需要，也需要完整的代码

好的，下面是具体的实现步骤和代码：

1.首先，在AndroidManifest.xml文件中添加以下权限：

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

2.然后在build.gradle文件中添加以下依赖：

implementation 'com.squareup.okhttp3:okhttp:3.12.0'

3.在Activity中定义ListView和OkHttpClient对象：

private ListView listView;
private OkHttpClient client;

4.在onCreate()方法中初始化ListView和OkHttpClient对象：

listView = findViewById(R.id.list_view);
client = new OkHttpClient();

5.然后定义一个方法来请求数据并展示到ListView中：

private void requestData() {
    //创建一个Request对象
    Request request = new Request.Builder()
            .url("http://xxx.xxx.xxx.xxx/api/news")
            .build();
    //发送请求并处理响应
    client.newCall(request).enqueue(new Callback() {
        @Override
        public void onFailure(Call call, IOException e) {
            e.printStackTrace();
        }

        @Override
        public void onResponse(Call call, Response response) throws IOException {
            final String responseData = response.body().string();
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    //解析数据并展示到ListView中
                    List<News> newsList = parseData(responseData);
                    NewsAdapter adapter = new NewsAdapter(MainActivity.this, newsList);
                    listView.setAdapter(adapter);
                    //ListView的单击事件
                    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                            //跳转到详情页面
                            Intent intent = new Intent(MainActivity.this, DetailActivity.class);
                            intent.putExtra("news", newsList.get(position));
                            startActivity(intent);
                        }
                    });
                }
            });
        }
    });
}

6.然后定义一个News类来封装新闻数据：

public class News {
    private String title;
    private String content;
    //其他属性

    //getter和setter方法

    @Override
    public String toString() {
        return "News{" +
                "title='" + title + '\'' +
                ", content='" + content + '\'' +
                //其他属性
                '}';
    }
}

7.然后定义一个NewsAdapter类来为ListView提供数据：

public class NewsAdapter extends BaseAdapter {
    private Context context;
    private List<News> newsList;

    public NewsAdapter(Context context, List<News> newsList) {
        this.context = context;
        this.newsList = newsList;
    }

    @Override
    public int getCount() {
        return newsList.size();
    }

    @Override
    public Object getItem(int position) {
        return newsList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = LayoutInflater.from(context).inflate(R.layout.item_news, parent, false);
            holder = new ViewHolder();
            holder.titleTextView = convertView.findViewById(R.id.title_text_view);
            holder.contentTextView = convertView.findViewById(R.id.content_text_view);
            //其他控件
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        //设置数据
        News news = newsList.get(position);
        holder.titleTextView.setText(news.getTitle());
        holder.contentTextView.setText(news.getContent());
        //其他数据
        return convertView;
    }

    private static class ViewHolder {
        TextView titleTextView;
        TextView contentTextView;
        //其他控件
    }
}

8.最后在Activity中调用requestData()方法来请求数据并展示到ListView中：

requestData();

以上就是实现新闻界面展示的步骤和代码，其中一些细节可能需要你自己根据实际情况进行调整。