How can I make transparent appbar?

return Scaffold(
  backgroundColor: Color(0xfff2edd7),
  appBar: AppBar(
    backgroundColor: Color(0x00000000),
    elevation: 0,
  ),
  drawer: _drawer(),
  body: SingleChildScrollView(
    child: Column(
      children: <Widget>[
        Stack(
          children: <Widget>[
            Container(
              height: size.height * 0.3+100,
              decoration: BoxDecoration(
                  gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      //stops: [0.1, 0.6, 1],
                      colors: [Color(0xff4165a4), Color(0xff6573a4), Color(0xffa28aa5),Color(0xffccaaa7),Color(0xfff2edd7)])),
            ),

This is my part of code, and I want to make the color of appbar change by the color of container which have gradient color.

If I locate the body part higher than the appbar part, Will it be solved?

Set backgroundColor as transparent

  appBar: new AppBar(
          backgroundColor: Colors.transparent,
          elevation: 0.0,
        ),