DART

circular elevated button flutter

    //circular elevated button
              ElevatedButton(
                style: ElevatedButton.styleFrom(
                  shape: const CircleBorder(),
                ),
                onPressed: () {},
                child: const Icon(Icons.refresh),
              ),

circular elevated button flutter

style: ElevatedButton.styleFrom(
	shape: CircleBorder(),
),

circular button in flutter

Container(
                      width: 90,
                      height: 90,
                      child: RaisedButton(onPressed: (){
                      },
                        color: Colors.deepOrange,  
                        textColor: Colors.white,
                        shape: CircleBorder(side: BorderSide.none),
                        child: Text('Login',style: TextStyle(
                            fontSize: 20.0
                        ),
                        ),
                      ),
                    )