Question

我从URL获取JSON数据，然后在MainActivity的ListView中显示它。我已经与JSON文件URL建立了正确的连接，并且我能够将URL中的数据提取到字符串中，但现在我尝试使用ListAdapter在ListView中显示它，但它没有显示任何数据。

我的JSON数据如下：

{
    "result": 1,
    "data": [{
        "id": 1,
        "name": "Aconitum",
        "url": "https:\/\/upload.wikimedia.org\/wikipedia\/commons\/7\/7e\/Aconitum_degenii.jpg"
    },
    {
        "id": 2,
        "name": "African lily",
        "url": "http:\/\/i1.wp.com\/cottagegardenflowershop.co.uk\/wp-content\/uploads\/2014\/09\/1040668-90x90.jpg?ssl=1"
    },
    {
        "id": 3,
        "name": "Alpine thistle",
        "url": "http:\/\/i1.wp.com\/cottagegardenflowershop.co.uk\/wp-content\/uploads\/2014\/09\/1040668-90x90.jpg?ssl=1"
    },

我将数据以hashmap的形式存储在此格式的arrayList中。的ArrayList＆GT; contactList;

我的主要活动.java是：

package com.example.hsports.flowers;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

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

import java.util.ArrayList;
import java.util.HashMap;

public class MainActivity extends AppCompatActivity {

    public static String url="http://development.easystartup.org/NO/Backend/flower.php";

    private String TAG = MainActivity.class.getSimpleName();

    private ProgressDialog pDialog;
    private ListView lv;

    ArrayList<HashMap<String, String>> contactList;


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

        contactList = new ArrayList<>();

        lv = (ListView) findViewById(R.id.listview);

        new GetContacts().execute();




        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {


               String url=contactList.get(position).get("url");
                System.out.println("hello");






            }
        });

    }



    private class GetContacts extends AsyncTask<Void, Void, Void> {

        @Override
        protected Void doInBackground(Void... arg0) {
            HttpHandler sh = new HttpHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url);

            Log.e(TAG, "Response from url: " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    JSONArray contacts = jsonObj.getJSONArray("data");

                    // looping through All Contacts
                    for (int i = 0; i < 28; i++) {
                        JSONObject c = contacts.getJSONObject(i);


                        if(c==null)
                        {
                            continue;

                        }

                        String id = c.getString("id");
                        String name = c.getString("name");
                        String urlInjson = c.getString("url");
                        //String address = c.getString("address");
                        //String gender = c.getString("gender");



                        // tmp hash map for single contact
                        HashMap<String, String> contact = new HashMap<>();

                        // adding each child node to HashMap key => value
                        contact.put("id", id);
                        contact.put("name", name);
                        contact.put("url", urlInjson);


                        // adding contact to contact list
                        contactList.add(contact);
                    }
                } catch (final JSONException e) {
                    Log.e(TAG, "Json parsing error: " + e.getMessage());
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Toast.makeText(getApplicationContext(),
                                    "Json parsing error: " + e.getMessage(),
                                    Toast.LENGTH_LONG)
                                    .show();
                        }
                    });

                }
            } else {
                Log.e(TAG, "Couldn't get json from server.");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Toast.makeText(getApplicationContext(),
                                "Couldn't get json from server. Check LogCat for possible errors!",
                                Toast.LENGTH_LONG)
                                .show();
                    }
                });

            }

            return null;
        }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }



        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, contactList,
                    R.layout.support_simple_spinner_dropdown_item, new String[]{"name"}, new int[]{R.id.flowerName});



            lv.setAdapter(adapter);
        }

    }


}

我怎样才能填充＆＃34; name＆＃34;来自ListView中的Arraylist？

Answer 1

此声明应该有变化：

ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, contactList,
                    R.layout.support_simple_spinner_dropdown_item, new String[]{"name"}, new int[]{R.id.flowerName});

应该给出R.layout.list_view，其中这是定义ListView布局的视图。

从URL中获取JSON数据，然后在android中的ListView中显示它

1 个答案: