PagerAdapter中循环设置ImageView为什么不能设置全局变量

public class MyAdapter extends PagerAdapter {
private List urlList;
private List imageViewList;
private MyAsyncTask asyncTask;
private ImageView imageView;
public MyAdapter(Context context, List urlList) {

    this.urlList = urlList;
    urlList.addAll(urlList);
    imageViewList = new ArrayList<>();
    for (int i = 0; i < urlList.size(); i++) {
              imageView = new ImageView(context);

             asyncTask =new MyAsyncTask(new MyAsyncTask.OnfuckYou() {
                @Override
                public void onFuckSuccessful(Bitmap bitmap) {
                    imageView.setImageBitmap(bitmap);

                }
            });
            asyncTask.execute(urlList.get(i));
        imageViewList.add(imageView);

    }
}

http://blog.csdn.net/xuewater/article/details/44342009