicNameValuePair>();
                list.add(new BasicNameValuePair("strProcess", s1));
                list.add(new BasicNameValuePair("strFamily", s2));
                list.add(new BasicNameValuePair("strModel", s3));
                httpPost.setEntity(new UrlEncodedFormEntity(list));
                HttpResponse httpResponse = httpClient.execute(httpPost);

                HttpEntity httpEntity = httpResponse.getEntity();

                s = readResponse(httpResponse);

//            HttpEntity entity = httpResponse.getEntity();
//
//            s = EntityUtils.toString(entity);

             catch (Exception exception) 
            
            return s;


        

        public String readResponse(HttpResponse res) 
            InputStream is = null;
            String return_text = "";
            try 
                is = res.getEntity().getContent();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(is));
                String line = "";
                StringBuffer sb = new StringBuffer();
                while ((line = bufferedReader.readLine()) != null) 
                    sb.append(line);
                
                return_text = sb.toString();
             catch (Exception e) 

            
            return return_text;

        

    

帮我解决这个问题。

【问题讨论】：

Java 基础知识：this 关键字是什么以及它是如何工作的...

How can "this" of the outer class be accessed from an inner class?的可能重复

【参考方案1】：

改变这个：

listAdapter = new ExpandableListAdapter(this,listDataHeader,listDataChild);

到：

   listAdapter = new ExpandableListAdapter(MainActivity.this, listDataHeader, listDataChild);

【讨论】：

日志猫：致命异常：主进程：com.example.saravanakumars.expandable_listview，PID：20712 java.lang.NullPointerException：尝试调用虚拟方法'void android.app.ProgressDialog.dismiss() ' 在空对象引用上