XListView实现网络加载图片和下拉刷新

 本文实例为大家分享了xlistview实现网络加载图片，和下拉刷新的功能，供大家参考，具体内容如下

mainactivity.java

public class mainactivity extends appcompatactivity {

 private xlistview contents;

 private int page = 0;
 private mybaseadapter adapter;

 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);

  contents = findviewbyid(r.id.contents);
  adapter = new mybaseadapter(getlayoutinflater());
  contents.setadapter(adapter);

  //是否开启下拉刷新 上拉加载
  //contents.setpullrefreshenable(false);
  contents.setpullloadenable(true);

  contents.setxlistviewlistener(new xlistview.ixlistviewlistener() {
   @override public void onrefresh() {
    page = 0;
    loaddata(page);
    //加载刷新数据
   }

   @override public void onloadmore() {
    loaddata(page);
   }
  });

  //一进来就去加载第一页数据
  loaddata(page);
 }

 private string url =
   "http://apis.juhe.cn/cook/query?key=3ec004200a6a2f4cf4774e480c006375&menu=%e8%a5%bf%e7%ba%a2%e6%9f%bf&rn=10&pn=";

 private void loaddata(int page) {
  string requesturlwithpagenum = url + page;

  //加载网络数据
  new asynctask<string, void, list<dataitem>>() {

   @override protected list<dataitem> doinbackground(string... strings) {
    responsebean responsebean = null;
    try {
     url url = new url(strings[0]);
     httpurlconnection urlconnection = (httpurlconnection) url.openconnection();
     urlconnection.setrequestmethod("get");
     urlconnection.setconnecttimeout(5000);
     urlconnection.setreadtimeout(5000);

     int responsecode = urlconnection.getresponsecode();
     if (responsecode == 200) {
      string str = stream2string(urlconnection.getinputstream());
      responsebean = new gson().fromjson(str, responsebean.class);
     } else {
      //
     }
     return responsebean == null ? null : responsebean.getresult().getdata();
    } catch (malformedurlexception e) {
     e.printstacktrace();
    } catch (ioexception e) {
     e.printstacktrace();
    }

    return null;
   }

   @override protected void onpostexecute(list<dataitem> dataitems) {
    if (dataitems == null) {
     toast.maketext(mainactivity.this, "请求数据错误", toast.length_long).show();
     return;
    }

    //更新数据
    updatedata(dataitems);
    loadcompleted();
   }
  }.execute(url);
 }

 private string stream2string(inputstream is) throws ioexception {
  bufferedreader br = new bufferedreader(new inputstreamreader(is));
  stringbuilder sb = new stringbuilder();
  for (string tmp = br.readline(); tmp != null; tmp = br.readline()) {
   sb.append(tmp);
  }

  return sb.tostring();
 }

 private void updatedata(list<dataitem> datas) {
  if (page == 0) {
   adapter.setdatas(datas);
  } else {
   adapter.adddatas(datas);
  }
 }

 //通过 加载 / 刷新 完成
 private void loadcompleted() {
  //通过listview：刷新、加载完成
  page++;
  contents.stoploadmore();
  contents.stoprefresh();
 }
}

mybaseadapter.java

public class mybaseadapter extends baseadapter {

 private list<dataitem> mdatas;
 protected layoutinflater minflater;

 /**
  * 更新数据
  */
 public void setdatas(list<dataitem> datas) {
  mdatas.clear();
  if (datas != null) {
   mdatas.addall(datas);
  }
  notifydatasetchanged();
 }

 /**
  * 追加数据
  */
 public void adddatas(list<dataitem> datas) {
  if (datas != null) {
   mdatas.addall(datas);
   notifydatasetchanged();
  }
 }

 public mybaseadapter(layoutinflater minflater) {
  this.minflater = minflater;
  mdatas = new arraylist<>();
 }

 @override public int getcount() {
  return mdatas.size();
 }

 @override public dataitem getitem(int position) {
  return mdatas.get(position);
 }

 @override public long getitemid(int position) {
  return position;
 }

 @override public view getview(int position, view convertview, viewgroup parent) {
  baseviewholder viewholder = null;

  if (convertview == null) {
   convertview = minflater.inflate(r.layout.item, parent, false);
   viewholder = new baseviewholder(convertview);
  } else {
   viewholder = (baseviewholder) convertview.gettag();
  }

  viewholder.binddata(getitem(position));

  return convertview;
 }

 public class baseviewholder {
  private view itemview;

  private imageview icon;
  private textview title;
  private textview date;

  public baseviewholder(view itemview) {
   this.itemview = itemview;
   title = itemview.findviewbyid(r.id.title);
   date = itemview.findviewbyid(r.id.date);
   icon = itemview.findviewbyid(r.id.icon);

   itemview.settag(this);
  }

  public void binddata(dataitem dataitem) {
   title.settext(dataitem.gettitle());
   date.settext(dataitem.getid());
   imageloader.getinstance().displayimage(dataitem.getfirstimageurl(), icon,
     imageloaderconfigs.getdefaultdisplayimageoptions(icon.getcontext()));
  }
 }
}
imageloader.java
  public class imageloaderconfigs {
 public static imageloaderconfiguration getimageloaderconfiguration(context context) {
  imageloaderconfiguration configuration = new imageloaderconfiguration.builder(context)
    //内在缓存额外选项， 最大的宽度，高度
    //.memorycacheextraoptions(480, 800) // default = device screen dimensions 内存缓存文件的最大长宽
    //.diskcacheextraoptions(480, 800, null) // 本地缓存的详细信息(缓存的最大长宽)，最好不要设置这个
    //线程池配置
    //.taskexecutor()
    //.taskexecutorforcachedimages()
    //.threadpoolsize(3) // default 线程池内加载的数量
    //.threadpriority(thread.norm_priority - 2) // default 设置当前线程的优先级
    //任务处理优先级 fist in fist out
    //.tasksprocessingorder(queueprocessingtype.fifo) // default
    //内存中不缓存一张图片的多个尺寸大小
    //.denycacheimagemultiplesizesinmemory()
    //内在缓存策略
    //.memorycache(new lrumemorycache(2 * 1024 * 1024)) //可以通过自己的内存缓存实现
    //内存缓存大小
    //.memorycachesize(2 * 1024 * 1024) // 内存缓存的最大值
    //内在缓存大小：占用百分比
    .memorycachesizepercentage(13) // default
    //磁盘缓存策略
    //.diskcache(new lrudiskcache()) // default 可以自定义缓存路径
    //磁盘缓存大小
    .diskcachesize(50 * 1024 * 1024) // 50 mb sd卡(本地)缓存的最大值
    //.diskcachefilecount(100) // 可以缓存的文件数量
    // default为使用hashcode对uil进行加密命名， 还可以用md5(new md5filenamegenerator())加密
    //.diskcachefilenamegenerator(new hashcodefilenamegenerator())
    //.imagedownloader(new baseimagedownloader(context)) // default
    //(new baseimagedecoder(false)) // default
    //加载具体图片时的一些配置
    .defaultdisplayimageoptions(displayimageoptions.createsimple()) // default
    .writedebuglogs() // 打印debug log
    .build();

  return configuration;
 }

 public static displayimageoptions getdefaultdisplayimageoptions(context context) {
  displayimageoptions displayimageoptions = new displayimageoptions.builder()
    //是否缓存
    .cacheinmemory(true)
    .cacheondisk(true)
    //rgb 565  r红色占5  g绿色占6  b蓝色占5 -> 2字节
    //alpha
    //argb 4444  4 4 4 4 -> 2字节
    //argb 8888  -> 4字节

    //10 * 10 用rgb565 -> 10*10*2

    .bitmapconfig(bitmap.config.rgb_565)
    //加载时、加载错误时展示什么内容
    .showimageonloading(r.mipmap.ic_launcher)
    .showimageonfail(r.mipmap.ic_launcher)
    //
    .imagescaletype(imagescaletype.exactly_stretched)

    //加载效果
    //ctrl + p
    .displayer(new circlebitmapdisplayer())
    .build();

  //ctrl + h
  //bitmapdisplayer;
  return displayimageoptions;
 }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。