Android GridView拉伸行高

public class MyAdapter extends BaseAdapter {
    private Context mContext;
    private List<Item> mItems;

    public MyAdapter(Context context, List<Item> items) {
        mContext = context;
        mItems = items;
    }

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

    @Override
    public Object getItem(int position) {
        return mItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = LayoutInflater.from(mContext).inflate(R.layout.grid_item, parent, false);
            holder = new ViewHolder();
            holder.imageView = convertView.findViewById(R.id.image_view);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        Item item = mItems.get(position);
        holder.imageView.setImageResource(item.getImageResId());

        // 设置行高为GridView高度的一半
        int gridViewHeight = parent.getHeight();
        convertView.setLayoutParams(new GridView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, gridViewHeight / 2));

        return convertView;
    }

    private static class ViewHolder {
        ImageView imageView;
    }
}