使用网络技术————新闻客户端

来源：互联网发布：freebsd和centos 编辑：程序博客网时间：2024/06/05 07:03

在前面学习了开源项目AsyncHttpClient和SmartImageView,下面通过"新闻客户端"案例演示AsyncHttpClient和SmartImageView的综合使用。该案例将要实现获取服务器的XML文件并将其解析出来捆绑显示到ListView上的功能，具体步骤如下：

1.adapter 包下创建NewsAdapter类

NewsAdapter.java
public class NewsAdapter extends ArrayAdapter<NewsInfo>{
public NewsAdapter(Context context, List<NewsInfo> objects){
super(context, R.layout.news_item,objects);
}
public View getView(int position, View convertView, ViewGroup parent){
NewsInfo newsInfo=getItem(position);
ViewHolder viewHolder;
View view=null;
if(convertView==null){
view=View.inflate(getContext(),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);
}
else{
view=convertView;
viewHolder=(viewHolder)view.getTag();
}
}
}

2.创建JSON文件

JsonParse.java
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;
}
}

3.主布局 activity_main.xml文件

activity_main.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" />
</FrameLayout>
</LinearLayout>
4.ListView控件子布局 news_item.xml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>
5. Entity包下创建包下创建实体类实体类NewsInfo

NewsInfo.java
public class NewsInfo {
private String iconPath;
private String title;
private String description;
private int type;
private long comment;

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 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;
}
}

6. 界面逻辑代码的设计与实现
MainActivity.java
public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
private void fillData(){
AsyncHttpClient client=new AsyncHttpClient();
client.get("http://10.3.24.176:8080/NewsInfo.json",new AsyncHttpResponseHandler(){
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(newsInfo==null){
Toast.makeText(MainActivity.this, "解析失败", Toast.LENGTH_SHORT).show();
lvNews.setAdapter(new NewsAdapter(MainActivity.this.newsInfo));
}
}catch(Exception e){
e.printStackTrace();
}

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

}
});
}
}

最终运行效果如下图所示：

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