<GridView
    android:id="@+id/gridview"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:numColumns="auto_fit"
    android:horizontalSpacing="5dp"
    android:verticalSpacing="5dp"
    android:columnWidth="70dp" />

public class MainActivity extends Activity {
    private GridView gridview;
    private int[] resIds = new int[] { R.drawable.img1, R.drawable.img2, R.drawable.img3, R.drawable.img4,
            R.drawable.img5, R.drawable.img6, R.drawable.img7, R.drawable.img8 };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        gridview = (GridView) findViewById(R.id.gridview);
        // 设置gridview显示的adapter
        MyAdapter adapter = new MyAdapter();
        gridview.setAdapter(adapter);
    }

    // 使用自定义的adapter
    class MyAdapter extends BaseAdapter {
        // 总共有多少元素
        @Override
        public int getCount() {
            return resIds.length;
        }

        // 每个元素的具体内容
        @Override
        public Object getItem(int position) {
            return resIds[position];
        }

        // 每个元素的id
        @Override
        public long getItemId(int position) {
            return position;
        }

        // 每个元素的视图
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View view = null;
            ViewHolder holder = null;
            if (convertView == null) {
                // 1. 从自定义布局中获取view
                LayoutInflater inflater = LayoutInflater.from(MainActivity.this);
                view = inflater.inflate(R.layout.item, null);
                // 2. 在view中找到imageview
                holder = new ViewHolder();
                holder.image = (ImageView) view.findViewById(R.id.imageview);
                // 3. 绑定view与holder
                view.setTag(holder);
            } else {
                // 1. 从convertView中找到view
                view = convertView;
                // 2. 从view中找到绑定的holder
                holder = (ViewHolder) view.getTag();
            }
            // 4. 给holder中的内容设置值
            Bitmap bitmap = BitmapFactory.decodeResource(getResources(), resIds[position]);
            holder.image.setImageBitmap(bitmap);
            // 5. 返回view
            return view;
        }

        class ViewHolder {
            public ImageView image;
        }

    }
}