结对编码

要求：1.实现页面跳转（至少两个页面）

　　　2.使用多线程以及网络编程

功能：从网络获取新闻，并以列表的形式表现出来；当点击一条新闻时，此新闻可以在另一个页面打开，显示的是此新闻详情。

代码如下：

1.主界面的列表布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

2.主布局列表中所绑定适配器的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="150px"
        android:layout_height="105px"
        app:srcCompat="@mipmap/ic_launcher"
        android:id="@+id/item_pic" />

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:text="标题"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/item_title"
            android:textColor="#000000"
            android:textSize="14sp" />

        <LinearLayout
            android:orientation="horizontal"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <TextView
                android:text="来源"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/item_description"
                android:layout_weight="1" />

            <TextView
                android:text="时间"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/item_time"
                android:textAlignment="textEnd"
                android:layout_weight="1" />
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

3.显示新闻详情

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.demo.Activityweb">

    <WebView
        android:id="@+id/web"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

4.网络连接工具类

package com.example.demo;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Handler;
import android.os.Message;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * 网络连接工具类
 */

public class HttpUtil {
    //API的key--可以在百度API中获取
    public static final String APIKEY = "****************************";
    //获取新闻频道API
    public static final String GUONEI = "https://api.tianapi.com/tiyu/";
    public static final String surl = HttpUtil.GUONEI + "?key=" + HttpUtil.APIKEY + "&num=20";
    public static final int what = 1;

    /**
     * 获取连接和返回json数据
     *
     * @param handler
     */
    public void httpGetData_Get(final Handler handler) {

        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection httpURLConnection = null;
                try {
                    //创建URL对象
                    URL url = new URL(surl);
                    //返回一个URLConnection对象，它表示到URL所引用的远程对象链接
                    httpURLConnection = (HttpURLConnection) url.openConnection();
                    //设定请求方法，默认是GET方法
                    httpURLConnection.setRequestMethod("GET");
                    //设置连接超时时间
                    httpURLConnection.setConnectTimeout(30000);
                    //设置读取数据超时时间
                    httpURLConnection.setReadTimeout(5000);
                    //获取响应状态码
                    int responseCode = httpURLConnection.getResponseCode();
                    if (responseCode == 200) {
                        //定义一个输入流，获取服务器返回的数据
                        InputStream is = httpURLConnection.getInputStream();
                        InputStreamReader isr = new InputStreamReader(is);
                        BufferedReader br = new BufferedReader(isr);
                        //逐行遍历
                        String request = "";
                        String response = "";

                        while ((request = br.readLine()) != null) {
                            response += request;
                            Message msg = new Message();
                            msg.what = what;
                            msg.obj = response;
                            handler.sendMessage(msg);
                        }
                        br.close();
                        isr.close();
                        is.close();
                    }
                } catch (IOException e) {

                    e.printStackTrace();
                } finally {
                    if (httpURLConnection != null) {
                        httpURLConnection.disconnect();
                    }
                }
            }
        }).start();
    }

    /**
     * 图片的下载返回Bitmap数据
     *
     * @param pic_url 图片的URL
     * @param handler
     */
    public void getImgFromUrl(final String pic_url, final Handler handler) {

        new Thread() {
            @Override
            public void run() {
                super.run();
                HttpURLConnection httpURLConnection = null;
                try {
                    URL url = new URL(pic_url);
                    httpURLConnection = (HttpURLConnection) url.openConnection();
                    httpURLConnection.setRequestMethod("GET");
                    httpURLConnection.setReadTimeout(5000);
                    httpURLConnection.setConnectTimeout(10000);
                    int responseCode = httpURLConnection.getResponseCode();
                    if (responseCode == 200) {
                        //获取输入流
                        InputStream is = httpURLConnection.getInputStream();
                        //转换为Bitmap数据
                        Bitmap bitmap = BitmapFactory.decodeStream(is);

                        Message msg = new Message();
                        msg.what = 1;
                        msg.obj = bitmap;
                        handler.sendMessage(msg);
                        is.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    if (httpURLConnection != null) {
                        httpURLConnection.disconnect();
                    }
                }
            }
        }.start();
    }
}

5.主页面的逻辑代码

package com.example.demo;

import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

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

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity extends AppCompatActivity {
    List<Map<String, Object>> mapList;
    Adapter adapter;
    ListView lv;

    Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case 1:
                    //json解析
                    String response = msg.obj.toString();
                    try {
                        //解析json对象
                        JSONObject object = new JSONObject(response);
                        //解析json数组
                        JSONArray Array = object.getJSONArray("newslist");
                        //遍历
                        for (int i = 0; i < Array.length(); i++) {
                            Map<String, Object> map = new HashMap<>();
                            String ctime = Array.getJSONObject(i).getString("ctime");
                            String title = Array.getJSONObject(i).getString("title");
                            String description = Array.getJSONObject(i).getString("description");
                            String url = Array.getJSONObject(i).getString("url");
                            String picUrl = Array.getJSONObject(i).getString("picUrl");
                            map.put("ctime", ctime);
                            map.put("title", title);
                            map.put("description", description);
                            map.put("url", url);
                            map.put("picUrl", picUrl);
                            //将解析出来的数据存入数组
                            mapList.add(map);
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                    //将listview适配器存入数据
                    adapter = new Adapter(MainActivity.this, mapList);
                    lv = (ListView) findViewById(R.id.list);
                    lv.setAdapter(adapter);
                    //listview的监听
                    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                            //获取mapList里新闻详情的URL地址,并将地址通过intent传到Activityweb中打开
                            Intent intent = new Intent(MainActivity.this, Activityweb.class);
                            intent.putExtra("URL", mapList.get(i).get("url").toString());
                            intent.putExtra("description", mapList.get(i).get("description").toString());
                            startActivityForResult(intent, 1001);

                        }
                    });
                    break;
            }
        }
    };


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mapList = new ArrayList<>();
        //打开网络连接
        HttpUtil h = new HttpUtil();
        h.httpGetData_Get(handler);

    }

    /**
     * listview适配器
     */
    class Adapter extends BaseAdapter {
        List<Map<String, Object>> list;
        Context context;
        LayoutInflater layout;

        Adapter(Context context, List<Map<String, Object>> list) {
            this.context = context;
            layout = LayoutInflater.from(context);
            this.list = list;
        }

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

        @Override
        public Object getItem(int i) {
            return null;
        }

        @Override
        public long getItemId(int i) {
            return 0;
        }

        @Override
        public View getView(int i, View v, ViewGroup viewGroup) {
            final Items items = new Items();
            v = layout.inflate(R.layout.item, null);
            items.title = (TextView) v.findViewById(R.id.item_title);
            items.description = (TextView) v.findViewById(R.id.item_description);
            items.time = (TextView) v.findViewById(R.id.item_time);
            items.pic = (ImageView) v.findViewById(R.id.item_pic);

            //给item里面的控件赋值
            items.title.setText(mapList.get(i).get("title").toString());
            items.description.setText(mapList.get(i).get("description").toString());
            items.time.setText(mapList.get(i).get("ctime").toString());

            Handler pic = new Handler() {
                @Override
                public void handleMessage(Message msg) {
                    super.handleMessage(msg);
                    if (msg.what == 1) {
                        //将Bitmap的数据赋给imageview
                        Bitmap bitmap = (Bitmap) msg.obj;
                        items.pic.setImageBitmap(bitmap);
                    }
                }
            };
            //打开网络连接获取图片
            HttpUtil h = new HttpUtil();
            h.getImgFromUrl(mapList.get(i).get("picUrl").toString(), pic);
            return v;
        }

        class Items {
            ImageView pic;
            TextView title;
            TextView description;
            TextView time;
        }
    }
}

6.web页面的逻辑代码--用于显示新闻详情

package com.example.demo;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;

public class Activityweb extends AppCompatActivity {

    private WebView webview;

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

        //获取MainActivity传过来的网址
        Intent i = getIntent();
        String URL = i.getStringExtra("URL");
        String description = i.getStringExtra("description");
        setTitle(description);

        webview = (WebView) findViewById(R.id.web);
        //设置WebView属性，能够执行Javascript脚本
        webview.getSettings().setJavaScriptEnabled(true);
        //加载需要显示的网页
        webview.loadUrl(URL);
        //禁用缓存
        webview.getSettings().setCacheMode(WebSettings.LOAD_NO_CACHE);
        //设置Web视图,而不是打开系统应用
        webview.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
        });

    }

}

7.最后不要忘记在AndriodMainfest文件中添加网络权限声明：

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

8.运行截图