失眠网 > android--新闻阅读器实现源码

android--新闻阅读器实现源码

时间：2020-05-08 11:34:21

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android--新闻阅读器实现源码

先看布局文件

MainActivity:

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android="/apk/res/android"xmlns:app="/apk/res-auto"xmlns:tools="/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><Buttonandroid:id="@+id/btnzg"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginStart="16dp"android:layout_marginTop="16dp"android:onClick="btn1"android:text="国内新闻"app:layout_constraintEnd_toStartOf="@+id/btnwg"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintHorizontal_chainStyle="packed"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" /><Buttonandroid:id="@+id/btnwg"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginStart="16dp"android:layout_marginTop="16dp"android:layout_marginEnd="16dp"android:onClick="btn2"android:text="国际新闻"app:layout_constraintEnd_toStartOf="@+id/btnjj"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/btnzg"app:layout_constraintTop_toTopOf="parent" /><Buttonandroid:id="@+id/btnjj"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginTop="16dp"android:layout_marginEnd="16dp"android:onClick="btn3"android:text="经济新闻"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/btnwg"app:layout_constraintTop_toTopOf="parent" /><ListViewandroid:id="@+id/lv"android:layout_width="0dp"android:layout_height="0dp"android:layout_marginStart="16dp"android:layout_marginTop="16dp"android:layout_marginEnd="16dp"android:layout_marginBottom="16dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/btnwg" /></android.support.constraint.ConstraintLayout>

在创建一个layout 布局页面

<?xml version="1.0" encoding="utf-8"?><android.support.constraint.ConstraintLayout xmlns:android="/apk/res/android"xmlns:app="/apk/res-auto"xmlns:tools="/tools"android:id="@+id/linearLayout"android:layout_width="match_parent"android:layout_height="wrap_content"><TextViewandroid:id="@+id/txt_count"android:layout_width="0dp"android:layout_height="64dp"android:layout_marginStart="16dp"android:layout_marginTop="16dp"android:layout_marginEnd="16dp"android:text="TextView"android:textSize="24sp"android:textStyle="bold"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent" /><TextViewandroid:id="@+id/txt_author"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginStart="32dp"android:layout_marginTop="16dp"android:layout_marginBottom="16dp"android:text="TextView"android:textSize="18sp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toStartOf="@+id/txt_Date"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/txt_count" /><TextViewandroid:id="@+id/txt_Date"android:layout_width="0dp"android:layout_height="wrap_content"android:layout_marginStart="16dp"android:layout_marginEnd="32dp"android:text="TextView"android:textAlignment="textEnd"android:textSize="18sp"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.5"app:layout_constraintStart_toEndOf="@+id/txt_author"app:layout_constraintTop_toTopOf="@+id/txt_author" /></android.support.constraint.ConstraintLayout>

创建news 新闻对象

用来放读取到的每一条新闻

package com.weilaikeji.newsread;/*** Created by hxp on /5/10.*/public class news {//建立新闻xml里面所需要的字段 private String title;private String link;private String pubDate;private String author;private String description;public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public String getLink() {return link;}public void setLink(String link) {this.link = link;}public String getPubDate() {return pubDate;}public void setPubDate(String pubDate) {this.pubDate = pubDate;}public String getAuthor() {return author;}public void setAuthor(String author) {this.author = author;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}@Overridepublic String toString() {return "news{" +"title='" + title + '\'' +", link='" + link + '\'' +", pubDate='" + pubDate + '\'' +", author='" + author + '\'' +", description='" + description + '\'' +'}';}}

创建 xmlPull()解析方法用来解析下载的xml

package com.weilaikeji.newsread;import android.util.Xml;import org.xmlpull.v1.XmlPullParser;import java.io.InputStream;import java.util.ArrayList;import java.util.List;public class NewsPull {public static List<news> getNews(InputStream is)throws Throwable{//创建一个list集合类型的getNews方法，使方法最终返回一个新闻类型的list 集合给一个输入流的参数List<news> news = null;news mnews = null;//创建XMLPullParserXmlPullParser parser = Xml.newPullParser();//解析文件输入流parser.setInput(is,"UTF-8");int eventType = parser.getEventType();while(eventType!=XmlPullParser.END_DOCUMENT){switch(eventType){case XmlPullParser.START_DOCUMENT://解析开始的时候初始化listnews = new ArrayList<>();break;case XmlPullParser.START_TAG://获得当前指向元素的名字//当指向元素的名字和title，link，author，description 这些属性重合时可以返回他们的值String xpptiele = parser.getName();if("item".equals(parser.getName())){//判断开始标签元素是否是itemmnews = new news();mnews.getTitle();}if(mnews!=null){if("title".equals(xpptiele)){mnews.setTitle(parser.nextText());}if("link".equals(xpptiele)){mnews.setLink(parser.nextText());}if("author".equals(xpptiele)){mnews.setAuthor(parser.nextText());}if("description".equals(xpptiele)){mnews.setDescription(parser.nextText());}if("pubDate".equals(xpptiele)){mnews.setPubDate(parser.nextText());}}break;//出发结束元素事件case XmlPullParser.END_TAG://判断开始标签元素是否是itemif("item".equals(parser.getName())){news.add(mnews);mnews = null;}break;default:break;}eventType = parser.next();}return news;}}

在MainActivity中

package com.weilaikeji.newsread;import android.content.Context;import android.os.Handler;import android.os.Message;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.ListView;import android.widget.SimpleAdapter;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.InputStream;import .HttpURLConnection;import .URL;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class MainActivity extends AppCompatActivity {ListView lvs;Map<String,Object> map3;List<Map<String,Object>> itmes = new ArrayList<>();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);btn();}//定义按钮方法点击那个按钮获得选中的url 赋值给download()方法public static String url ;public void btn( ){//国内新闻(默认显示)itmes.clear();url="/rss/politics.xml";download();};public void btn1(View view){//国内新闻itmes.clear();url="/rss/politics.xml";download();};public void btn2(View view){//体育新闻itmes.clear();url="/rss/sports.xml";download();//"/rss/haixia.xml"};public void btn3(View view){//台湾新闻itmes.clear();url="/rss/haixia.xml";download();};Handler handler = new Handler(){//创建一个Android消息处理机制重写handleMessage方法@Overridepublic void handleMessage(Message msg) {//处理消息的方法,使用handleMessage去处理消息，里面的参数Message//message对象可以接受任何类型的对象并且可以通过反向强制转换转换回来String title = ((news)msg.obj).getTitle();String pubDate = ((news)msg.obj).getPubDate();String author = ((news)msg.obj).getAuthor();String description = ((news)msg.obj).getDescription();map3 = new HashMap<>();//创建map 对象进行复制传递map3.put("title",title);map3.put("pubDate",pubDate);map3.put("author",author);map3.put("description",description);itmes.add(map3); //将map对象放进 list集合里面lvs = MainActivity.this.findViewById(R.id.lv); //获取ListView控件lvs.setAdapter(new SimpleAdapter(MainActivity.this,itmes,R.layout.lv2,new String[]{"title","pubDate","author"},new int[]{R.id.txt_count,R.id.txt_Date,R.id.txt_author}));}};//创建一个下载文件的方法public void download(){//创建一个工作线程，继承 Thread，重新 run 方法，处理耗时操作new Thread(){//创建子线程引文下载进程是一个缓慢的程序，主线线程不可以使用//重写run()方法。@Overridepublic void run() {try {Context context = MainActivity.this.getApplication(); //获取一个Context对象String path =context.getFilesDir()+"/test.xml"; //目的为了获得安卓的file目录String url1 = url;//创建下载连接URL url = new URL(url1); //创建一个URLHttpURLConnection con = (HttpURLConnection)url.openConnection();//获得一个HttpURLConnection对象 concon.setConnectTimeout(3*1000);//防止屏蔽程序抓取而返回403错误con.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");InputStream iso = con.getInputStream(); //通过con 获得一个输入流 iso 对象File file = new File(path); //创建一个file对象将路径写入FileOutputStream fos = new FileOutputStream(file);byte[] b = new byte[1024];int count = 0;while((count = iso.read(b,0,1024))!= -1){fos.write(b,0,count);System.out.print(b+"/kb");}fos.close();iso.close();List<news> pull = Pull(); //调用Pull()解析方法解析xml文件并返回List<news> 对象for(news n : pull){//遍历list集合Message msg = new Message(); //创建一个 Message 对象 Mmsg.obj=n; //message对象可以接受任何类型的对象并且可以通过反向强制转换转换回来handler.sendMessage(msg);}}catch (Exception e){System.out.println(e.getMessage());}}}.start();}public List<news> Pull(){try {Context context = MainActivity.this.getApplication();String url = context.getFilesDir()+"/test.xml";InputStream fis = new FileInputStream(url);List<news> list=NewsPull.getNews(fis);for (news n:list){System.out.println(n);}return list;} catch (Exception e) {e.printStackTrace();return null;} catch (Throwable throwable) {throwable.printStackTrace();return null;}}}

最后添加上权限：

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