本文实例讲述了Android编程UI设计之GridView和ImageView的用法。，具体如下：
GridView: A view that shows items in two-dimensional scrolling grid. The items in the grid come from the ListAdapter associated with this view. 简单说，GridView就是我们资源管理器平常见到的一个个文件的icon显示方式。
上面提及到了，GridView的Item是来自ListAdapter的，所以一般在Activity的onCreate使用GridView的代码：
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.grid_2);
GridView g = (GridView) findViewById(R.id.myGrid);
g.setAdapter(new ImageAdapter(this));
}
而ImageAdapter一般是extends BaseAdapter。BaseAdapter是implements ListAdapter SpinnerAdapter，但很多时候自定义的Adapter都是override ListAdapter的父类Adapter接口里面的方法：
int getCount() 获取当前Adapter的Items数目
Object getItem(int position) 获取相应position的Item
long getItemId(int position) 获取相应position的Item在List中的row id
View getView(int position, View convertView, ViewGroup parent) 获取在指定position所要显示的data的View
这些方法函数和swing的差不多，都是基于MVC。大概原理过程是这样的：程序需要显示GridView，那么要把data一个一个地显示出来是通过一个for循环，首先call Adapter.getCount()得到有多少个data，然后position++地getItem，getView得到要显示的view,这样子逐一地显示出来！
下面是官方sample里面的Photo Grid的例子，本人省略了某些代码：
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(45, 45));//设置ImageView宽高
imageView.setAdjustViewBounds(false);
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(mThumbIds[position]);
return imageView;
}
private Context mContext;
private Integer[] mThumbIds = {
R.drawable.sample_thumb_0, R.drawable.sample_thumb_1,
R.drawable.sample_thumb_2, R.drawable.sample_thumb_3,
R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
R.drawable.sample_thumb_6, R.drawable.sample_thumb_7
};
}
