How to make a style widget on ShowDialog?

Question

question:

I have finished the rest of the dialog, but the top side has a round overflow avatar. I don’t know how to do it now. As shown in this picture

demo picture

Answer 1

You need to create a Home Screen Widget to call a function showDialog in any button, when Pressed or Tap, passing the arguments that you need, like QRCode Image and Avatar.

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: FlatButton(
          color: Colors.blue,
          child: Text("My Dialog"),
          onPressed: () => {
            showDialog(
              context: context,
              barrierDismissible: true,
              builder: (BuildContext context) => MyDialog(),
            ),
          },
        ),
      ),
    );
  }
}

Finally create its Dialog Class and use Stack and Positioned to put Avatar on top of Dialog Content.

class MyDialog extends StatelessWidget {
  MyDialog({
    Key key,
    // Something you need like a QRCode and Avatar Image
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    double radius = 50;
    double padding = 10;
    double hSize = 400;
    double wSize = 400;

    return Dialog(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(10),
      ),
      elevation: 0.0,
      backgroundColor: Colors.transparent,
      child: Container(
        width: 400,
        child: Stack(
          children: <Widget>[
            Container(
              padding: EdgeInsets.all(padding),
              margin: EdgeInsets.only(top: radius),
              decoration: new BoxDecoration(
                color: Colors.white,
                borderRadius: BorderRadius.circular(padding),
              ),
              height: hSize,
              width: wSize,
            ),
            Positioned(
              left: padding,
              right: padding,
              child: CircleAvatar(
                backgroundColor: Colors.indigo,
                radius: radius,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

This is Result:

Answer 2

Can be solved with the Badges plugin. Wrap the QRCode with Badge and modify the position parameter which is a BadgePosition to the exact top and left values.

Badge(
      position: BadgePosition.topLeft(top: 0,left: 0),//change this to get the right location
      badgeContent: YourAvatar(),
      child: YourQRImage(),
       
    )