ViewPager的用法和实现过程

看图先：

页面中填充内容是随机关键词飞入和飞出动画效果，随后会更新，如今请先无视吧

首先是 导入jar包   下载地址：android-support-v4.jar

布局文件中加入viewPager布局

        <android.support.v4.view.ViewPager
            android:id="@+id/search_viewpager"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center" >
        </android.support.v4.view.ViewPager>

再创建两个item布局用于填充在ViewPager里

然后就是Activity了，主要写了左右滑动切换页面，另一个小图片随页面切换 位移的动画效果

public class SearchAllcityActivity extends Activity {

	private KeywordsFlow keywordsFlow;
	private ViewPager viewPager;
	private ImageView imageView;
	private List<View> lists = new ArrayList<View>();
	private ViewPagerAdapter adapter;
	private Bitmap cursor;
	private int offSet;
	private int currentItem;
	private Matrix matrix = new Matrix();
	private int bmWidth;
	private Animation animation;
	private Button shuaxin_sq, shuaxin_fl;

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.search_allcity);

		// 随页面滑动图片
		imageView = (ImageView) findViewById(R.id.viewpaget_img);
		// 热门商圈和热门分类 页面加入到viewPager集合
		lists.add(getLayoutInflater().inflate(R.layout.search_hot_shangqu, null));
		lists.add(getLayoutInflater().inflate(R.layout.search_hot_fenlei, null));
		// 初始化滑动图片位置
		initeCursor();
		adapter = new ViewPagerAdapter(lists);
		viewPager = (ViewPager) findViewById(R.id.search_viewpager);
		viewPager.setAdapter(adapter);
		// ViewPager滑动监听器
		viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

			@Override
			public void onPageSelected(int arg0) {
				// TODO Auto-generated method stub
				// 当滑动时，顶部的imageView是通过animation缓慢的滑动
				switch (arg0) {
				case 0:
					if (currentItem == 1) {
						animation = new TranslateAnimation(offSet * 2 + bmWidth, 0, 0,0);
					} else if (currentItem == 2) {
						animation = new TranslateAnimation(offSet * 4 + 2 * bmWidth, 0,0, 0);
					}

					break;
				case 1:
					if (currentItem == 0) {
						animation = new TranslateAnimation(0, offSet * 2 + bmWidth, 0,0);
					} else if (currentItem == 2) {
						animation = new TranslateAnimation(4 * offSet + 2 * bmWidth,offSet * 2 + bmWidth, 0, 0);
					}

					break;
				}
				currentItem = arg0;
				animation.setDuration(500);
				animation.setFillAfter(true);
				imageView.startAnimation(animation);

			}

			@Override
			public void onPageScrolled(int arg0, float arg1, int arg2) {
				// TODO Auto-generated method stub

			}

			@Override
			public void onPageScrollStateChanged(int arg0) {
				// TODO Auto-generated method stub

			}
		});

	}

	/**
	 * 计算滑动的图片的位置
	 */
	private void initeCursor() {
		cursor = BitmapFactory.decodeResource(getResources(),R.drawable.viewpager_img);
		bmWidth = cursor.getWidth();
		DisplayMetrics dm;
		dm = getResources().getDisplayMetrics();
		offSet = (dm.widthPixels - 2 * bmWidth) / 4;
		matrix.setTranslate(offSet, 0);
		imageView.setImageMatrix(matrix); // 须要iamgeView的scaleType为matrix
		currentItem = 0;
	}

}

最后，不能忘了ViewPager的Adapter

public class ViewPagerAdapter extends PagerAdapter{

    List<View> viewLists;

    public ViewPagerAdapter(List<View> lists)
    {
        viewLists = lists;
    }

    @Override
    public int getCount() {                                                                 //获得size
        // TODO Auto-generated method stub
        return viewLists.size();
    }

    @Override
    public boolean isViewFromObject(View arg0, Object arg1) {
        // TODO Auto-generated method stub
        return arg0 == arg1;
    }

    @Override
    public void destroyItem(View view, int position, Object object)                       //销毁Item
    {
        ((ViewPager) view).removeView(viewLists.get(position));
    }

    @Override
    public Object instantiateItem(View view, int position)                                //实例化Item
    {
        ((ViewPager) view).addView(viewLists.get(position), 0);

        return viewLists.get(position);
    }

}