viewpager的instantiateItem方法position怎么不从零开始

[knxw0001]

activityA中用到了viewpager，viewpager是动态操作view，跳到activityB后，再跳回来A，viewpager的instantiateItem方法的position就不从零开始了，导致数组越界。

代码如下：

public class AdvertAdapter extends PagerAdapter {

	private LinkedList<Advert> adverts;
	private Context mContext;
	private ArrayList<View> imagePageViews;

	public HomeAdvertAdapter(Context mContext, LinkedList<Advert> adverts) {
		this.adverts = adverts;
		this.mContext = mContext;

		imagePageViews = new ArrayList<View>();
	}

	@Override
	public int getCount() {
		return adverts.size();
	}

	@Override
	public boolean isViewFromObject(View arg0, Object arg1) {
		return arg0 == arg1;
	}

	@Override
	public int getItemPosition(Object object) {
		return super.getItemPosition(object);
	}

	@Override
	public void destroyItem(View arg0, int arg1, Object arg2) {
		((ViewPager) arg0).removeView(imagePageViews.get(arg1));
	}

	@Override
	public Object instantiateItem(View arg0, final int position) {
		ImageView imageView = new ImageView(mContext);
		imageView.setScaleType(ScaleType.FIT_XY);
		
		imagePageViews.add((imageView));
		
		((ViewPager) arg0).addView(imagePageViews.get(position));

		return imagePageViews.get(position);
	}
}