发送请求时不加载java JSON数据

Question

我正在尝试构建一个JSON请求应用程序。它从这个网站上获取了有关地震的信息”https://earthquake.usgs.gov/fdsnws/event/1/query“。我面临的问题是，当应用程序活动开始时，进度条是可见的，但没有显示JSON数据，也没有显示textview，只是进度条一直加载到最后。我尝试了，但无法解决错误所在。请帮助我，我只是在这里停留了几天。提前谢谢

我的主要活动代码

package com.example.volleyearthquake;

import 安卓x.appcompat.app.AppCompatActivity;
import 安卓x.recyclerview.widget.LinearLayoutManager;
import 安卓x.recyclerview.widget.RecyclerView;

import 安卓.content.Context;
import 安卓.net.ConnectivityManager;
import 安卓.net.NetworkInfo;
import 安卓.os.Bundle;
import 安卓.util.Log;
import 安卓.view.View;
import 安卓.widget.ProgressBar;
import 安卓.widget.TextView;

import com.安卓.volley.Request;
import com.安卓.volley.RequestQueue;
import com.安卓.volley.Response;
import com.安卓.volley.VolleyError;
import com.安卓.volley.toolbox.JsonArrayRequest;
import com.安卓.volley.toolbox.JsonObjectRequest;
import com.安卓.volley.toolbox.Volley;

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

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    private RequestQueue mRequestQueue;
    private ArrayList<Earthquake> mEarthquake;
    private RecyclerView mRecycleView;
    private EarthquakeAdapter adapter;

    boolean isConnected;
    /**
     * Textview to be displayed when the listview have no data
     */
    TextView emptyView;
    /**
     * Progressbar variable which is circular spinner (loading indicator)
     */
    ProgressBar loadingIndicator;
    private static final String USS_REQUEST_URL = "https://earthquake.usgs.gov/fdsnws/event/1/query";

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

        final ConnectivityManager cm = (ConnectivityManager) this.getSystemService(Context.CONNECTIVITY_SERVICE);

        Read_network_state(cm);
        loadingIndicator = findViewById(R.id.loading_indicator);
        emptyView = findViewById(R.id.empty_view);

        mRecycleView = findViewById(R.id.recycle_list);
        mRecycleView.setHasFixedSize(true);
        LinearLayoutManager manager = new LinearLayoutManager(this);
        mRecycleView.setLayoutManager(manager);
        mEarthquake = new ArrayList<>();
        adapter = new EarthquakeAdapter(MainActivity.this, mEarthquake);

        mRecycleView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
        mRequestQueue = Volley.newRequestQueue(this);
        parseEarthquake();

    }

    private void parseEarthquake() {

        final JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, USS_REQUEST_URL,
                null, response -> {

            try {
                JSONArray feature = response.getJSONArray("features");
                for (int index = 0; index < feature.length(); index++) {
                    JSONObject features = feature.getJSONObject(index);
                    JSONObject properties = features.getJSONObject("properties");
                    Double magnitude = properties.getDouble("mag");
                    String location = properties.getString("place");
                    long time = properties.getLong("time");
                    String url = properties.getString("url");

                    mEarthquake.add(new Earthquake(magnitude, location, time, url));
                }

            } catch (JSONException e) {
                e.printStackTrace();
            }
        }, error -> {

        });
        mRequestQueue.add(request);
    }

    public void Read_network_state(ConnectivityManager connectivityManager) {

        NetworkInfo activeNetwork = connectivityManager.getActiveNetworkInfo();
        if (activeNetwork != null && activeNetwork.isConnectedOrConnecting()) {
            isConnected = true;
            Log.d("Ruhul", "CONNECTED TO INTERNET");
        } else {
            isConnected = false;
        }
    }
}

在清单文件中，我还添加了

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

Answer 1

首先必须解析地震，然后将其放入recyclerView中，如果仍然有错误，请尝试一步一步地跟踪您的请求，并检查locat以确保正确解析json，并且在解析时没有错误， 提示：当解析应用程序时发生错误时，json不会导致应用程序崩溃。。。我希望我的回答对你有帮助

Answer 2

把地震放进去（）；上方 mRequestQueue=截击。newRequestQueue（这个）

像这样

mRecycleView.setAdapter(adapter);
        adapter.notifyDataSetChanged();
        parseEarthquake();
        mRequestQueue = Volley.newRequestQueue(this);

如果你有工作，请分享你的错误