Android ViewPager怎么去实现无限循环滚动回绕效果

package zhangphil.demo;import java.util.Random;import android.app.Activity;import android.graphics.Color;import android.os.Bundle;import android.support.v4.view.PagerAdapter;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); LoopViewPager viewpager = (LoopViewPager) findViewById(R.id.viewpager); viewpager.setAdapter(new SamplePagerAdapter()); } public class SamplePagerAdapter extends PagerAdapter { private final Random random = new Random(); private int mSize; public SamplePagerAdapter() { mSize = 5; } public SamplePagerAdapter(int count) { mSize = count; } @Override public int getCount() { return mSize; } @Override public boolean isViewFromObject(View view, Object object) { return view == object; } @Override public void destroyItem(ViewGroup view, int position, Object object) { view.removeView((View) object); } @Override public Object instantiateItem(ViewGroup view, int position) { TextView textView = new TextView(view.getContext()); textView.setText(position + 1 + ""); textView.setBackgroundColor(0xff000000 | random.nextInt(0x00ffffff)); textView.setGravity(Gravity.CENTER); textView.setTextColor(Color.WHITE); textView.setTextSize(50); view.addView(textView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT); return textView; } // 增加item public void addItem() { mSize++; notifyDataSetChanged(); } // 删除item public void removeItem() { mSize--; mSize = mSize < 0 &#63; 0 : mSize; notifyDataSetChanged(); } }}