json应用程序仅从android studio执行

你好吗

在过去的几天里，我构建了我的新jSon应用程序。 它从这个网站获取了earthquak上的params

而且效果很好。但只有当我在谷歌工作室执行时。 如果我关闭应用程序并在手机上手动打开它，我根本看不到任何数据

我的意思是应用程序正在打开，但没有json数据。只有空白屏幕，没有文本视图，也没有列表视图

我在主要活动中使用了以下内容

package com.example.erang.jsonsample;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ListView;

import com.android.volley.Cache;
import com.android.volley.Network;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.BasicNetwork;
import com.android.volley.toolbox.DiskBasedCache;
import com.android.volley.toolbox.HurlStack;
import com.android.volley.toolbox.StringRequest;

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

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    ArrayList<Earthquake> earthquakes = new ArrayList<>();


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

        createJsonRequest();




        // Create an {@link EarthQukeAdapter}, whose data source is a list of {@link earthquake}s. The
        // adapter knows how to create list items for each item in the list.
        EarthQuakeAdapter adapter = new EarthQuakeAdapter(this, earthquakes);

// Find the {@link ListView} object in the view hierarchy of the {@link Activity}.
        // There should be a {@link ListView} with the view ID called list, which is declared in the
        // earthquake_activity.xml layout file.
        ListView listView = (ListView) findViewById(R.id.list);

        // Make the {@link ListView} use the {@link WordAdapter} we created above, so that the
        // {@link ListView} will display list items for each {@link earthquake} in the list.
        listView.setAdapter(adapter);

    }

    @Override
    protected void onStop() {
        super.onStop();

    }

    public void createJsonRequest() {

// Instantiate the cache
        Cache cache = new DiskBasedCache(getCacheDir(), 1024 * 1024); // 1MB cap

// Set up the network to use HttpURLConnection as the HTTP client.
        Network network = new BasicNetwork(new HurlStack());

// Instantiate the RequestQueue with the cache and network.
        RequestQueue mRequestQueue = new RequestQueue(cache, network);

// Start the queue
        mRequestQueue.start();

        String url = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_month.geojson";

// Formulate the request and handle the response.
        StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        //Passing the response
                        parseJsonRequest(response);
                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // Handle error
                    }
                });

// Add the request to the RequestQueue.
        mRequestQueue.add(stringRequest);

    }

    public void parseJsonRequest(String response) {


        if (response != null) {
            // Catch the exception so the app doesn't crash, and print the error message to the logs.
            try {
                JSONObject reader = new JSONObject(response);
                JSONArray features = reader.getJSONArray("features");
                for(int index=0;index<features.length();index++){
                    JSONObject properties = reader.getJSONArray("features").getJSONObject(index).getJSONObject("properties");
                    Double magnitude = properties.getDouble("mag");
                    String place = properties.getString("place");
                    String url = properties.getString("url");
                    //This split between offset location and primary location
                    String[] separated = place.split(",");
                        //If there is missing field jump to the next item
                        if(separated.length < 2){
                            continue;
                        }
                        //This contain the offsetLocation
                        String offsetLocation = separated[0];
                        //This contain the primaryLocation
                        separated[1] = separated[1].trim();
                        String primaryLocation = separated[1];
                    //Passing date twice one for the date and one for the time.
                    String updateDate = properties.getString("time");
                    java.util.Date date=new java.util.Date(Long.valueOf(updateDate) );
                     //The second date passing the time
                    earthquakes.add(new Earthquake(magnitude, offsetLocation, primaryLocation, date, date, url));

                }


            } catch (JSONException e) {
                // If an error is thrown when executing any of the above statements in the "try" block,
                // catch the exception here, so the app doesn't crash. Print a log message
                // with the message from the exception.
                Log.e("QueryUtils", "Problem parsing the earthquake JSON results", e);
            }
        }

    }

}

你知道为什么我的应用程序只有在android Studio上运行时才会运行良好吗

在清单文件中，我还添加了

<uses-permission android:name="android.permission.INTERNET" />

非常感谢

Eran

公共类MainActivity扩展了AppCompatActivity{
ArrayList地震=新ArrayList（）；
地震适配器；
列表视图列表视图；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
createJsonRequest（）；
listView=（listView）findViewById（R.id.list）；
}
@凌驾
受保护的void onStop（）{
super.onStop（）；
}
public void createJsonRequest（）{
//实例化缓存
Cache Cache=new DiskBasedCache（getCacheDir（），1024*1024）；//1MB上限
//设置网络以使用HttpURLConnection作为HTTP客户端。
网络=新的基本网络（new HurlStack（））；
//使用缓存和网络实例化RequestQueue。
RequestQueue MRRequestQueue=新的RequestQueue（缓存，网络）；
//启动队列
mRequestQueue.start（）；
字符串url=”https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_month.geojson";
//制定请求并处理响应。
StringRequest StringRequest=新的StringRequest（Request.Method.GET，url，
新的Response.Listener（）{
@凌驾
公共void onResponse（字符串响应）{
//传递响应
parseJsonRequest（响应）；
适配器=新的地震适配器（main activity.this，地震）；
setAdapter（适配器）；
}
},
新的Response.ErrorListener（）{
@凌驾
公共无效onErrorResponse（截击错误）{
//处理错误
}
});
//将请求添加到RequestQueue。
mRequestQueue.add（stringRequest）；
}
公共void parseJsonRequest（字符串响应）{
if（响应！=null）{
//捕获异常以便应用程序不会崩溃，并将错误消息打印到日志中。
试一试{
JSONObject reader=新的JSONObject（响应）；
JSONArray features=reader.getJSONArray（“features”）；
对于（int index=0；index1），我能够解决这个问题。
首先，我在看另一个使用Async的实现，我看到有一个onPostExecute方法在PostExecute上运行。
当我使用截击时，我寻找类似的东西。
我知道我需要使用OnResponse方法。
所以我换了3行代码

@Override
 public void onResponse(String response) {
//Passing the response
parseJsonRequest(response);

EarthQuakeAdapter adapter = new EarthQuakeAdapter(MainActivity.this, earthquakes);

ListView listView = (ListView) findViewById(R.id.list);

listView.setAdapter(adapter);
   }
},

在OnResponse中，因此只有在填充数组后，我才会创建适配器并将其添加到列表视图中。
为什么它会为null。？首先，我没有得到任何异常。其次，我在这一行填充数组。添加（新地震（震级、偏移位置、原始位置、日期、日期、url））；为什么它在Studio中执行时效果很好，而在手动执行时则会有所不同？我已经编辑了您的问题，请尝试。您的示例中的一个问题是listView.setAdapter（adapter）；它在onCreate中定义，但在OnResponse中没有识别。但是我缺少创建数组的那一行。如果您完全删除它，只需做一件事，在parseJsonRequest（response）之后在代码中添加这一行适配器。notifyDataSetChanged（）；没有帮助…但是感谢您的努力Mohammad.，：-）
public class MainActivity extends AppCompatActivity {

ArrayList<Earthquake> earthquakes = new ArrayList<>();
EarthQuakeAdapter adapter;
ListView listView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    createJsonRequest();
    listView = (ListView) findViewById(R.id.list);
}

@Override
protected void onStop() {
    super.onStop();

}

public void createJsonRequest() {

// Instantiate the cache
    Cache cache = new DiskBasedCache(getCacheDir(), 1024 * 1024); // 1MB cap

// Set up the network to use HttpURLConnection as the HTTP client.
    Network network = new BasicNetwork(new HurlStack());

// Instantiate the RequestQueue with the cache and network.
    RequestQueue mRequestQueue = new RequestQueue(cache, network);

// Start the queue
    mRequestQueue.start();

    String url = "https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/2.5_month.geojson";

// Formulate the request and handle the response.
    StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
            new Response.Listener<String>() {
                @Override
                public void onResponse(String response) {
                    //Passing the response
                    parseJsonRequest(response);

                    adapter = new EarthQuakeAdapter(MainActivity.this, earthquakes);
                    listView.setAdapter(adapter);
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    // Handle error
                }
            });

// Add the request to the RequestQueue.
    mRequestQueue.add(stringRequest);

}

public void parseJsonRequest(String response) {


    if (response != null) {
        // Catch the exception so the app doesn't crash, and print the error message to the logs.
        try {
            JSONObject reader = new JSONObject(response);
            JSONArray features = reader.getJSONArray("features");
            for(int index=0;index<features.length();index++){
                JSONObject properties = reader.getJSONArray("features").getJSONObject(index).getJSONObject("properties");
                Double magnitude = properties.getDouble("mag");
                String place = properties.getString("place");
                String url = properties.getString("url");
                //This split between offset location and primary location
                String[] separated = place.split(",");
                //If there is missing field jump to the next item
                if(separated.length < 2){
                    continue;
                }
                //This contain the offsetLocation
                String offsetLocation = separated[0];
                //This contain the primaryLocation
                separated[1] = separated[1].trim();
                String primaryLocation = separated[1];
                //Passing date twice one for the date and one for the time.
                String updateDate = properties.getString("time");
                java.util.Date date=new java.util.Date(Long.valueOf(updateDate) );
                //The second date passing the time
                earthquakes.add(new Earthquake(magnitude, offsetLocation, primaryLocation, date, date, url));

            }


        } catch (JSONException e) {
            // If an error is thrown when executing any of the above statements in the "try" block,
            // catch the exception here, so the app doesn't crash. Print a log message
            // with the message from the exception.
            Log.e("QueryUtils", "Problem parsing the earthquake JSON results", e);
        }
    }

}

}

@Override
 public void onResponse(String response) {
//Passing the response
parseJsonRequest(response);

EarthQuakeAdapter adapter = new EarthQuakeAdapter(MainActivity.this, earthquakes);

ListView listView = (ListView) findViewById(R.id.list);

listView.setAdapter(adapter);
   }
},