android仿Adapter实现自定义PagerAdapter方法示例

private class ViewPagerAdapter extends PagerAdapter { 
 
    // 获取要滑动的控件的数量，在这里我们以滑动的广告栏为例，那么这里就应该是展示的广告图片的ImageView数量 
    @Override 
    public int getCount() { 
      return images.size(); 
    } 
 
    // 来判断显示的是否是同一张图片，这里我们将两个参数相比较返回即可 
    @Override 
    public boolean isViewFromObject(View arg0, Object arg1) { 
      return arg0 == arg1; 
    } 
 
    // PagerAdapter只缓存三张要显示的图片，如果滑动的图片超出了缓存的范围，就会调用这个方法，将图片销毁 
    @Override 
    public void destroyItem(ViewGroup view, int position, Object object) { 
      view.removeView(images.get(position)); 
    } 
 
    // 当要显示的图片可以进行缓存的时候，会调用这个方法进行显示图片的初始化，我们将要显示的ImageView加入到ViewGroup中，然后作为返回值返回即可 
    @Override 
    public Object instantiateItem(ViewGroup view, int position) { 
      view.addView(images.get(position)); 
      return images.get(position); 
    } 
  } 

public abstract class EjBasePagerAdapter<T> extends PagerAdapter {

 protected List<T> list;
 protected SparseArray<EjBasePagerHolder<T>> sparseArray;

 public EjBasePagerAdapter(List<T> list){
  this.list = list;
  sparseArray = new SparseArray<>();
 }

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

 public String getIcon(int position){
  return null;
 }

 @Override
 public Object instantiateItem(ViewGroup container, int position) {
  EjBasePagerHolder<T> holder = sparseArray.get(getSparsePosition(position));
  if(null == holder){
   holder = onBundHolder(container);
   holder.setPosition(position);
   holder.bindDada(list.get(position),position);
   sparseArray.put(getSparsePosition(position),holder);
  }
  View view = holder.itemView;
  container.addView(view);
  return view;
 }

 @Override
 public void notifyDataSetChanged() {
  sparseArray.clear();
  super.notifyDataSetChanged();
 }

 protected int getSparsePosition(int position){
  return (position+10)*2;
 }

 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {
  container.removeView((View) object);
 }

 protected View inflate(int resorce, ViewGroup viewGroup) {
  return LayoutInflater.from(viewGroup.getContext()).inflate(resorce, viewGroup, false);
 }

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

 protected abstract EjBasePagerHolder<T> onBundHolder(ViewGroup container);

 public void onDestroy(){

 }

 public void onActivityResult(int requestCode, int resultCode, Intent data) {

 }

 protected abstract class EjBasePagerHolder<D>{
  /**上下文*/
  protected Context mContext;
  private int position;

  SparseArray<View> sparseArray;
  View itemView;

  protected EjBasePagerHolder(View itemView){
   this.itemView = itemView;
   this.mContext = itemView.getContext();
   sparseArray = new SparseArray<>();
   initView();
  }

  public abstract void initView();

  public View findViewById(int id){
   View view = sparseArray.get(id);
   if(null == view){
    view = itemView.findViewById(id);
    sparseArray.append(id,view);
   }
   return view;
  }

  public abstract void bindDada(D t,int position);

  public void onActivityResult(int requestCode, int resultCode, Intent data) {

  }

  public void setPosition(int position) {
   this.position = position;
  }

  public int getPosition() {
   return position;
  }

  public void onDestroy(){
   sparseArray.clear();
  }
 }
}

public class EjMainFmtBannerPagerAdapter extends EjBasePagerAdapter<EjMainFragmentDataBean>{

 public EjMainFmtBannerPagerAdapter(List<EjMainFragmentDataBean> list) {
  super(list);
 }

 @Override
 protected EjBasePagerHolder<EjMainFragmentDataBean> onBundHolder(ViewGroup container) {
  return new EjBasePagerHolder<EjMainFragmentDataBean>(LayoutInflater.from(container.getContext()).inflate(R.layout.ejmain_item_fmt_banner,null)) {

   private ImageView ejmain_iv_banner;

   @Override
   public void initView() {
    ejmain_iv_banner = (ImageView)findViewById(R.id.ejmain_iv_banner);
   }

   @Override
   public void bindDada(EjMainFragmentDataBean t, int position) {
    GlidUtil.loadUrl(t.img1,ejmain_iv_banner,mContext);
   }
  };
 }
}