// Unhandled Exception: Null check operator used on a null value// - flutter

Question

When i click on camera icon in stack widget and also it is unable to update image it show this error.It also not upload image to database nor it chaange the url** [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: Null check operator used on a null value E/flutter (28471): #0 _profileState.geturl (package:ecommerce/Auth/profile.dart:25:59) E/flutter (28471): **
I want to update image but facing error please solve it..
Code For Imagepicker
Future image(BuildContext context) async{
showModalBottomSheet(
elevation: 5,
enableDrag: true,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(20),
topRight: Radius.circular(20),
),
),
context: context,
builder: (BuildContext context) {
return Container(
height: 200,
child: Column(
children: [
///Gallery
ListTile(
leading: Icon(Icons.browse_gallery),
title: Text("Pick image from gallery"),
onTap: () async{
final gallery=await ImagePicker().pickImage(source: ImageSource.gallery);
if (gallery!=null) {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("Image Picked successfull",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
} else {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("Please pick image for further proccess",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
}
Code For updating Url
Future geturl(context)async{
final id=DateTime.now().toString();
final reference=FirebaseFirestore.instance.collection("user3");
await image(context);
final storage.Reference ref =
storage.FirebaseStorage.instance.ref('/images'+id);
final storage.UploadTask uploadTask = ref.putFile(_image!.absolute);
await Future.value(uploadTask);
final downurl=await ref.getDownloadURL();
print(FirebaseAuth.instance.currentUser!.uid);
reference.doc(FirebaseAuth.instance.currentUser!.uid).update(
{
"imageurl":downurl.toString(),
}
).then((value) {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("Updated successfully",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
}).catchError((e){
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("${e.message}",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
});
}
For displaying image in flutter app
Stack(
alignment: Alignment.bottomRight,
children: [
CircleAvatar(
radius: 70,
backgroundImage:_image!=null?FileImage(_image!.absolute) : NetworkImage(snapshot.data!.docs[index]["imageurl"]) as ImageProvider,
),
InkWell(
onTap: (){
geturl(context);
},
child: Icon(Icons.add_a_photo,size: 30,)),
],
),
Please solve I am facing this error for Last couple of days

Answer 1

You need to declare the image variable null by adding "?".
Example: DataType image?
Then display like this
image!=null ? CircleAvatar(
radius: 70,
backgroundImage: FileImage(_image!.absolute) ,
): CircleAvatar(
radius: 70,
backgroundImage: NetworkImage(snapshot.data!.docs[index]["imageurl"])

Answer 2

I think that this line is causing the problem:
final storage.UploadTask uploadTask = ref.putFile(_image!.absolute);
Because _image is probably null. Where do you assign a value to the variable _image?
EDIT:
how I would fix this:
you have one method pickImage that shows the bottom modal sheet and allows the user to pick an image. if the user picks an image, you call a method that saves the picked image to firebase, in this case the method is called: saveImage
void pickImage(BuildContext context) {
showModalBottomSheet(
elevation: 5,
enableDrag: true,
isDismissible: false,
shape: const RoundedRectangleBorder(
borderRadius: BorderRadius.only(
topLeft: Radius.circular(20),
topRight: Radius.circular(20),
),
),
context: context,
builder: (BuildContext context) {
return Container(
height: 200,
child: Column(
children: [
ListTile(
leading: Icon(Icons.browse_gallery),
title: Text("Pick image from gallery"),
onTap: () async {
XFile? pickedImage = await ImagePicker().pickImage(source: ImageSource.gallery);
if (pickedImage != null) {
ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
content: Text(
"Image Picked successfull",
style: TextStyle(color: Colors.redAccent),
),
duration: Duration(seconds: 5),
));
var image = Image.memory(await pickedImage.readAsBytes());
// save image to firebase
saveImage(context, image);
} else {
ScaffoldMessenger.of(context).showSnackBar(const SnackBar(
content: Text(
"Please pick image for further proccess",
style: TextStyle(color: Colors.redAccent),
),
duration: Duration(seconds: 5),
));
}
},
),
],
),
);
},
);
}
method that saves the image to firebase:
Future saveImage(context, _image) async {
final id = DateTime.now().toString();
final reference=FirebaseFirestore.instance.collection("user3");
final storage.Reference ref =
storage.FirebaseStorage.instance.ref('/images'+id);
final storage.UploadTask uploadTask = ref.putFile(_image!.absolute);
await Future.value(uploadTask);
final downurl=await ref.getDownloadURL();
print(FirebaseAuth.instance.currentUser!.uid);
reference.doc(FirebaseAuth.instance.currentUser!.uid).update(
{
"imageurl":downurl.toString(),
}
).then((value) {
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("Updated successfully",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
}).catchError((e){
ScaffoldMessenger.of(context).showSnackBar(SnackBar(
content: Text("${e.message}",style: TextStyle(color: Colors.redAccent),
),duration: Duration(seconds: 5),
));
});
}