简易新闻客户端案例

运行界面如下：

实现这个案例需要在project视图下的app文件夹下的libs文件夹下导入三个包，如下图所示：

(1)首先我们在main_activity布局文件中创建以下代码：

<?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=".MainActivity"    android:orientation="vertical">    <FrameLayout        android:layout_width="match_parent"        android:layout_height="match_parent">        <LinearLayout            android:id="@+id/loading"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:gravity="center"            android:orientation="vertical"            android:visibility="invisible">            <ProgressBar                android:layout_width="wrap_content"                android:layout_height="wrap_content" />            <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:text="正在加载信息..." />        </LinearLayout>        <ListView            android:id="@+id/lv_news"            android:layout_width="match_parent"            android:layout_height="match_parent" />    </FrameLayout></LinearLayout>

(2)创建List View布局,Item.xml文件如下：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="65dp">    <com.loopj.android.image.SmartImageView        android:id="@+id/siv_icon"        android:layout_width="80dp"        android:layout_height="60dp"        android:scaleType="centerCrop"        android:src="@mipmap/ic_launcher"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true">    </com.loopj.android.image.SmartImageView>    <TextView        android:id="@+id/tv_title"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_marginLeft="5dp"        android:layout_marginTop="10dp"        android:layout_toRightOf="@id/siv_icon"        android:ellipsize="end"        android:maxLength="20"        android:singleLine="true"        android:text="我是标题"        android:textColor="#000000"        android:textSize="18sp" />    <TextView        android:id="@+id/tv_description"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@id/tv_title"        android:layout_marginLeft="5dp"        android:layout_marginTop="5dp"        android:layout_toRightOf="@id/siv_icon"        android:ellipsize="end"        android:maxLength="16"        android:maxLines="1"        android:text="我是描述"        android:textColor="#99000000"        android:textSize="14sp" />    <TextView        android:id="@+id/tv_type"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_alignParentRight="true"        android:layout_marginBottom="5dp"        android:layout_marginRight="10dp"        android:text="评论"        android:textColor="#99000000"        android:textSize="12sp" /></RelativeLayout>

(3)创建一个entity文件夹存放News Info类

package com.example.bz0209.news.entity;/** * Created by Administrator on 2017/5/18. */public class NewsInfo {    private String iconPath;    private String title;    public String getDescription() {        return description;    }    public void setDescription(String description) {        this.description = description;    }    public String getIconPath() {        return iconPath;    }    public void setIconPath(String iconPath) {        this.iconPath = iconPath;    }    public String getTitle() {        return title;    }    public void setTitle(String title) {        this.title = title;    }    public long getComment() {        return comment;    }    public void setComment(long comment) {        this.comment = comment;    }    public int getType() {        return type;    }    public void setType(int type) {        this.type = type;    }    private String description;    private int type;    private long comment;}

(4)编写工具类NewsInfoService解析XML文件得到List对象，并编写config.xml获取serverurl的值
NewsInfoService代码如下：

package com.example.bz0209.news.dao;import android.util.Xml;import com.example.bz0209.news.entity.NewsInfo;import org.xmlpull.v1.XmlPullParser;import java.io.InputStream;import java.util.ArrayList;import java.util.List;/** * Created by Administrator on 2017/5/22. */public class NewsInfoService {    public static List<NewsInfo> getNewsInfos(InputStream is){        XmlPullParser parser= Xml.newPullParser();        try{            parser.setInput(is,"utf-8");            int type=parser.getEventType();            List<NewsInfo> newsInfos=null;            NewsInfo newsInfo=null;            while (type!=XmlPullParser.END_DOCUMENT){                switch (type){                    case XmlPullParser.START_TAG:                        if("news".equals(parser.getName())){                            newsInfos=new ArrayList<NewsInfo>();                        }else if("newsInfo".equals(parser.getName())){                            newsInfo=new NewsInfo();                        }else if("icon".equals(parser.getName())){                            String icon=parser.nextText();                            newsInfo.setIconPath(icon);                        }else if("title".equals(parser.getName())){                            String title=parser.nextText();                            newsInfo.setTitle(title);                        }else if("content".equals(parser.getName())){                            String description=parser.nextText();                            newsInfo.setDescription(description);                        }else if("type".equals(parser.getName())){                            String newsType=parser.nextText();                            newsInfo.setType(Integer.parseInt(newsType));                        }else if("comment".equals(parser.getName())){                            String comment=parser.nextText();                            newsInfo.setComment(Long.parseLong(comment));                        }                        break;            }                type=parser.next();            }            return newsInfos;        }catch(Exception e){            e.printStackTrace();            return null;        }    }}

config.xml文件代码如下

<?xml version="1.0" encoding="utf-8"?><resources>    <string name="serverurl">http://10.51.30.166:8080/newInfo.xml</string></resources>

(5)编写用户交互代码，并进行List View的适配器编码，并用AysncHttpClient获取服务器的Xml文件

package com.example.bz0209.news;import android.graphics.Color;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.view.ViewParent;import android.widget.BaseAdapter;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.TextView;import android.widget.Toast;import cz.msebera.android.httpclient.Header;import com.example.bz0209.news.dao.NewsInfoService;import com.example.bz0209.news.entity.NewsInfo;import com.loopj.android.http.AsyncHttpClient;import com.loopj.android.http.AsyncHttpResponseHandler;import com.loopj.android.image.SmartImageView;import java.io.ByteArrayInputStream;import java.util.List;import java.util.Objects;import static android.R.id.content;public class MainActivity extends AppCompatActivity {    private ListView lv_news;    private LinearLayout loading;    private List<NewsInfo> newsInfos;    private class NewsAdapter extends BaseAdapter{        public int getCount(){            return newsInfos.size();        }        @Override        public View getView(int i, View view, ViewGroup viewGroup) {            return null;        }        public View getView(int position, View convertView, ViewParent parent){            View view=View.inflate(MainActivity.this,R.layout.item,null);            SmartImageView siv= (SmartImageView) view.findViewById(R.id.siv_icon);            TextView tv_title= (TextView) view.findViewById(R.id.tv_title);            TextView tv_description= (TextView) view.findViewById(R.id.tv_description);            TextView tv_type= (TextView) view.findViewById(R.id.tv_type);            NewsInfo newsInfo=newsInfos.get(position);            siv.setImageUrl(newsInfo.getIconPath(),R.drawable.a,R.drawable.ic_launcher);            tv_title.setText(newsInfo.getTitle());            tv_description.setText(newsInfo.getDescription());            tv_type.setText(newsInfo.getType());            int type=newsInfo.getType();            switch (type){                case 1:                    tv_type.setText("comment"+newsInfo.getComment());                    break;                case 2:                    tv_type.setTextColor(Color.RED);                    tv_type.setText("headline");                    break;                case 3:                    tv_type.setTextColor(Color.BLUE);                    tv_type.setText("LIVE");                    break;            }            return view;        }        public Object getItem(int position){            return null;        }        public long getItemId(int position){            return 0;        }    }    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        lv_news=(ListView)findViewById(R.id.lv_news);        loading=(LinearLayout)findViewById(R.id.loading);        fillData2();    }    private void fillData2(){        AsyncHttpClient asyncHttpClient=new AsyncHttpClient();        asyncHttpClient.get(getString(R.string.serverurl), new AsyncHttpResponseHandler() {            @Override            public void onSuccess(String content) {                super.onSuccess(content);                byte[] bytes=content.getBytes();                ByteArrayInputStream bs=new ByteArrayInputStream(bytes);                newsInfos= NewsInfoService.getNewsInfos(bs);                if(newsInfos==null){                    Toast.makeText(MainActivity.this,"fail",Toast.LENGTH_LONG).show();                }else{                    loading.setVisibility(View.INVISIBLE);                    lv_news.setAdapter(new NewsAdapter());                }            }            @Override            public void onFailure(Throwable error,String content) {                super.onFailure(error,content);                Toast.makeText(MainActivity.this, "request fail", Toast.LENGTH_SHORT).show();            }        });    }}

(6).配置服务器，先开启服务器并运行start.bat。把要解析的xml文件放入到tomcat的bin文件夹下的web apps的root文件夹下

(7)在清单文件中添加权限

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.example.bz0209.news">    <application        android:allowBackup="true"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application><uses-permission android:name="android.permission.INTERNET"/></manifest>