Question

我正在开发一个应用程序，我需要从互联网上获取一些数据，如名称和电子邮件，我看了一些关于如何使用volley来解析JSON文件并从互联网上获取数据的教程我想在ListView中显示一些数据（JSON文件中的所有名称），但是当我运行它时我的应用程序崩溃了，这是一个简化的代码：

public class MainActivity extends Activity {

// json array response url
private String urlJsonArry = "https://api.myjson.com/bins/1d60wu";
private String jsonResponse;
ListView nameList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    nameList = (ListView) findViewById(R.id.nameList);


    JsonArrayRequest req = new JsonArrayRequest(urlJsonArry,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {

                    try {

                        ArrayList al = new ArrayList();

                        for (int i = 0; i < response.length(); i++) {

                            JSONObject person = (JSONObject) response
                                    .get(i);

                            // al.add(response.get(i));
                            al.add(person.getString("name"));

                        }

                        ArrayAdapter adapter = new ArrayAdapter(getApplicationContext(), android.R.layout.simple_list_item_1, al);
                        nameList.setAdapter(adapter);

                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(getApplicationContext(),
                                "Error: " + e.getMessage(),
                                Toast.LENGTH_LONG).show();
                    }


                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d(TAG, "Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });

    // Adding request to request queue
    RequestQueue rQueue = Volley.newRequestQueue(MainActivity.this);
    rQueue.add(req);
}}

JSON CODE

    [
  {
    "name": "Ravi Tamada",
    "email": "ravi8x@gmail.com",
    "phone": {
      "home": "08947 000000",
      "mobile": "9999999999"
    }
  },
  {
    "name": "opeyemi sanusi",
    "email": "rffddg@gmail.com",
    "phone": {
      "home": "08457 000000",
      "mobile": "999944999"
    }
  },
  {
    "name": "james bond",
    "email": "dfgdg@gmail.com",
    "phone": {
      "home": "05657 000000",
      "mobile": "999944999"
    }
  },
  {
    "name": "Tommy",
    "email": "tommy@gmail.com",
    "phone": {
      "home": "08946 000000",
      "mobile": "0000000000"
    }
  }
]

我只想获得listview中显示的每个数组中的名称，即Ravi Tamada，opeyemi Sanusi，James bond等

Answer 1

您可以更换下面的请求代码，但不会遇到崩溃。我还检查了我的设备，现在我可以用数组填充listview。并且你不要忘记在清单中允许互联网。

 StringRequest req = new StringRequest(urlJsonArry,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {

                    try {

                        ArrayList al = new ArrayList();
                        JSONArray jsonArray = new JSONArray(response);
                        for (int i = 0; i < jsonArray.length(); i++) {
                            JSONObject jsonObject = jsonArray.getJSONObject(i);
                            if (jsonObject.has("name")) {
                                al.add(jsonObject.getString("name"));
                            }
                        }

                        ArrayAdapter adapter = new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1, al);
                        nameList.setAdapter(adapter);

                    } catch (JSONException e) {
                        e.printStackTrace();
                        Toast.makeText(getApplicationContext(),
                                "Error: " + e.getMessage(),
                                Toast.LENGTH_LONG).show();
                    }


                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d("Error", "Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_SHORT).show();
        }
    });

    // Adding request to request queue
    RequestQueue rQueue = Volley.newRequestQueue(MainActivity.this);
    rQueue.add(req);

Answer 2

setContentView(R.layout.activity_main);失踪了。

此代码可以正常工作

package com.radline.radapp.radapp;

import android.app.Activity;
import android.os.Bundle;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

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

import java.util.ArrayList;


public class MainActivity extends Activity {

    String urlJsonArry = "https://api.myjson.com/bins/1d60wu";
    ListView nameList;

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

        nameList = (ListView) findViewById(R.id.nameList);

        StringRequest req = new StringRequest(urlJsonArry,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        try {

                            ArrayList al = new ArrayList();
                            JSONArray jsonArray = new JSONArray(response);
                            for (int i = 0; i < jsonArray.length(); i++) {
                                JSONObject jsonObject = jsonArray.getJSONObject(i);
                                if (jsonObject.has("name")) {
                                    al.add(jsonObject.getString("name"));
                                }
                            }

                            ArrayAdapter adapter = new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1, al);
                            nameList.setAdapter(adapter);

                        } catch (JSONException e) {
                            e.printStackTrace();
                            Toast.makeText(getApplicationContext(),
                                    "Error: " + e.getMessage(),
                                    Toast.LENGTH_LONG).show();
                        }


                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                VolleyLog.d("Error", "Error: " + error.getMessage());
                Toast.makeText(getApplicationContext(),
                        error.getMessage(), Toast.LENGTH_SHORT).show();
            }
        });

        // Adding request to request queue
        RequestQueue rQueue = Volley.newRequestQueue(MainActivity.this);
        rQueue.add(req);
    }
}

如何使用齐射将json文件解析为Listview

2 个答案: