Flutter 2 second shows error when page load and ater 2 secons successfully shows - image

Question

Hello Any One Flutter Expert here ?? plz help meee...what i want to make is Like Facebook photo viewer when user slides images and check is this like or not same i want in my code...
i made my code in that i come from listing page and when i tap on listing i can see full screen image.. and i Can slide(Scroll) images...
BUTTT when i comes first time on this screen which i code it show me some bugs on screen for 3,4 seconds...after that i can see the image plz help mee and show my error
Future<PhotoDetail> pagedetail() async {
sharedPreferences = await SharedPreferences.getInstance();
Map data = {
"AccessToken": sharedPreferences.getString("AccessToken"),
"CustomerId": sharedPreferences.getInt("CustomerId"),
"ImageId": indexx == null ? widget.images[widget.currentindex].photoId : indexx
};
print(data);
final http.Response response = await http.post(
Constants.CUSTOMER_WEBSERVICE_URL + "/photo/detail",
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(data),
);
var jsonResponse = json.decode(response.body);
if (response.statusCode == 200) {
print("Response status : ${response.statusCode}");
print("Response status : ${response.body}");
isLike = jsonResponse["IsLike"]; //here i saving value when api is run
print("iSLiked Value:" +isLike.toString()); // value is printing here
return PhotoDetail.fromJson(json.decode(response.body));
} else {
throw Exception('Failed to load data');
}
}
Future<PhotoDetail> _photoDetail;
#override
void initState() {
_photoDetail = pagedetail();
setState(() {
pagedetail(); //here is my api run when page is load
});
super.initState();
}
void pageChange(int index){ //this method is when i scroll page
setState(() {
pagedetail(); // api is call again and again
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
extendBodyBehindAppBar: true,
body: Stack(
children: <Widget>[
Container(
child:
Center(
child: PhotoViewGallery.builder(
itemCount: widget.images.length,
builder: (BuildContext context , int index) {
return PhotoViewGalleryPageOptions(
imageProvider:
NetworkImage(widget.images[index].photoPreviewImagePath),
maxScale: PhotoViewComputedScale.covered * 1.8,
minScale: PhotoViewComputedScale.contained * 1.0,
);
},
pageController: _pageController,
enableRotation: false,
scrollDirection: Axis.horizontal,
onPageChanged: pageChange,
loadingBuilder: (BuildContext context , ImageChunkEvent event){
return Center(child: CircularProgressIndicator(),);
},
)
)
),
Positioned(
bottom: 10,
left: 30,
right: 30,
child: (_photoDetail == null) ? Text("error")
: FutureBuilder<PhotoDetail>(
future: _photoDetail,
// ignore: missing_return
builder: (context , snapshot){
int like = snapshot.data.isLike;
int Slection = snapshot.data.selectedCount;
print("like ?????:" +like.toString());
print("Selection ????? :" + Slection.toString());
if (snapshot.hasData){
return Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: <Widget>[
InkWell(
child: InkWell(
Likes();
Fluttertoast.showToast(
msg: "Liked",
toastLength: Toast.LENGTH_SHORT,
gravity: ToastGravity.BOTTOM,
timeInSecForIosWeb: 1,
backgroundColor: Color(0xfff58634),
textColor: Colors.white,
fontSize: 16.0
);
},
child: Icon(Icons.thumb_up,size: 20,color: like == 1 ? Color(0xfff58634) : Colors.white),
),
),
InkWell(
child: Icon(Icons.comment,size: 20,color: Colors.white),
),
InkWell(
onTap: (){
_onShare();
},
child: Icon(Icons.share,size: 20,color: Colors.white,),
),
InkWell(
onTap: (){},
child: Icon(Icons.photo_album,size: 20,color: Slection == 0 ? Colors.white : Color(0xfff58634)),
),
InkWell(
onTap: (){
setState(() {
viewwholike();
});
},
child: Icon(Icons.card_giftcard,size: 20,color:
Colors.white,),
),
]
);
}
else {
Text("error");
}
},
),
),
],
),
);
}
ERROR::════════ Exception caught by widgets library
═══════════════════════════════════════════════════════
The following NoSuchMethodError was thrown building
FutureBuilder<PhotoDetail>(dirty, state:
_FutureBuilderState<PhotoDetail>#ef81b):
The getter 'isLike' was called on null.
Receiver: null
Tried calling: isLike
The relevant error-causing widget was:
FutureBuilder<PhotoDetail>
file:///C:/Users/Hello%20Devloper/AndroidStudioProjects/
September/PhotoGranth-
App/lib/CampaignSinglePhotos.dart:400:15
When the exception was thrown, this was the stack:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
#1 _CampaignSinglePhotosState.build.<anonymous closure>
(package:photogranth2020/CampaignSinglePhotos.dart:404:42)
#2 _FutureBuilderState.build
(package:flutter/src/widgets/async.dart:732:55)
#3 StatefulElement.build
(package:flutter/src/widgets/framework.dart:4619:28)
#4 ComponentElement.performRebuild
(package:flutter/src/widgets/framework.dart:4502:15)

Answer 1

Flutter tells you that data is not ready when you test snapshot.data.isLike.
You should test always at the beginning if snapshot.hasData, only after that you can make all you want.
Otherwise, if snapshot.hasData is false, simply return CircularProgressIndicator() .