通过手势实现页面切换，关于Viewpaper介绍。

在android 1.6+的版本中增加了Viewpaper类，通过这个类我们可以很简单的实现左右滑动手指切换页面，Viewpaper需要设置PaperAdapter，在PaperAdapter中实现添加或删除View的功能，具体代码：

public class AwesomePagerActivity extends Activity {
    
	private ViewPager awesomePager;

	private Context cxt;
	private AwesomePagerAdapter awesomeAdapter;
	
	private LayoutInflater mInflater;
	private List<View> mListViews;
	
	/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        cxt = this;
        
        awesomeAdapter = new AwesomePagerAdapter();
        awesomePager = (ViewPager) findViewById(R.id.awesomepager);
        awesomePager.setAdapter(awesomeAdapter);
        
        mListViews = new ArrayList<View>();
        mInflater = getLayoutInflater();
        mListViews.add(mInflater.inflate(R.layout.layout1, null));
        mListViews.add(mInflater.inflate(R.layout.layout2, null));
        mListViews.add(mInflater.inflate(R.layout.layout3, null));
        
    }
    
    private class AwesomePagerAdapter extends PagerAdapter{

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

	    /**
	     * Create the page for the given position.  The adapter is responsible
	     * for adding the view to the container given here, although it only
	     * must ensure this is done by the time it returns from
	     * {@link #finishUpdate()}.
	     *
	     * @param container The containing View in which the page will be shown.
	     * @param position The page position to be instantiated.
	     * @return Returns an Object representing the new page.  This does not
	     * need to be a View, but can be some other container of the page.
	     */
		@Override
		public Object instantiateItem(View collection, int position) {

			
			((ViewPager) collection).addView(mListViews.get(position),0);
			
			return mListViews.get(position);
		}

	    /**
	     * Remove a page for the given position.  The adapter is responsible
	     * for removing the view from its container, although it only must ensure
	     * this is done by the time it returns from {@link #finishUpdate()}.
	     *
	     * @param container The containing View from which the page will be removed.
	     * @param position The page position to be removed.
	     * @param object The same object that was returned by
	     * {@link #instantiateItem(View, int)}.
	     */
		@Override
		public void destroyItem(View collection, int position, Object view) {
			((ViewPager) collection).removeView(mListViews.get(position));
		}

		
		
		@Override
		public boolean isViewFromObject(View view, Object object) {
			return view==(object);
		}

		
	    /**
	     * Called when the a change in the shown pages has been completed.  At this
	     * point you must ensure that all of the pages have actually been added or
	     * removed from the container as appropriate.
	     * @param container The containing View which is displaying this adapter's
	     * page views.
	     */
		@Override
		public void finishUpdate(View arg0) {}
		

		@Override
		public void restoreState(Parcelable arg0, ClassLoader arg1) {}

		@Override
		public Parcelable saveState() {
			return null;
		}

		@Override
		public void startUpdate(View arg0) {}
    	
    }
    
    
}

 虽然通过修改源码中launcher类也可以实现类似功能，不过比起重写view这种体力活显然这种方法更环保。