从 newsapi.org 获取新闻 api 时出错

Question

I am making News App using Newsapi.org API key I have written all the code and compiled successfully but app is not fetching any data through that key.

---

This is my MainActivity.java file

    package com.example.newsindia;

import androidx.appcompat.app.AppCompatActivity;

import android.app.LoaderManager;
import android.content.Context;
import android.content.Intent;
import android.content.Loader;
import android.content.SharedPreferences;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<List<News>> {
    private NewsAdapter mAdapter;
    private TextView mEmptyStateTextView;
    private static final int EARTHQUAKE_LOADER_ID = 1;
    public static final String LOG_TAG = MainActivity.class.getName();
    private static final String NEWS_REQUEST_URL = "http://newsapi.org/v2/top-headlines?country=in&apiKey=7615387a23b04e68b9f2b79719d19786";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ListView newsListView = (ListView) findViewById(R.id.list);
        mAdapter=new NewsAdapter(this, new ArrayList<>());
        newsListView.setAdapter(mAdapter);
        mEmptyStateTextView = (TextView) findViewById(R.id.empty_view);
        newsListView.setEmptyView(mEmptyStateTextView);
        newsListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position, long l) {
                // Find the current earthquake that was clicked on
                News currentEarthquake = mAdapter.getItem(position);

                // Convert the String URL into a URI object (to pass into the Intent constructor)
                Uri earthquakeUri = Uri.parse(currentEarthquake.getmUrl());

                // Create a new intent to view the earthquake URI
                Intent websiteIntent = new Intent(Intent.ACTION_VIEW, earthquakeUri);

                // Send the intent to launch a new activity
                startActivity(websiteIntent);
            }
        });


        // Get a reference to the ConnectivityManager to check state of network connectivity
        ConnectivityManager connMgr = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);

        // Get details on the currently active default data network
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        // Start the AsyncTask to fetch the earthquake data

        if (networkInfo != null && networkInfo.isConnected()) {
            // Get a reference to the LoaderManager, in order to interact with loaders.
            LoaderManager loaderManager = getLoaderManager();

            // Initialize the loader. Pass in the int ID constant defined above and pass in null for
            // the bundle. Pass in this activity for the LoaderCallbacks parameter (which is valid
            // because this activity implements the LoaderCallbacks interface).
            loaderManager.initLoader(EARTHQUAKE_LOADER_ID, null, this);
        }
        else {
            // Otherwise, display error
            // First, hide loading indicator so error message will be visible
            View loadingIndicator = findViewById(R.id.loading_indicator);
            loadingIndicator.setVisibility(View.GONE);

            // Update empty state with no connection error message
            mEmptyStateTextView.setText(R.string.no_internet_connection);
        }
    }

    @Override
    public Loader<List<News>> onCreateLoader(int i, Bundle bundle) {




        Uri baseUri = Uri.parse(NEWS_REQUEST_URL);
        Uri.Builder uriBuilder = baseUri.buildUpon();

        uriBuilder.appendQueryParameter("format", "geojson");
        uriBuilder.appendQueryParameter("limit", "10");

        return new NewsLoader(this, uriBuilder.toString());
    }

    @Override
    public void onLoadFinished(Loader<List<News>> loader, List<News> earthquakes) {
        // Clear the adapter of previous earthquake data
        // Hide loading indicator because the data has been loaded
        View loadingIndicator = findViewById(R.id.loading_indicator);
        loadingIndicator.setVisibility(View.GONE);
        mAdapter.clear();

        // If there is a valid list of {@link Earthquake}s, then add them to the adapter's
        // data set. This will trigger the ListView to update.
        if (earthquakes != null && !earthquakes.isEmpty()) {
            mAdapter.addAll(earthquakes);
        }
        // Set empty state text to display "No earthquakes found."
        mEmptyStateTextView.setText(R.string.no_earthquakes);
    }

    @Override
    public void onLoaderReset(Loader<List<News>> loader) {
        // Loader reset, so we can clear out our existing data.
        mAdapter.clear();
    }


    }

---

This is my QuerUtils.java class

package com.example.newsindia;

import android.text.TextUtils;
import android.util.Log;

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

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import static com.example.newsindia.MainActivity.LOG_TAG;
import static java.lang.Long.parseLong;

public final class QueryUtils {
    private QueryUtils() {

    }
    public static long parseLong(String s)
    {
        long timeInMilliseconds = Long.parseLong(s);

        return timeInMilliseconds;
    }
    private static String formatTime(Date dateObject) {
        SimpleDateFormat timeFormat = new SimpleDateFormat("h:mm a");
        return timeFormat.format(dateObject);
    }

    /**
     * Return a list of {@link } objects that has been built up from
     * parsing the given JSON response.
     */
    private static List<News> extractFeatureFromJson(String earthquakeJSON) {
        if (TextUtils.isEmpty(earthquakeJSON)) {
            return null;
        }
        // Create an empty ArrayList that we can start adding earthquakes to
        // Create an empty ArrayList that we can start adding earthquakes to
        List<News> earthquakes = new ArrayList<>();

        // Try to parse the SAMPLE_JSON_RESPONSE. If there's a problem with the way the JSON
        // is formatted, a JSONException exception object will be thrown.
        // Catch the exception so the app doesn't crash, and print the error message to the logs.
        try {


            // build up a list of Earthquake objects with the corresponding data.
            JSONObject root= new JSONObject(earthquakeJSON);
            JSONArray earthquakeArray= root.getJSONArray("articles");
            for(int i =0;i<earthquakeArray.length();i++)
            {
                JSONObject currentEarthquake= earthquakeArray.getJSONObject(i);

                String title = currentEarthquake.getString("title");
                String description= currentEarthquake.getString("description");
                String image= currentEarthquake.getString("urlToImage");
                // Extract the value for the key called "url"
                String url = currentEarthquake.getString("url");
                String time=currentEarthquake.getString("publishedAt");

                long ans= parseLong(time);
                Date dateObject = new Date(ans);

                String timing= formatTime(dateObject);
                News earthQuakes = new News(title,description,image,timing,url);
                earthquakes.add(earthQuakes);
            }

        } 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);
        }

        // Return the list of earthquakes
        return earthquakes;
    }



    List<News> earthquakes = new ArrayList<>();
    private static URL createUrl(String stringUrl) {
        URL url = null;
        try {
            url = new URL(stringUrl);
        } catch (MalformedURLException e) {
            Log.e(LOG_TAG, "Problem building the URL ", e);
        }
        return url;
    }

    /**
     * Make an HTTP request to the given URL and return a String as the response.
     */
    private static String makeHttpRequest(URL url) throws IOException {
        String jsonResponse = "";

        // If the URL is null, then return early.
        if (url == null) {
            return jsonResponse;
        }

        HttpURLConnection urlConnection = null;
        InputStream inputStream = null;
        try {
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.setReadTimeout(10000 /* milliseconds */);
            urlConnection.setConnectTimeout(15000 /* milliseconds */);
            urlConnection.setRequestMethod("GET");
            urlConnection.connect();

            // If the request was successful (response code 200),
            // then read the input stream and parse the response.
            if (urlConnection.getResponseCode() == 200) {
                inputStream = urlConnection.getInputStream();
                jsonResponse = readFromStream(inputStream);
            } else {
                Log.e(LOG_TAG, "Error response code: " + urlConnection.getResponseCode());
            }
        } catch (IOException e) {
            Log.e(LOG_TAG, "Problem retrieving the earthquake JSON results.", e);
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (inputStream != null) {
                // Closing the input stream could throw an IOException, which is why
                // the makeHttpRequest(URL url) method signature specifies than an IOException
                // could be thrown.
                inputStream.close();
            }
        }
        return jsonResponse;
    }

    /**
     * Convert the {@link InputStream} into a String which contains the
     * whole JSON response from the server.
     */
    private static String readFromStream(InputStream inputStream) throws IOException {
        StringBuilder output = new StringBuilder();
        if (inputStream != null) {
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
            BufferedReader reader = new BufferedReader(inputStreamReader);
            String line = reader.readLine();
            while (line != null) {
                output.append(line);
                line = reader.readLine();
            }
        }
        return output.toString();
    }


    /**
     * Query the USGS dataset and return a list of {@link } objects.
     */
    public static List<News> fetchEarthquakeData(String requestUrl) {
        // Create URL object
        URL url = createUrl(requestUrl);

        // Perform HTTP request to the URL and receive a JSON response back
        String jsonResponse = null;
        try {
            jsonResponse = makeHttpRequest(url);
        } catch (IOException e) {
            Log.e(LOG_TAG, "Problem making the HTTP request.", e);
        }

        // Extract relevant fields from the JSON response and create a list of {@link Earthquake}s
        List<News> earthquakes = extractFeatureFromJson(jsonResponse);

        // Return the list of {@link Earthquake}s
        return earthquakes;
    }
}

I Have created 3 more java files ie NewsAdapter.java for displaying items with the help of listeview + Adapterview

2nd --> NewsLoader.java class to implement loader class

3rd--->News.java class which will return all the value from api like title,description,image,etc

Answer 1

Check this source code download it analyse it and see where you have done a mistake https://github.com/MohammedAbidNafi/News