Android中viewPager兑现欢迎引导

public class MainActivity extends Activity implements OnClickListener, OnPageChangeListener{	 private ViewPager vp;	    private ViewPagerAdapter vpAdapter;	    private List<View> views;	    private int lastValue = -1;	    private Bitmap bitmap;	    	    //引导图片资源	    private static final int[] pics = { R.drawable.guide1,	            R.drawable.guide2, R.drawable.guide3,	            R.drawable.guide4,R.drawable.guide5 };	    	    //底部小店图片	    private ImageView[] dots ;	    	    //记录当前选中位置	    private int currentIndex;	    	    /** Called when the activity is first created. */	    @Override	    public void onCreate(Bundle savedInstanceState) {	        super.onCreate(savedInstanceState);	        setContentView(R.layout.main);	        	        views = new ArrayList<View>();	       	        LinearLayout.LayoutParams mParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,	                LinearLayout.LayoutParams.WRAP_CONTENT);	        	        //初始化引导图片列表	        for(int i=0; i<pics.length; i++) {	            ImageView iv = new ImageView(this);	            iv.setLayoutParams(mParams);	            iv.setImageBitmap(getBitmap(pics[i]));	            views.add(iv);	        }	        vp = (ViewPager) findViewById(R.id.viewpager);	        //初始化Adapter	        vpAdapter = new ViewPagerAdapter(views);	        vp.setAdapter(vpAdapter);	        //绑定回调	        vp.setOnPageChangeListener(this);	        	        //初始化底部小点	        initDots();	        	    }	    /**	     * 以最小内存获取资源图片	     * @param resId	     * @return	     */	    private Bitmap getBitmap(int resId){	    	BitmapFactory.Options opt = new BitmapFactory.Options();	    	opt.inPreferredConfig = Bitmap.Config.RGB_565;	    	opt.inPurgeable = true;	    	opt.inInputShareable = true;	    	InputStream is = this.getResources().openRawResource(resId);	    	bitmap = BitmapFactory.decodeStream(is, null, opt);	    	return bitmap;	    }	    private void initDots() {	        LinearLayout ll = (LinearLayout) findViewById(R.id.ll);	        dots = new ImageView[pics.length];	        //循环取得小点图片	        for (int i = 0; i < pics.length; i++) {	            dots[i] = (ImageView) ll.getChildAt(i);	            dots[i].setEnabled(true);//都设为灰色	            dots[i].setOnClickListener(this);	            dots[i].setTag(i);//设置位置tag，方便取出与当前位置对应	        }	        currentIndex = 0;	        dots[currentIndex].setEnabled(false);//设置为白色，即选中状态	    }	    	    /**	     *设置当前的引导页 	     */	    private void setCurView(int position)	    {	        if (position < 0 || position >= pics.length) {	            return;	        }	        vp.setCurrentItem(position);	    }	    /**	     *这只当前引导小点的选中 	     */	    private void setCurDot(int positon)	    {	        if (positon < 0 || positon > pics.length - 1 || currentIndex == positon) {	            return;	        }	        dots[positon].setEnabled(false);	        dots[currentIndex].setEnabled(true);	        currentIndex = positon;	    }	    //当滑动状态改变时调用	    @Override	    public void onPageScrollStateChanged(int arg0) {          if(arg0 == 0){        	   if(lastValue == pics.length-1){        		   Toast.makeText(this, "已经是最后一张了", Toast.LENGTH_SHORT).show();        	   }           }	        	    }	    //当当前页面被滑动时调用	    @Override	    public void onPageScrolled(int arg0, float arg1, int arg2) {	    	lastValue = arg0;	    }	    //当新的页面被选中时调用	    @Override	    public void onPageSelected(int arg0) {	        //设置底部小点选中状态	        setCurDot(arg0);	    }	    @Override	    public void onClick(View v) {	        int position = (Integer)v.getTag();	        setCurView(position);	        setCurDot(position);	    }}public class ViewPagerAdapter extends PagerAdapter {	 //界面列表    private List<View> views;        public ViewPagerAdapter (List<View> views){        this.views = views;    }    //销毁arg1位置的界面    @Override    public void destroyItem(View arg0, int arg1, Object arg2) {        ((ViewPager) arg0).removeView(views.get(arg1));            }    @Override    public void finishUpdate(View arg0) {        // TODO Auto-generated method stub            }    //获得当前界面数    @Override    public int getCount() {        if (views != null)        {            return views.size();        }                return 0;    }        //初始化arg1位置的界面    @Override    public Object instantiateItem(View arg0, int arg1) {                ((ViewPager) arg0).addView(views.get(arg1), 0);                return views.get(arg1);    }    //判断是否由对象生成界面    @Override    public boolean isViewFromObject(View arg0, Object arg1) {        return (arg0 == arg1);    }    @Override    public void restoreState(Parcelable arg0, ClassLoader arg1) {        // TODO Auto-generated method stub            }    @Override    public Parcelable saveState() {        // TODO Auto-generated method stub        return null;    }    @Override    public void startUpdate(View arg0) {        // TODO Auto-generated method stub            }}