Google SignIn Button:

Widget _signInButton() {




   return OutlineButton(


     splashColor: Colors.grey,


     onPressed: () {},


     shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(40)),


     highlightElevation: 0,


     borderSide: BorderSide(color: Colors.grey),


     child: Padding(


       padding: const EdgeInsets.fromLTRB(0, 10, 0, 10),


       child: Row(


         mainAxisSize: MainAxisSize.min,


         mainAxisAlignment: MainAxisAlignment.center,


         children: <Widget>[


           Image(image: AssetImage("assets/google_logo.png"), height: 35.0),


           Padding(


             padding: const EdgeInsets.only(left: 10),


             child: Text(


               'Sign in with Google',


               style: TextStyle(


                 fontSize: 20,


                 color: Colors.grey,


               ),


             ),


           )


         ],


       ),


     ),


   );


 }