如何在ListView解析News API的title，点击后跳转展示对应description？

Hey there! Let's build this feature for your Android app step by step. First, let's take a look at the sample JSON response from the news.org API you provided:

Sample JSON Response

[
  {
    "source": { "id": "the-hindu", "name": "The Hindu" },
    "author": "",
    "title": "Questionable remedy: on the National Medical Commission Bill",
    "description": "Key sections of the National Medical Commission Bill need a rethink",
    "url": "http://www.thehindu.com/opinion/editorial/questionable-remedy/article22354009.ece",
    "urlToImage": "http://www.thehindu.com/static/theme/default/base/img/og-image.jpg",
    "publishedAt": null
  },
  {
    "source": { "id": "the-hindu", "name": "The Hindu" },
    "author": "",
    "title": "On the ledger: on fiscal consolidation",
    "description": "Expenditure data underline the government’s challenge on fiscal consolidation",
    "url": "http://www.thehindu.com/opinion/editorial/on-the-ledger/article22354014.ece",
    "urlToImage": "http://www.thehindu.com/static/theme/default/base/img/og-image.jpg",
    "publishedAt": null
  }
]

Step 1: Create a News Model Class #

We need a model to map the JSON data to Java objects. We'll use Gson for easy parsing, so first add this dependency to your module-level build.gradle:

implementation 'com.google.code.gson:gson:2.10.1'

Now create the News class:

public class News {
    private Source source;
    private String author;
    private String title;
    private String description;
    private String url;
    private String urlToImage;
    private String publishedAt;

    // Getters for fields we need
    public String getTitle() {
        return title;
    }

    public String getDescription() {
        return description;
    }

    // Inner class to map the "source" object
    public static class Source {
        private String id;
        private String name;
        // Add getters here if you need to use source data later
    }
}

Step 2: Fetch and Parse API Data #

Let's use Volley for simple network requests. Add this dependency first:

implementation 'com.android.volley:volley:1.2.1'

In your main Activity, fetch the API data and parse it into a list of News objects:

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.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Type;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    private ListView newsListView;
    private List<News> newsList;
    private NewsAdapter adapter;

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

        newsListView = findViewById(R.id.news_list_view);
        RequestQueue queue = Volley.newRequestQueue(this);
        String apiUrl = "YOUR_NEWS_ORG_API_ENDPOINT"; // Replace with your actual API URL

        JsonArrayRequest jsonRequest = new JsonArrayRequest(Request.Method.GET, apiUrl, null,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        // Parse JSON array to List<News>
                        Gson gson = new Gson();
                        Type newsListType = new TypeToken<List<News>>(){}.getType();
                        newsList = gson.fromJson(response.toString(), newsListType);

                        // Set up adapter for ListView
                        adapter = new NewsAdapter(MainActivity.this, newsList);
                        newsListView.setAdapter(adapter);
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Toast.makeText(MainActivity.this, "Failed to load news", Toast.LENGTH_SHORT).show();
            }
        });

        queue.add(jsonRequest);
    }
}

Step 3: Build a Custom ListView Adapter #

First, create a layout for each list item (layout_list_item.xml):

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/news_title_tv"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp"
    android:textSize="18sp"
    android:textColor="@android:color/black"/>

Then create the NewsAdapter class to populate the ListView:

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.List;

public class NewsAdapter extends ArrayAdapter<News> {
    public NewsAdapter(Context context, List<News> newsItems) {
        super(context, 0, newsItems);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        News currentNews = getItem(position);

        // Reuse existing view if available
        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.layout_list_item, parent, false);
        }

        // Set title to the TextView
        TextView titleTv = convertView.findViewById(R.id.news_title_tv);
        titleTv.setText(currentNews.getTitle());

        return convertView;
    }
}

Step 4: Handle Item Clicks for Navigation #

Add a click listener to the ListView in MainActivity's onCreate method (right after setting the adapter):

newsListView.setOnItemClickListener((parent, view, position, id) -> {
    News selectedNews = newsList.get(position);
    Intent intent = new Intent(MainActivity.this, DescriptionActivity.class);
    intent.putExtra("NEWS_DESCRIPTION", selectedNews.getDescription());
    startActivity(intent);
});

Step 5: Create the Description Activity #

First, make the layout (activity_description.xml):

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="16dp">

    <TextView
        android:id="@+id/description_tv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="16sp"/>

</ScrollView>

Then create the DescriptionActivity class to display the description:

import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class DescriptionActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_description);

        TextView descriptionTv = findViewById(R.id.description_tv);
        Intent incomingIntent = getIntent();

        if (incomingIntent != null && incomingIntent.hasExtra("NEWS_DESCRIPTION")) {
            String description = incomingIntent.getStringExtra("NEWS_DESCRIPTION");
            descriptionTv.setText(description);
        }
    }
}

Don't forget to register this activity in your AndroidManifest.xml:

<activity android:name=".DescriptionActivity"/>

内容的提问来源于stack exchange，提问作者harkirat singh