Uploading Screenshots to Firebase with Flutter - flutter

Question

I want to upload the screenshot image to Firestore, but I am having some null errors,
Future uploadImagetoFirebase() async {
await screenshotController.capture().then((value) => (File image) {
_screenshot = image;
});
String fileName = _screenshot.path;
Reference firebaseStorageRef =
FirebaseStorage.instance.ref().child('orders/$fileName');
UploadTask uploadTask = firebaseStorageRef.putFile(_screenshot);
TaskSnapshot taskSnapshot = await uploadTask;
taskSnapshot.ref.getDownloadURL().then((value) => print('Done: $value'));
}
I am calling it with button like this:
onPressed: () async {
await uploadImagetoFirebase(); }
This is the error stack:
flutter ( 5143): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: NoSuchMethodError: The getter 'path' was called on null.
E/flutter ( 5143): Receiver: null
E/flutter ( 5143): Tried calling: path
E/flutter ( 5143): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
E/flutter ( 5143): #1 _CartState.uploadImagetoFirebase
package:CWCFlutter/model/cart.dart:88
E/flutter ( 5143): <asynchronous suspension>
E/flutter ( 5143): #2 _CartState.build.<anonymous closure>.<anonymous closure>.<anonymous closure>.<anonymous closure>
package:CWCFlutter/model/cart.dart:310
E/flutter ( 5143): #3 _InkResponseState._handleTap
package:flutter/…/material/ink_well.dart:993
E/flutter ( 5143): #4 _InkResponseState.build.<anonymous closure>
package:flutter/…/material/ink_well.dart:1111
E/flutter ( 5143): #5 GestureRecognizer.invokeCallback
package:flutter/…/gestures/recognizer.dart:183
E/flutter ( 5143): #6 TapGestureRecognizer.handleTapUp
package:flutter/…/gestures/tap.dart:598
E/flutter ( 5143): #7 BaseTapGestureRecognizer._checkUp
package:flutter/…/gestures/tap.dart:287
E/flutter ( 5143): #8 BaseTapGestureRecognizer.handlePrimaryPointer
package:flutter/…/gestures/tap.dart:222
E/flutter ( 5143): #9 PrimaryPointerGestureRecognizer.handleEvent
package:flutter/…/gestures/recognizer.dart:476
E/flutter ( 5143): #10 PointerRouter._dispatch
package:flutter/…/gestures/pointer_router.dart:77
E/flutter ( 5143): #11 PointerRouter._dispatchEventToRoutes.<anonymous closure>
package:flutter/…/gestures/pointer_router.dart:122
E/flutter ( 5143): #12 _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:377:8)
E/flutter ( 5143): #13 PointerRouter._dispatchEventToRoutes
package:flutter/…/gestures/pointer_router.dart:120
E/flutter ( 5143): #14 PointerRouter.route
package:flutter/…/gestures/pointer_router.dart:106
E/flutter ( 5143): #15 GestureBinding.handleEvent
package:flutter/…/gestures/binding.dart:358
E/flutter ( 5143): #16 GestureBinding.dispatchEvent
package:flutter/…/gestures/binding.dart:338
E/flutter ( 5143): #17 RendererBinding.dispatchEvent
package:flutter/…/rendering/binding.dart:267
E/flutter ( 5143): #18 GestureBinding._handlePointerEvent
package:flutter/…/gestures/binding.dart:295
E/flutter ( 5143): #19 GestureBinding._flushPointerEventQueue
package:flutter/…/gestures/binding.dart:240
E/flutter ( 5143): #20 GestureBinding._handlePointerDataPacket
package:flutter/…/gestures/binding.dart:213
E/flutter ( 5143): #21 _rootRunUnary (dart:async/zone.dart:1206:13)
E/flutter ( 5143): #22 _CustomZone.runUnary (dart:async/zone.dart:1100:19)
E/flutter ( 5143): #23 _CustomZone.runUnaryGuarded (dart:async/zone.dart:1005:7)
E/flutter ( 5143): #24 _invoke1 (dart:ui/hooks.dart:265:10)
E/flutter ( 5143): #25 _dispatchPointerDataPacket (dart:ui/hooks.dart:174:5)
I am not sure how path was called on null, any ideas? Basically I await for the app to take a screenshot, then add that image in _screenshot File variable, then try to store it in 'orders' folder in Firestore. I have searched for answers, and they say you need to initialize Firestore somewhere, but I am not sure where that would be, I have only worked with older versions, and not sure how to do all things in the newer ones. Thank you!
I have tried setting the state as well, but getting the same error:
Future uploadImagetoFirebase() async {
await screenshotController.capture().then((value) => (File image) {
setState(() {
_screenshot = image;
});
});
What I came up with that seems to work as a solution
Future<String> uploadImagetoFirebase2() async {
File img = await screenshotController.capture();
setState(() {
_screenshot = img;
});
//change filename not to be path, but something else short
String fileName = img.path;
Reference firebaseStorageRef =
FirebaseStorage.instance.ref().child('orders/$fileName');
UploadTask uploadTask = firebaseStorageRef.putFile(_screenshot);
TaskSnapshot taskSnapshot = (await uploadTask);
String uri = await taskSnapshot.ref.getDownloadURL();
print(uri);
return uri;
}

Answer 1

flutter ( 5143): [ERROR:flutter/lib/ui/ui_dart_state.cc(177)] Unhandled Exception: NoSuchMethodError: The getter 'path' was called on null.
E/flutter ( 5143): Receiver: null
E/flutter ( 5143): Tried calling: path
your path is null,
you can solve this in two ways
1. setstate
Future uploadImagetoFirebase() async {
await screenshotController.capture().then((value) => (File image) {
setState(() {
_screenshot = image;
});
});
//... your fireabase upload function
2 return from future
Future <File> uploadImagetoFirebase() async {
File myImage=await screenshotController.capture();
retun myImage
);
//get image onPress btn
onPressed: () async {
var myFile= await uploadImagetoFirebase();
//check if path is null using if ...
print(myFile.path);
// firebase function
Reference firebaseStorageRef =
FirebaseStorage.instance.ref().child('orders/${myFile.path}');
UploadTask uploadTask = firebaseStorageRef.putFile(myFile);
TaskSnapshot taskSnapshot = (await uploadTask);
String uri = await taskSnapshot.ref.getDownloadURL();
print(uri);
return uri;
}

Answer 2

try this;
Future<String> uploadImagetoFirebase() async {
File img = await screenshotController.capture();
String fileName = img.path;
Reference firebaseStorageRef =
FirebaseStorage.instance.ref().child('orders/$fileName');
UploadTask uploadTask = firebaseStorageRef.putFile(_screenshot);
TaskSnapshot taskSnapshot = (await uploadTask);
String uri = await taskSnapshot.ref.getDownloadURL();
print(uri);
return uri;
}