创建一个新闻客户端

 

根据要求完成上图所示的界面

1.activity_main.xml文件如下：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:Android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"
   android:layout_width="match_parent"    android:layout_height="match_parent"
   tools:context="cn.edu.bzu.anew.MainActivity">

 

    <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>

</RelativeLayout>

 

news_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>

 

2.新建一个名为adapter的包名，新建一个NewsAdapter的类，内容如下：

 

package cn.edu.bzu.anew.adapter;import android.content.Context;import android.support.annotation.NonNull;importandroid.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;importandroid.widget.ArrayAdapter;import android.widget.TextView;import com.loopj.android.image.SmartImageView;importJava.util.List;import cn.edu.bzu.anew.R;import cn.edu.bzu.anew.entity.NewsInfo;

public class NewsAdapter extends ArrayAdapter<NewsInfo>{

    public NewsAdapter(Context context, List<NewsInfo> objects) {

        super(context, R.layout.news_item,
objects);

 

    }

 

    @NonNull    @Override    public View
getView(int position, View convertView, ViewGroup parent) {

        NewsInfo newsinfo= getItem(position);//传递position，获取当前位置对应的newsinfo新闻信息        View view=null;

        viewHolder viewHolder;

        if(convertView==null){ //判断convertView中是否加载了布局，有没有缓存。为空说明没有缓存
           view=LayoutInflater.from(getContext()).inflate(R.layout.news_item,null);

            viewHolder=new viewHolder();

            viewHolder.siv= (SmartImageView) view.findViewById(R.id.siv_icon);

            viewHolder.tv_title= (TextView) view.findViewById(R.id.tv_title);

            viewHolder.tv_description= (TextView) view.findViewById(R.id.tv_description);

            viewHolder.tv_type= (TextView) view.findViewById(R.id.tv_type);

            view.setTag(viewHolder); //保存        }else{

            view=convertView;

            viewHolder=(viewHolder) view.getTag();

        }

        viewHolder.siv.setImageUrl(newsinfo.getIcon());

        viewHolder.tv_title.setText(newsinfo.getTitle());//传递题目        viewHolder.tv_description.setText(newsinfo.getDescription());

        viewHolder.tv_type.setText(newsinfo.getType()+"");

        return view;

    }

    class viewHolder{//添加类，封装需要查找的控件        TextView tv_title;

        TextView tv_description;

        TextView  tv_type;

        SmartImageView siv;

 

    }

}

 

3.新建一个名为entity的包名，新建一个NewsInfo的类，内容如下：

 

package cn.edu.bzu.anew.entity;public class NewsInfo
{

    private  String icon;

    private  String title;

    private  String description;

    private  int type;

    private  long comment;

 

    public NewsInfo(String icon, String title, String description, int type, long comment)
{

        this.icon =
icon;

        this.title =
title;

        this.description =
description;

        this.type =
type;

        this.comment =
comment;

    }

 

    public String getIcon() {

        return icon;

    }

 

    public void setIcon(String icon) {

        this.icon =
icon;

    }

 

    public String getTitle() {

        return title;

    }

 

    public void setTitle(String title) {

        this.title =
title;

    }

 

    public String getDescription() {

        return description;

    }

 

    public void setDescription(String description) {

        this.description =
description;

    }

 

    public int getType() {

        return type;

    }

 

    public void setType(int type)
{

        this.type =
type;

    }

 

    public long getComment() {

        return comment;

    }

 

    public void setComment(long comment)
{

        this.comment =
comment;

    }

}

 

4.新建一个名为Tools的包，包下新建一个名为JsonParse的类，内容如下：

package cn.edu.bzu.anew.Tools;import com.google.gson.Gson;import com.google.gson.reflect.TypeToken;importjava.lang.reflect.Type;import java.util.List;import cn.edu.bzu.anew.entity.NewsInfo;

/** * Created by Administrator on 2017/5/18. */public class JsonParse {

    public  static List<NewsInfo>getNewsInfo(String json){

        Gson gson =new Gson();

        Type listType=new TypeToken<List<NewsInfo>> (){

        }.getType();

        List<NewsInfo>newsInfos=gson.fromJson(json,listType);

        return  newsInfos;

    }

}

 

5.MainActivity的内容如下：

package cn.edu.bzu.anew;

import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;importandroid.widget.LinearLayout;import android.widget.ListView;import android.widget.Toast;importcom.loopj.android.http.AsyncHttpClient;import com.loopj.android.http.AsyncHttpResponseHandler;importjava.io.UnsupportedEncodingException;import java.util.List;import cn.edu.bzu.anew.Tools.JsonParse;importcn.edu.bzu.anew.adapter.NewsAdapter;import cn.edu.bzu.anew.entity.NewsInfo;

 

public class MainActivity extends AppCompatActivity
{

    private ListView lvNews;

    private List<NewsInfo>  newsInfos;

    private LinearLayout loading;

 

    @Override    protected void onCreate(Bundle
savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        lvNews=(ListView)findViewById(R.id.lv_news);

        loading=(LinearLayout)findViewById(R.id.loading);

        fillData();

 

    }

    private  void  fillData(){

        AsyncHttpClient client =new  AsyncHttpClient();

 

        client.get("http://10.51.5.16:8080/NewsInfo.json",new AsyncHttpResponseHandler(){

            @Override            public void onSuccess(int i,
org.apache.http.Header[] headers, byte[] bytes) {

                try{

                    String json=new String(bytes,"utf-8");

                    newsInfos= JsonParse.getNewsInfo(json);

                    if(newsInfos==null){

                        Toast.makeText(MainActivity.this,"解析失败",
Toast.LENGTH_LONG).show();

                    }else{

                        loading .setVisibility(View.INVISIBLE);

                        lvNews.setAdapter(new NewsAdapter(MainActivity.this,newsInfos));

                    }

                } catch (UnsupportedEncodingException e) {

                    e.printStackTrace();

                }

            }

 

            @Override            public void onFailure(int i,
org.apache.http.Header[] headers, byte[] bytes, Throwable throwable) {

 

            }

        } );

    }

}