android 入门学习笔记attr.xml TypedArray obtainStyledAttributes 使用

 需要引入

import android.content.res.Resources;
import android.content.res.TypedArray;

obtainStyledAttributes 作用就是从我们自己定义的attr.xml读取所需信息

 public class ImageAdapter extends BaseAdapter
  {
    int mGalleryItemBackground;
    private Context mContext;
    private Integer[] myImageIds;
    
    public ImageAdapter(Context c, Integer[] aid)
    {
      mContext = c;
      myImageIds = aid;
      TypedArray a = obtainStyledAttributes(R.styleable.Gallery);
      mGalleryItemBackground = a.getResourceId
      (
        R.styleable.Gallery_android_galleryItemBackground, 0
      );
      a.recycle();
    }
    
    @Override
    public int getCount()
    {
      // TODO Auto-generated method stub
      return myImageIds.length;
    }
    
    @Override
    public Object getItem(int  position)
    {
      // TODO Auto-generated method stub
      return null;
    }

    @Override
    public long getItemId(int  position)
    {
      // TODO Auto-generated method stub
      return position;
    }

    @Override
    public View getView
    (int position, View convertView, ViewGroup parent)
    {
      // TODO Auto-generated method stub
      
      /*产生ImageView对象*/
      ImageView i = new ImageView(mContext);
      /*设置图片给imageView对象*/
      i.setImageResource(myImageIds[position]);
      /*重新设置图片的宽高*/
      i.setScaleType(ImageView.ScaleType.FIT_XY);
      /*重新设置Layout的宽高*/
      i.setLayoutParams(new Gallery.LayoutParams(138, 108));
      /*设置Gallery背景图*/
      i.setBackgroundResource(mGalleryItemBackground);
      /*返回imageView对象*/
      return i;
    }
  }