1.AsyncHttpClient的使用
在Android开发中，发送、处理HTTP请求十分常见，如果每次与服务器进行数据交互都需要去开启一个子线程，这样是非常麻烦的。为了解决这个问题，一些开发者开发出了开源项目——AsyncHttpClient。
https://github.com/loopj/android-async-http
http://hc.apache.org/download.cgi
AsyncHttpClient是对HttpClient的再次包装。AsyncHttpClient的特点有，发送异步HTTP请求、HTTP请求发生在UI线程之外、内部采用了线程池来处理并发请求，而且它使用起来比HttpClient更加简便。•
2. SmartImageView的使用
市面上一些常见软件，例如手机QQ、天猫、京东商场等，都加载了大量网络上的图片。用Android自带的API实现这一功能十分麻烦而且耗时。为此，编程爱好者开发了一个开源项目——SmartImageView。
https://github.com/loopj/android-smart-image-view
开源项目SmartImageView的出现主要是为了加速从网络上加载图片，它继承自ImageView类，支持根据URL地址加载图片、支持异步加载图片、支持图片缓存等。
1.创建主界面：
<span style="font-size:18px;"><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></span>2.创建ListView中的Item布局
<span style="font-size:18px;"><?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> </span>3.创建newsInfo类
<span style="font-size:18px;">public class NewsInfo { private String iconPath; private String title; private String description; private int type; private long comment; public NewsInfo(String iconPath, String title, String description, int type, long comment) { this.iconPath = iconPath; this.title = title; this.description = description; this.type = type; this.comment = comment; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } 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 getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getIconPath() { return iconPath; } public void setIconPath(String iconPath) { this.iconPath = iconPath; } }</span>4.创建ListView适配器NewsAdapter
<span style="font-size:18px;">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.tv_title.setText(newsinfo.getTitle());//传递题目 viewHolder.tv_description.setText(newsinfo.getDescription());//传递的为字符串 viewHolder.tv_type.setText(newsinfo.getType()+"");//传递的为int类型，所以加上空格转换为了字符串类型 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; } }</span>5.最后编写主函数MainActivity，代码如下：
<span style="font-size:18px;">public class MainActivity extends AppCompatActivity { private ListView lv_news; private LinearLayout loading; private List<NewsInfo> newsInfos; @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 client=new AsyncHttpClient(); client.get("http://10.51.17.215:8080/NewsInfo.json",new AsyncHttpResponseHandler(){ @Override public void onSuccess(int i, cz.msebera.android.httpclient.Header[] headers, byte[] bytes) { //请求成功 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_SHORT).show(); }else{ loading.setVisibility(View.INVISIBLE); lv_news.setAdapter(new NewsAdapter(MainActivity.this,newsInfos)); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } @Override public void onFailure(int i, cz.msebera.android.httpclient.Header[] headers, byte[] bytes, Throwable throwable) { } }); } }</span>多运用框架可以节省开发时间与成本，应多运用开源框架去做Android项目。
