myFile

   MaterialButton(
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(40),
            ),
            color: Colors.white,
            child: Text('Simple Pop Up'),
            onPressed: () async {
              await animated_dialog_box.showCustomAlertBox( 
              
              // You can change the animation which u=you want to use like
              // animated_dialog_box.showScaleAlertBox
              // animated_dialog_box.showInOutDailog
              // animated_dialog_box.showRotatedAlert
              
            
                  context: context,
                  firstButton: MaterialButton(
                    shape: RoundedRectangleBorder(
                      borderRadius: BorderRadius.circular(40),
                    ),
                    color: Colors.white,
                    child: Text('Ok'),
                    onPressed: () {
                      Navigator.of(context).pop();
                    },
                  ),
                  yourWidget: Container(
                    child: Text('This is my first package'),
                  ));
            },
          ),