刚刚开始学习 Android，请问一下下面这两行代码为什么会导致闪退？

这样写就完全OK，应该是view.getTag() 没有正确返回ViewHolder对象

        mView = LayoutInflater.from(context).inflate(R.layout.grid_item,viewGroup,false);
        ImageView img  = (ImageView) mView.findViewById(R.id.icon_item);
        TextView title = (TextView) mView.findViewById(R.id.icon_text);

        img.setImageResource(arr.get(i).getRid());
        title.setText(arr.get(i).getTitle());

        return mView;

前面使用ListView,没有setTag,却能正常跑起来，所以我忽略了setTag这个api

            ViewHolder holder = null;
            if(view == null){
                holder = new ViewHolder();
                mView = LayoutInflater.from(context).inflate(R.layout.view_item,viewGroup,false);
                holder.title =  (TextView) mView.findViewById(R.id.title);
                holder.desc = (TextView) mView.findViewById(R.id.desc);
                holder.img = (ImageView) mView.findViewById(R.id.img);
            }else{
                holder =(ViewHolder)mView.getTag();
            }

            holder.title.setText(data.get(i).getTitle());
            holder.desc.setText(data.get(i).getDesc());
            holder.img.setImageResource(data.get(i).getIcon());

            return mView;