Flutter: Can't get File from ChangeNotifier

Question

I am trying to learn provider in flutter. But I am facing a problem. I want to get File _image from ChangeNotifier But it's showing me error.

Here is ChangeNotifierProvider

class ImagePicker extends ChangeNotifier {
  File _image;
  final picker = ImagePicker();

  Future getImage({ImageSource source}) async {
    final pickedFile = await picker.getImage(source: ImageSource.gallery);

    if (pickedFile != null) {
      _image = File(pickedFile.path);
    } else {
      print('No image selected.');
    }
    notifyListeners();
  }
}

and here is HomeScreen where I want to get that _image file.

class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Hello"),
      ),
      body: Container(
        child: Column(
          children: [
            Text("Select a image"),
            Image.file(Provider.of<ImagePicker>(context)._image),
            IconButton(
                icon: Icon(Icons.camera),
                onPressed: () {
                  Provider.of<ImagePicker>(context).getImage();
                })
          ],
        ),
      ),
    );
  }
}

It's showing me - The getter '_image' isn't defined for the type 'ImagePicker'. Try importing the library that defines '_image', correcting the name to the name of an existing getter, or defining a getter or field named '_image'.

Please some help me for fix this error. And explain what's happening.

_image means this variable is private. you can't use it outside. — ikerfah, Nov 03 '20 at 13:57
just remove the underscore :D or define a getter that return the value of ```_image``` — ikerfah, Nov 03 '20 at 14:04

score 2 · Answer 1 · answered Nov 03 '20 at 14:10

Change File _image variable to File image since _image means is a private variable. Something like this:

class ImagePicker extends ChangeNotifier {
File image;
final picker = ImagePicker();
Future getImage({ImageSource source}) async {
final pickedFile = await picker.getImage(source: ImageSource.gallery);

if (pickedFile != null) {
  this.image = File(pickedFile.path);
} else {
  print('No image selected.');
}
notifyListeners();
}}

score 1 · Accepted Answer · answered Nov 03 '20 at 14:06

So as discussed in the comments, any variable underscore prefix means this variable is private. So you have two solutions :

Delete underscore from _image and the variable will be accessible from outside the class.
Define getter that return _image value.

score 0 · Answer 3 · answered Nov 03 '20 at 14:05

0

Ohh, I solved this change _image to image. thanks @ikerfah

answered Nov 03 '20 at 14:05

Abir Ahsan

2,649
29
51

Flutter: Can't get File from ChangeNotifier

3 Answers3