Andriod使用多线程实现轮播图片

<?xml version="1.0" encoding="utf-8"?>
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical"
 tools:context="com.example.administrator.chinesezodiacapplication.mainactivity">
 <imageview
  android:id="@+id/imgnet"
  android:layout_width="match_parent"
  android:layout_height="0dp"
  android:layout_weight="1"
  android:src="@drawable/zi"
  />
 <linearlayout
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="horizontal">
  <button
   android:id="@+id/btnstart"
   android:layout_width="0dp"
   android:layout_weight="1"
   android:layout_height="wrap_content"
   android:text="开始播放"
   android:textsize="16dp"
   />
  <button
   android:id="@+id/btnpause"
   android:layout_width="0dp"
   android:layout_weight="1"
   android:layout_height="wrap_content"
   android:text="暂停播放"
   android:textsize="16dp"
   />
 </linearlayout>
</linearlayout>

public class mainactivity extends appcompatactivity {
 private button btnstart;
 private button btnpause;
 private imageview imageview;
 private thread thread;
 private handler handler;
 private int msg_img_change = 1001;
 private boolean ispause = true;
 private string url1 ="https://qqpublic.qpic.cn/qq_public/0/0-2366261503-87ffa35d0792fec1048083429d12687e/900";
 private string url2 ="https://qqpublic.qpic.cn/qq_public/0/0-3097962509-f7cfddbde07dafac9568fe9abfe7153f/900";
 private string url3 ="https://qqpublic.qpic.cn/qq_public/0/0-2851260680-186f3c52c3ddcb6bbaee05aef83d89da/900?tp=webp";
 private string url4 ="https://qqpublic.qpic.cn/qq_public/0/0-2738303735-b0fd9aba222886fcfa325d1ad4db6156/900?tp=webp";
 private string url5 ="https://qqpublic.qpic.cn/qq_public/0/0-2776144047-cd42fe909edd232753d51c54329d7ba6/900?tp=webp";
 private string url6 ="https://qqpublic.qpic.cn/qq_public/0/0-2628537209-cfba5c4c446cc492775303478f5825a2/900?tp=webp";
 private string url7 ="https://qqpublic.qpic.cn/qq_public/0/0-3079871717-6b0b52bde99eb32e481f049c077a3e6d/900?tp=webp";
 private string url8 ="https://qqpublic.qpic.cn/qq_public/0/0-2906573180-bb6e88099d4db7c27354591d8620a6bb/900?tp=webp";
 private string url9 ="https://qqpublic.qpic.cn/qq_public/0/0-2365621724-14715472acea17237f988207a7ea862f/900?tp=webp";
 private string url10 ="https://qqpublic.qpic.cn/qq_public/0/0-2362096419-a1371db9f39e23b07061e1e4d5e4b995/900?tp=webp";
 private string url11 ="https://qqpublic.qpic.cn/qq_public/0/0-2473426908-4c9010d824ef29e08bf20c6e32d3502a/900?tp=webp";
 private string url12="https://qqpublic.qpic.cn/qq_public/0/0-3067218096-f5a001f06e9d0c9b91e15db4dff5fb7b/900?tp=webp";
 private string[] imgurls ={url1,url2,url3,url4,url5,url6,url7,url8,url9,url10,url11,url12};
 private int index = 0;
 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);
  initviews();
  initthread();
  inithandler();
 }
 private void inithandler() {
  handler = new handler(new handler.callback() {
   @override
   public boolean handlemessage(message message) {
    if(message.what ==msg_img_change){
     glide.with(mainactivity.this).load(imgurls[message.arg1]).into(imageview);
     return true;
    }
    return false;
   }
  });
 }
 private void initthread() {
  new thread(new runnable(){
   @override
   public void run() {
    while (true){
     if(!ispause){
      index =(index+1)%imgurls.length;
      message msg = message.obtain();
      msg.what = msg_img_change;
      msg.arg1 =index;
      handler.sendmessage(msg);
     }
     try {
      thread.sleep(2000);
     } catch (interruptedexception e) {
      e.printstacktrace();
     }
    }
   }
  }).start();
 }
 private void initviews() {
  initimageview();
  initbutton();
 }
 private void initbutton() {
  btnstart = (button) findviewbyid(r.id.btnstart);
  btnstart.setonclicklistener(new view.onclicklistener() {
   @override
   public void onclick(view view) {
    ispause = false;
   }
  });
  btnpause = (button) findviewbyid(r.id.btnpause);
  btnpause.setonclicklistener(new view.onclicklistener() {
   @override
   public void onclick(view view) {
    ispause = true;
   }
  });
 }
 private void initimageview() {
  imageview = (imageview) findviewbyid(r.id.imgnet);
 }
}