Android使用viewpager实现自动无限轮播图

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
  xmlns:tools="http://schemas.android.com/tools" 
  android:layout_width="match_parent" 
  android:layout_height="match_parent" 
  tools:context="com.maxence.viewpager.MainActivity" > 
  <RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="220dp" > 
    <android.support.v4.view.ViewPager 
      android:id="@+id/vp_pager" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" /> 
      <!-- 作为viewgroup 动态 add 游标 --> 
      <LinearLayout 
        android:id="@+id/ll_container" 
        android:layout_width="match_parent" 
        android:layout_height="30dp" 
        android:gravity="center" 
        android:orientation="horizontal" 
        android:layout_alignParentBottom="true" 
        ></LinearLayout> 
  </RelativeLayout> 
</RelativeLayout> 

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"  
   android:shape="oval"> 
  <stroke 
    android:width="1dip" 
    android:color="#ffffff"/> 
  <solid android:color="#ffffff" /> 
</shape> 

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android"  
  android:shape="oval"> 
  <stroke  
    android:width="1dp" 
    android:color="#ff0000" 
    /> 
  <solid android:color="#ff0000"/> 
</shape> 

 /** 
   * 初始化数据 
   */ 
  private void initData() { 
    mContext = this; 
    int[] i = new int[] { R.drawable.bg_lunbo1, R.drawable.bg_lunbo2, R.drawable.bg_lunbo3, R.drawable.bg_lunbo4 }; 
    al = new ArrayList<ImageView>(); 
    for (int x = 0; x < i.length; x++) { 
      ImageView iv = new ImageView(mContext); 
      iv.setBackgroundResource(i[x]); 
      al.add(iv); 
      View v=new View(mContext); 
      v.setBackgroundResource(R.drawable.point_normal); 
      //有多少张图就放置几个点 
      LayoutParams layoutParams = new LinearLayout.LayoutParams(15, 15);  
            layoutParams.leftMargin = 30;  
      ll_container.addView(v,layoutParams); 
    } 
    vp_pager.setAdapter(new Myadapter()); 
    vp_pager.setOnPageChangeListener(this); 
    vp_pager.setCurrentItem(al.size()*1000); //这个是无线轮询的关键 
    ll_container.getChildAt(0).setBackgroundResource(R.drawable.point_select); 
    prePosition=0; 
  } 

class Myadapter extends PagerAdapter { 
    @Override 
    public int getCount() { 
      return Integer.MAX_VALUE; // 要无限轮播 
    } 
    @Override 
    public boolean isViewFromObject(View arg0, Object arg1) { 
      return arg0 == arg1; 
    } 
    @Override 
    public Object instantiateItem(ViewGroup container, int position) { 
        int position1=position % al.size();    
        ImageView imageView = al.get(position1); 
        container.addView(imageView); 
        return imageView; 
    } 
    @Override 
    public void destroyItem(ViewGroup container, int position, Object object) { 
      container.removeView((View)object); 
    } 
  } 

vp_pager.setOnPageChangeListener(this); 

@Override 
public void onPageScrollStateChanged(int arg0) { 
} 
@Override 
public void onPageScrolled(int arg0, float arg1, int arg2) { 
} 
@Override 
public void onPageSelected(int position) { 
   int newPosition = position % al.size();  
   ll_container.getChildAt(newPosition).setBackgroundResource(R.drawable.point_select); 
   ll_container.getChildAt(prePosition).setBackgroundResource(R.drawable.point_normal); 
   prePosition=newPosition; 
} 

/** 
   * 自动轮询 
   */ 
  private void pollint() { 
   pThread = new PollThread(); 
   pThread.start(); 
  } 
class PollThread extends Thread{ 
    @Override 
    public void run() { 
      while (poll){          
                try { 
          Thread.sleep(2000); 
        } catch (InterruptedException e) { 
          e.printStackTrace(); 
        }