i have alot of similar containers in my app that hold varied pieces of text. I want to make a Dart Function that i can then use to return the container and the specify color and text height and width.

when I try to make the Dart Function:

Container MyContainer() {}

the MyContainer part is coming back with the error: The body might complete normally, causing 'null' to be returned, but the return type, 'Container', is a potentially non-nullable type

I've looked at the docs but don't understand how the common fixes would be implemented into the function.

cheers

CodePudding user response：

Just create a class extending StatelessWidget like this :

class MyCustomContainer extends StatelessWidget {
  const MyCustomContainer({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
      // Do what you want
    );
  }
}

Or you can also do it quickly as a getter Widget inside another class

Widget myCustomContainer() {
    return Container(
      // Do what you want
    );
  }

And just call it inside your tree in build()

CodePudding user response：

You have two options:

1.Use functions that return Container. For Example,

Container MyContainer({required Color color, required String label, double width = 200, double height = 300}) {
 return Container(
    height: height,
    width: width,
    decoration: BoxDecoration(
    color: color,
    ),
    child: Text(label),
 );
}

But that's not a correct way to create a Reusable Widget. The optimal way is:

2. Extract a custom StatelessWidget class for that widget. Like this.

class MyContainer extends StatelessWidget {
  const MyContainer({Key? key, this.width = 200, this.height = 300, required this.label, required this.color}) : super(key: key);
  final double width;
  final double height;
  final String label;
  final Color color;
  @override
  Widget build(BuildContext context) {
    return Container(
      width: width,
      height: height,
      decoration: BoxDecoration(
        color: color,
      ),
      child: Text(label),
    );
  }
}