一、实验目的
1.掌握开源项目AsyncHttpClient的使用
2.掌握如何进行JSON解析
二、实验仪器
Andriod Studio
三、实验任务
使用开源项目AsyncHttpClient和SmartImageView完成新闻客户端案例,该案例实现获取服务器的XML文件并将其解析出来捆绑显示到ListView上。
1.运行效果图
2.实现代码
(1)activity_main,xml,程序对应的布局文件,用一个相对布局嵌套一个帧布局,帧布局里面嵌套一个线性布局来实现,用到一个ProgressBar一个TextView和一个ListView控件。
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="cn.edu.bzu.anew.MainActivity">
android:layout_height="match_parent">
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical"
android:visibility="invisible">
android:layout_height="wrap_content" />
android:layout_height="wrap_content"
android:text="正在加载信息..." />
android:layout_width="match_parent"
android:layout_height="match_parent" />
(2)news_item.xml,ListView的Item布局文件,
用到了开源项目SmartImageView,需要添加炸包,下载地址:(https://github.com/loopj/andoid-smart-image-view)。
android:layout_height="65dp">
android:layout_width="80dp"
android:layout_height="60dp"
android:scaleType="centerCrop"
android:src="@mipmap/ic_launcher"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true">
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" />
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" />
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" />
(3)MainActivity,界面交互代码,用到了开源项目AsyncHttpClient,需要下载源代码,下载地址:(https://github.com/loopj/andoid-async-http)。
public class MainActivity extends AppCompatActivity {
private ListView lvNews;
private List
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://10.51.26.107:8080/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) {
}
} );
}
}
(4)NewsAdapter适配器
public class NewsAdapter extends ArrayAdapter
public NewsAdapter(Context context, List
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;
}
}
(5)NewsInfo实体类,封装属性
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;
}
}
(6)newsInfo.json,解析出的json包中的内容(使用谷歌的开源库GSON解析)
{
"icon": "http://192.168.1.109:8080/images/a.jpg",
"title": "科技温暖世界",
"content": "进入一个更有爱的领域",
"type": "1",
"comment": "69"
},
{
"icon": "http://192.168.1.109:8080/images/b.jpg",
"title": "《神武》",
"content": "新美术资源盘点,视觉新体验",
"type": "2",
"comment": "35"
},
{
"icon": "http://192.168.1.109:8080/images/c.jpg",
"title": "南北车正式公布合并",
"content": "南北车将于今日正式公布合并",
"type": "3",
"comment": "2"
},
{
"icon": "http://192.168.1.109:8080/images/d.jpg",
"title": "萌呆了!汪星人抱玩偶酣睡",
"content": "汪星人抱玩偶酣睡,萌翻网友",
"type": "1",
"comment": "25"
},
{
"icon": "http://192.168.1.109:8080/images/e.jpg",
"title": "风力发电进校园",
"content": "风力发电普进校园",
"type": "2",
"comment": "26"
},
{
"icon": "http://192.168.1.109:8080/images/f.jpg",
"title": "地球一小时",
"content": "地球熄灯一小时",
"type": "1",
"comment": "23"
},
{
"icon": "http://192.168.1.109:8080/images/g.jpg",
"title": "最美公路",
"content": "最美公路,难以想象",
"type": "1",
"comment": "23"
}
(7)JsonParse工具类,解析JSON数据
public class JsonParse {
public static List
//使用GSON库解析json数据
Gson gson =new Gson();
Type listType=new TypeToken> (){
}.getType();
List
return newsInfos;
}
}
(8)配置Tomcat服务器
Tomcat下载地址:(http://tomcat.apache.org/ )
在根目录下找到bin文件,运行该文件夹下的startup.bat文件启动tomcat服务器。
在webapps/Root文件夹下,放置JSON文件并创建一个img文件夹放置相应的图片。
(9)添加权限
本案例需要访问网络,因此需要在AndroidMainfest.xml里面配置相应的权限