Adjusting the grid layout - flutter

Question

I have been trying to add the code below within the card grid view. The text widget is just for testing purposes. When I tap on the card I want to perform the action that is written for the iconButton onPressed method.
Expanded(
child: StreamBuilder(
stream:
FirebaseFirestore.instance.collection('location').snapshots(),
builder: (context, AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) {
return Center(child: CircularProgressIndicator());
}
return ListView.builder(
itemCount: snapshot.data?.docs.length,
itemBuilder: (context, index) {
return ListTile(
title:
Text(snapshot.data!.docs[index]['name'].toString()),
subtitle: Row(
children: [
Text(snapshot.data!.docs[index]['latitude']
.toString()),
SizedBox(
width: 20,
),
Text(snapshot.data!.docs[index]['longitude']
.toString()),
],
),
trailing: IconButton(
icon: Icon(Icons.directions),
onPressed: () {
Navigator.of(context).push(MaterialPageRoute(
builder: (context) =>
MyMap(snapshot.data!.docs[index].id)));
},
),
);
});
},
)),
Here is the card grid
return Scaffold(body: Container(decoration: BoxDecoration(
image:DecorationImage(
image: AssetImage("assets/background.jpg"), fit: BoxFit.cover),),child: Container(
margin: const EdgeInsets.only(top: 120.0),
child: GridView(
physics: BouncingScrollPhysics(),
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),
children: events.map((title){
return GestureDetector(
child: Card(
elevation: 0,
color: Colors.transparent,
margin: const EdgeInsets.all(13.0),
child: getCardByTile(title)
),
onTap: () {
Fluttertoast.showToast(msg: title);
},
);
}).toList(),
),
),));
Here is the CardByTile() method used above.
getCardByTile(String title) {
String img = "";
if(title == "Navigation") {
img = "assets/navi.png";
}
if(title == "Current location") {
img = "assets/currentloc.png";
}
if(title == "Enable live location") {
img = "assets/track.png";
}
if(title == "Stop live location") {
img = "assets/stoplive.png";
}
return Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Center(
child: new Stack(
children: <Widget>[
new Image.asset(
img,
fit: BoxFit.contain,
//width: 80.0,
//height: 80.0,
)
],
),
)
]
);
}
and the event list.
List<String> events = [
"Navigation",
"Current location",
"Enable live location",
"Stop live location"
];