Viewpager的轮播

public class MainActivity extends AppCompatActivity {

private ViewPager pager;
private String url="http://www.93.gov.cn/93app/data.do?channelId=0&startNum=0";
private Handler handler=new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);

int item = pager.getCurrentItem();
item++;
pager.setCurrentItem(item);

sendEmptyMessageDelayed(0,500);
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

pager = findViewById(R.id.pager);

if(TextUtil.iscon(MainActivity.this))
{
MyTask task = new MyTask(new MyTask.Back() {
@Override
public void setDate(String s) {
Gson gson = new Gson();
Bean json = gson.fromJson(s, Bean.class);
List<String> lean=new ArrayList<>();
List<Bean.DataBean> data = json.getData();
List<Bean.DataScrollBean> list = json.getDataScroll();

for (int i=0;i<data.size();i++)
{
lean.add(data.get(i).getIMAGEURL());
}

handler.sendEmptyMessageDelayed(0,500);

MyAdapter adapter=new MyAdapter(MainActivity.this, lean);
pager.setAdapter(adapter);
}
});
task.execute(url);
}else {
TextUtil.open(MainActivity.this);
}
}
}

public class MyAdapter extends PagerAdapter{private Context context;private List<String> lean;public MyAdapter(Context context, List<String> lean) {this.context = context;this.lean = lean;}@Overridepublic int getCount() {return Integer.MAX_VALUE;}@Overridepublic boolean isViewFromObject(View view, Object object) {return view==object;}@Overridepublic Object instantiateItem(ViewGroup container, int position) {ImageView imageView = new ImageView(context);ImageLoader.getInstance().displayImage(lean.get(position%lean.size()),imageView);container.addView(imageView);return imageView;}@Overridepublic void destroyItem(ViewGroup container, int position, Object object) {container.removeView((View) object);}}