我是 flutter 新手，如何在 gridview.count 中获取 onTap 命令

我试图使图像可点击，但我无法在 gridview.count 中获得 onTap 命令

 Widget buildBody() {
    return SafeArea(
        child: Container(
      padding: EdgeInsets.all(20.0),child: Column(
        children: <Widget>[
          Expanded(
              child: GridView.count(
            crossAxisCount: 2,padding: EdgeInsets.all(20),crossAxisspacing: 20,mainAxisspacing: 20,children: _products
                .map(((item) => Card(
                      child: Container(
                        decoration: BoxDecoration(
                            image: DecorationImage(
                                image: Image.asset(item.imageUrl),fit: BoxFit.fill)),),)))
                .toList(),)),],));
  }

这是我得到的图像列表

List<Product> _products = <Product>[
  Product("Özel Kesim Magnet","Özel Kesim Magnet","assets/icons/ökm.png"),Product("Kuşe Etiketler","kş","assets/icons/ke.png"),Product("Opak Etiketler","oe","assets/icons/oe.png"),Product("Şeffaf Etiketler","şe","assets/icons/şe.png"),Product("Kutu Kesim","ks","assets/icons/kk.png"),Product("Tam Kesim","tk","assets/icons/tk.png"),Product("Özel Kesim","ÖK","assets/icons/ök.png"),Product("Folyo Kesim","fk","assets/icons/fk.png")
];