Android开发模板------ViewPager(一)用PagerAdapter实现图片滑动作为引导页

iewpager可以做很多事情，从最简单的导航，到页面菜单等等。那如何使用它呢，与ListView类似，我们也需要一个适配器，就是PagerAdapter。
首先看布局文件：

<android.support.v4.view.ViewPager  
        android:id="@+id/viewpager"  
        android:layout_width="match_parent"  
        android:layout_height="match_parent" /> 

具体业务逻辑如下：

public class GuideViewActivity extends Activity {  

    private ViewPager vp;  
    private int[] drawables;  
    private ImageView[] imageViews;  

    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_guideview);  
        vp = (ViewPager) findViewById(R.id.viewpager);  

        imageData();  

        vp.setAdapter(new ViewPagerAdapter());  
        vp.setCurrentItem(0);  
    }  

    private void imageData() {  
        drawables = new int[] { R.drawable.guide_help01,  
                R.drawable.guide_help02, R.drawable.guide_help03 };  

        imageViews = new ImageView[drawables.length];  
        for (int i = 0; i < drawables.length; i++) {  
            ImageView img = new ImageView(this);  
            imageViews[i] = img;  
            imageViews[i].setBackgroundResource(drawables[i]);  
        }  
    }  

    public class ViewPagerAdapter extends PagerAdapter {  

        @Override  
        public int getCount() {  
            return drawables.length;  
        }  

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

        @Override  
        public void destroyItem(ViewGroup container, int position, Object object) {  
            ImageView view = imageViews[position];  
            ((ViewPager) container).removeView(view);  
        }  

        @Override  
        public Object instantiateItem(View container, int position) {  
            try {  
                if (imageViews[position].getParent() == null) {  
                    ((ViewPager) container).addView(imageViews[position], 0);  
                } else {  
                    ((ViewGroup) (imageViews[position].getParent()))  
                            .removeView(imageViews[position]);  
                }  
            } catch (Exception e) {  
            }  
            if (position == imageViews.length - 1) {  
                imageViews[position].setOnClickListener(new OnClickListener() {  

                    @Override  
                    public void onClick(View v) {  
                        GuideViewActivity.this.finish();  
                    }  
                });  
            }  
            return imageViews[position % imageViews.length];  
        }  
    }  
}  

除此之外，ViewPager还有更高级的使用方法，比如定时自动滑动，参考http://blog.youkuaiyun.com/dsc114/article/details/46928277 和http://blog.youkuaiyun.com/dsc114/article/details/73614567