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本文实例为大家分享了Android新闻浏览客户端,基于php后台,供大家参考,具体内容如下
1、使用HBuilder进行PHP环境配置,测试是否可以查询MySQL语句,之前都已经详细说明过了。
2、此处php后台实现mysql的查询功能,并以JSON数据格式返回个客户端
在PHP此处建立一个mysql_connect.php文件,实现数据库的连接,并设置字符集格式。
<"localhost","root","123456"); //设置字符集为UTF-8 可解决中文乱码 mysql_query("SET NAMES 'utf8'"); mysql_query("SET CHARACTER SET utf8"); mysql_query("SET CHARACTER_SET_RESULT=utf8"); if(!$con){ die(mysql_error()); } mysql_select_db("newsdemo",$con); "htmlcode"><"select * from news"); while($row = mysql_fetch_array($result)){ $arr[$n++] = array( "title"=>$row['title'], "desc"=>$row['desc'], "time"=>$row['time'], "content_url"=>$row['content_url'], "pic_url"=>$row['pic_url'] ); } //数组转化为JSON字符串 echo json_encode($arr); "htmlcode">public class MainActivity extends Activity implements OnItemClickListener{ private ListView lvNews ; private NewsAdapter adapter ; //定义集合 private List<News> newsList ; //获取json字符串的URL地址 public static final String GET_NEWS_URL = "http://211.87.234.20/NewsDemo/getNewsJSON.php"; //获取msg之后如何处理 private Handler getNewsHandler = new Handler(){ public void handleMessage(android.os.Message msg){ String jsonData = (String) msg.obj ; System.out.println(jsonData) ; try { JSONArray jsonArray = new JSONArray(jsonData) ; for(int i=0;i<jsonArray.length();i++){ JSONObject object = jsonArray.getJSONObject(i) ; String title = object.getString("title") ; String desc = object.getString("desc") ; String time = object.getString("time") ; String content_url = object.getString("content_url") ; String pic_url = object.getString("pic_url") ; System.out.println("title="+title) ; //add一个News类型的Object newsList.add(new News(title,desc,time,content_url,pic_url)) ; } //通知更新 adapter.notifyDataSetChanged() ; } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } ; } ; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState) ; setContentView(R.layout.activity_main) ; lvNews = (ListView) findViewById(R.id.lvNews) ; //初始化 newsList = new ArrayList<News>(); adapter = new NewsAdapter(this,newsList) ; lvNews.setAdapter(adapter) ; lvNews.setOnItemClickListener(this) ; HttpUtils.getNewsJSON(GET_NEWS_URL,getNewsHandler) ; } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public void onItemClick(AdapterView<"content_url",news.getContent_url()) ; startActivity(intent) ; } }此处需要一个工具类HttpUtils以及自定义的NewsAdapter以实现item的视图显示.
HttpUtils代码如下:
package com.MR.news.utils; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Handler; import android.os.Message; import android.widget.ImageView; public class HttpUtils { //工具类直接定义成静态方法即可 /*url用于内部类中,所以要将其设定为final类型*/ /*读取完成需要通知主线程,需要使用handler*/ public static void getNewsJSON(final String url,final Handler handler){ //访问网络,时间长,开启新线程 new Thread(new Runnable(){ @Override public void run() { // TODO Auto-generated method stub HttpURLConnection conn ; InputStream is ; try { conn = (HttpURLConnection) new URL(url).openConnection() ; //GET方式获取 conn.setRequestMethod("GET") ; //得到输入流 is=conn.getInputStream() ; //读取数据用缓冲,里面要传入一个reader BufferedReader reader = new BufferedReader(new InputStreamReader(is)); //一行一行读取数据 String line = ""; //没读完一行进行拼接,高效 StringBuilder result = new StringBuilder(); while((line = reader.readLine()) != null){ result.append(line); } Message msg = new Message() ; //msg.obj可以放进去任何对象 msg.obj = result.toString() ; handler.sendMessage(msg) ; } catch (Exception e) { e.printStackTrace(); } }}).start() ; } public static void setPicBitMap(final ImageView ivPic,final String pic_url){ new Thread(new Runnable(){ @Override public void run() { // TODO Auto-generated method stub try { HttpURLConnection conn = (HttpURLConnection) new URL(pic_url).openConnection() ; conn.connect() ; InputStream is = conn.getInputStream() ; //bitmap就是所需图片资源 /*从资源文件中的到图片*/ Bitmap bitmap = BitmapFactory.decodeStream(is) ; ivPic.setImageBitmap(bitmap) ; is.close() ; } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } }).start() ; } }NewsAdapter代码如下:
package com.MR.news.adapter; import java.util.List; import com.MR.news.R; import com.MR.news.model.News; import com.MR.news.utils.HttpUtils; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; public class NewsAdapter extends BaseAdapter { //声明上下文对象,后面的getView方法需要 private Context context; private List<News> newsList; public NewsAdapter(Context context, List<News> newsList){ this.context = context ; this.newsList = newsList ; } @Override public int getCount() { // TODO Auto-generated method stub return newsList.size(); } @Override public Object getItem(int position) { // TODO Auto-generated method stub return newsList.get(position); } @Override public long getItemId(int position) { // TODO Auto-generated method stub return position; } @Override public View getView(int position, View convertView, ViewGroup arg2) { // TODO Auto-generated method stub if(convertView == null){ convertView = LayoutInflater.from(context).inflate(R.layout.news_item,null) ; } TextView tvTitle = (TextView) convertView.findViewById(R.id.tvTitle) ; TextView tvDesc = (TextView) convertView.findViewById(R.id.tvDesc) ; TextView tvTime = (TextView) convertView.findViewById(R.id.tvTime) ; ImageView ivPic = (ImageView) convertView.findViewById(R.id.ivPic); News news = newsList.get(position) ; tvTitle.setText(news.getTitle()) ; tvDesc.setText(news.getDesc()) ; tvTime.setText(news.getTime()) ; String pic_url = news.getPic_url() ; HttpUtils.setPicBitMap(ivPic, pic_url) ; return convertView; } }news_item用来设置每个item的显示格式
<"1.0" encoding="utf-8""http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > <ImageView android:id="@+id/ivPic" android:layout_width="42dp" android:layout_height="42dp" android:src="/UploadFiles/2021-04-02/ic_launcher">注意:此item中需要显示单个图片,所以用到Bitmap这个类。由于用到网络传输,所以需要用到线程这个概念!!
关键理解handler message以及loop这三者的关系。
以上就是本文的全部内容,希望对大家学习Android软件编程有所帮助。
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