案例——新闻客户端

最新推荐文章于 2024-07-21 18:21:18 发布

原创最新推荐文章于 2024-07-21 18:21:18 发布 · 474 阅读

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本文介绍了一个简单的Android新闻应用开发过程，包括布局设计、ListViewItem创建、界面交互代码编写、自定义Adapter实现、XML数据解析及服务器配置等步骤。

1.创建程序（activity_mian.xml）

<?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"
            android:layout_marginTop="5dp"/>
    </FrameLayout>
</LinearLayout>

2.创建ListView Item的布局，ListView的Item布局文件news_item.xml

<?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.编写界面交互代码（MainActivity）

package bzu.edu.cn.imagebrowser;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.Toast;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import java.util.List;
import bzu.edu.cn.imagebrowser.adapter.MyAdapter;
import bzu.edu.cn.imagebrowser.entity.NewsInfo;
import bzu.edu.cn.imagebrowser.tools.JsonParse;

public class Main2Activity extends AppCompatActivity {
    private ListView listView;
    private LinearLayout loading;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        listView=(ListView)findViewById(R.id.lv_news);
        loading=(LinearLayout)findViewById(R.id.loading);
        fillData();
    }
    private void fillData(){

        AsyncHttpClient asyncHttpClient=new AsyncHttpClient();
        asyncHttpClient.get("http://10.3.24.180:8080/NewsInfo.json", new AsyncHttpResponseHandler() {
            @Override
                    public void onSuccess(int i,org.apache.http.Header[] headers, byte[] bytes) {
                        String json;
                        try {
                    json = new String(bytes,"utf-8");

                List<NewsInfo> newsInfos= JsonParse.getNewsInfo(json);
                     if (newsInfos==null){
                         Toast.makeText(Main2Activity.this,"解析失败",Toast.LENGTH_LONG).show();
                     }else{
                         loading.setVisibility(View.INVISIBLE);
                         listView.setAdapter(new MyAdapter(Main2Activity.this,newsInfos));
                     }
                } catch (Exception e) {
                            e.printStackTrace();
                        }
            }

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

            }
        });
    }
}

4.创建Adapter类

package bzu.edu.cn.imagebrowser.adapter;

import android.content.Context;
import android.graphics.Color;
import android.support.annotation.NonNull;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import com.loopj.android.image.SmartImageView;

import org.w3c.dom.Text;

import java.util.List;

import bzu.edu.cn.imagebrowser.R;
import bzu.edu.cn.imagebrowser.entity.NewsInfo;

/**
 * Created by yn on 2017/5/19.
 */

public class MyAdapter extends ArrayAdapter<NewsInfo>{
    public MyAdapter(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);
        View view;
        ViewHolder viewHolder;
        if(convertView==null){
            view= LayoutInflater.from(getContext()).inflate(R.layout.news_item, null);
            viewHolder=new ViewHolder();
            viewHolder.siv_icon=(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);
        }
        else{
            view=convertView;
            viewHolder=(ViewHolder)view.getTag();
        }
        viewHolder.siv_icon.setImageUrl(newsInfo.getIcon());
        viewHolder.tv_title.setText(newsInfo.getTitle());
        viewHolder.tv_description.setText(newsInfo.getContent());
        int type=newsInfo.getType();
        switch (type){
            case 1:
                viewHolder.tv_type.setText("评论:"+newsInfo.getComment());
                break;
            case 2:
                viewHolder.tv_type.setTextColor(Color.RED);
                viewHolder.tv_type.setText("专题");
                break;
            case 3:
                viewHolder.tv_type.setTextColor(Color.BLUE);
                viewHolder.tv_type.setText("LIVE");
                break;
        }
        return view;
    }

    class ViewHolder{
        SmartImageView siv_icon;
        TextView tv_title;
        TextView tv_description;
        TextView tv_type;
    }
}

5.创建工具类解析xml文件

package bzu.edu.cn.imagebrowser.entity;

/**
 * Created by yn on 2017/5/19.
 */

public class NewsInfo {
    private String icon;
    private String title;
    private String content;
    private int type;
    private long comment;

    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;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String description) {
        this.content = content;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getIcon() {
        return icon;
    }

    public void setIcon(String icon) {
        this.icon = icon;
    }
}

6.配置服务器
从服务器上下载一个xml，yincixuyao开启Tomcat服务器。在Tomcat根目录下找到bin文件夹，运行到该文件夹下的startup.bat文件即可开启Tomcat服务器。然后，在tomcat的安装目录打开webapps文件夹，将NewsInfo.xml文件放置在ROOT文件夹下。

7.添加权限（AndriodMainfest.xml）

 <uses-permission android:name="android.permission.INTERNET" />
8.展示效果