How to group photos by time in Flutter? - flutter

Question

I want the photos taken on the same date to be in the same group.
This is my gallery
I want this
Future<List<VideoImageDataModel>> fetchPhotos() async {
var dataList = await Historydao().ImageData();
return dataList;
}
FutureBuilder<List<VideoImageDataModel>>(
future: fetchPhotos(),
builder: (context, snapshot) {
if (snapshot.hasData) {
var photoList = snapshot.data;
return GridView.builder(
gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
childAspectRatio: (10 / 10), crossAxisCount: 4),
itemCount: photoList?.length,
itemBuilder: (BuildContext context, int index) {
return Container(
margin: EdgeInsets.fromLTRB(5, 5, 0, 0),
//padding: EdgeInsets.fromLTRB(10, 5, 0, 0),
child: Hero(
tag: photoList![index].thumbnail,
child: GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => ImagePage(
photoList[index]
.thumbnail
.toString())));
},
child: Stack(fit: StackFit.expand,
children: [
Image.file(
fit: BoxFit.cover,
File(photoList[index].thumbnail.toString()),
),
Positioned(
right: 3,
bottom: 3,
child: Column(crossAxisAlignment: CrossAxisAlignment.end,
children: [
Text(
'${DateFormat('Hm', 'en_US').format(DateTime.fromMillisecondsSinceEpoch(photoList[index].id))}',
style: const TextStyle(
color: Colors.white,
fontSize: 9,
fontWeight: FontWeight.bold),
),
Text(
'${DateFormat('dd/MM/yyyy').format(DateTime.fromMillisecondsSinceEpoch(photoList[index].millisecond))}',
style: TextStyle(
color: Colors.white,
fontSize: 9,
fontWeight: FontWeight.bold),
), ],),),],),),),);}, );
} else {
return const Center(
child: CircularProgressIndicator(
color: Colors.blue,
),
);
}
},
),
I am creating my gallery using gridview builder.Thumbnail is photo name.I am generating date data using milliseconds.I want to show photos taken on the same day as a group.I can find the changed date using for loop.i don't know how to do this.