android viewpager Android ViewPager相册横向移动的实现方法

public class ImageItem {
 private int id;// 资源id
 private String name;// 显示的名称
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public ImageItem(int id, String name) {
  super();
  this.id = id;
  this.name = name;
 }
 public int getId() {
  return id;
 }
 public void setId(int id) {
  this.id = id;
 }
}

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
　　android:layout_width="match_parent"
　　android:layout_height="match_parent" >

　　<ImageView
　　　　android:id="@+id/imgview"
　　　　android:layout_width="fill_parent"
　　　　android:layout_height="fill_parent"
　　　　android:contentDescription="@string/app_name"
　　　　android:scaleType="fitXY" />

　　<TextView
　　　　android:id="@+id/textView"
　　　　android:layout_width="wrap_content"
　　　　android:layout_height="wrap_content"
　　　　android:layout_gravity="bottom|center_horizontal" />

</FrameLayout>

public class ViewpagerItem extends FrameLayout {
 private ImageView imageview;// 显示图片的ImageView
 private TextView textview;
 private Bitmap bitmap;// 图片对应的Bitmap
 private ImageItem imageitem;// 每一个图片项对象

 public ViewpagerItem(Context context) {
  super(context);
  setViews();
 }
 public ViewpagerItem(Context context, AttributeSet attrs) {
  super(context, attrs);
  setViews();
 }

 public void setData(ImageItem item) {// 用ImageItem填充数据
  this.imageitem = item;
  int resid = item.getId();
  String name = item.getName();
  imageview.setImageResource(resid);
  textview.setText(name);
 }

 public void reload() {// 重新载入数据
  int resid = imageitem.getId();
  imageview.setImageResource(resid);
 }

 public void recycle() {// 回收数据
  imageview.setImageBitmap(null);
  if (this.bitmap == null || this.bitmap.isRecycled()) {
   return;
  }
  this.bitmap.recycle();
  this.bitmap = null;
 }

 public void setViews() {
  LayoutInflater infalter = LayoutInflater.from(getContext());
  View view = infalter.inflate(R.layout.pageritem, null);
  textview = (TextView) view.findViewById(R.id.textView);
  imageview = (ImageView) view.findViewById(R.id.imgview);

  addView(view);
 }
}

public class PagerItemAdapter extends PagerAdapter {
 private Context context;
 private ImageItem[] image;

 public PagerItemAdapter(Context context, ImageItem[] image) {
  this.context = context;
  this.image = image;
  hashMap = new HashMap<Integer, ViewpagerItem>();
 }

 private HashMap<Integer, ViewpagerItem> hashMap;// 保存相片的id以及对应的ViewpagerItem

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

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

 @Override
 public void finishUpdate(ViewGroup container) {
  super.finishUpdate(container);
 }

 @Override// 初始化一个ViewpagerItem，如果已经存在就重新载入，没有的话new一个
 public Object instantiateItem(ViewGroup container, int position) {
  ViewpagerItem item;
  if (hashMap.containsKey(position)) {
   item = hashMap.get(position);
   item.reload();
  } else {
   item = new ViewpagerItem(context);
   ImageItem itemimg = image[position];
   item.setData(itemimg);
   hashMap.put(position, item);
   ((ViewPager) container).addView(item);
  }
  return item;
 }

 @Override// 当我们左右滑动图片的时候会将图片回收掉
 public void destroyItem(View container, int position, Object object) {
  ViewpagerItem item = (ViewpagerItem) object;
  item.recycle();
 }
}

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

public class MainActivity extends Activity {
 private final static int RES[] = { R.drawable.p1, R.drawable.p2 };// p1,p2为drawable文件夹下的两张图片
 private ViewPager viewpager;
 private PagerItemAdapter adapter;
 private ImageItem[] item;

 private void setView(){
  item = new ImageItem[2];
  item[0] = new ImageItem(RES[0], "page1");
  item[1] = new ImageItem(RES[1], "page2");
  viewpager = (ViewPager) findViewById(R.id.viewpager);
  adapter = new PagerItemAdapter(getApplicationContext(), item);
  viewpager.setAdapter(adapter);
 }

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  setView();
 }
}