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

落日映苍穹つ 2021-09-12 03:22 280阅读 0赞

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;
        }
      }