【ViewPager的学习】一、简单使用

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="200dp" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@id/viewpager"
        android:background="#33000000"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/image_desc"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="@string/app_name"
            android:textColor="@android:color/white"
            android:textSize="18sp" />

        <LinearLayout
            android:id="@+id/point_group"
            android:layout_width="wrap_content"
            android:layout_gravity="center_horizontal"
            android:layout_height="wrap_content"
            android:orientation="horizontal" >
        </LinearLayout>
    </LinearLayout>

</RelativeLayout>

public class MainActivity extends Activity {

	private ViewPager viewPager;
	// 图片资源ID
	private final int[] imageIds = { R.drawable.a, R.drawable.b, R.drawable.c,	R.drawable.d, R.drawable.e };
	private ArrayList<ImageView> imageList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        viewPager = (ViewPager) findViewById(R.id.viewpager);
  
        imageList = new ArrayList<ImageView>();
        
        for (int i = 0; i < imageIds.length; i++) {
        	ImageView im = new ImageView(this);
			im.setBackgroundResource(imageIds[i]);
			imageList.add(im);		
		}
//同ListView一样，ViewPager也需要Adapter管理数据
        viewPager.setAdapter(new MyAdapter());
        
    }

/**
*	自定义Adapter，必须实现这4个方法
*/
    private class MyAdapter extends PagerAdapter{

    	/**
    	 * 返回viewPager元素数量
    	 */
		@Override
		public int getCount() {
			return imageList.size();
		}

		/**
		 * 实例化一个元素
		 */
		@Override
		public Object instantiateItem(ViewGroup container, int position) {
			
			container.addView(imageList.get(position));
			//container = imageIds[position];
//			return super.instantiateItem(container, position);
			return imageList.get(position);
		}
    	
		/**
		 * 判断是否相等
		 */
		@Override
		public boolean isViewFromObject(View arg0, Object arg1) {
			// TODO 自动生成的方法存根
			return arg0 == (View)arg1;
		}

		/**
		 * 销毁元素
		 */
		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			// TODO 自动生成的方法存根
			container.removeView((View) object);
			object = null;
		}

		
    }
   
}