I want to have an IconButton below title of an AppBar. I tried Column, but I had problem with center all items there and with overflowing bottom.
My Code:
appBar: new AppBar( title: Column( children: <Widget>[ new Text('App Title'), IconButton( icon: new Icon(new IconData(0xe902, fontFamily: 'Ionicons')), onPressed: () {}, ) ], ), centerTitle: true, actions: <Widget>[ IconButton( icon: new Icon(new IconData(0xe906, fontFamily: 'Ionicons')), onPressed: () {}, ) ], ), You can try this
appBar: AppBar( centerTitle: true, title: Column( mainAxisAlignment: MainAxisAlignment.center, children: <Widget>[ Text("App Title"), GestureDetector( child: Icon(Icons.keyboard_arrow_down), onTap: () { // handle your click here }, ) ], ), ), Screenshot: 
Possible duplicate of this. Maybe you can try to reduce the sizes of your Text & IconButton widgets to avoid overflow (it won't look good) and add crossAxisAlignment: CrossAxisAlignment.center in your Column widget to center the Column's children in it's cross axis.
If none of that will work, maybe you can build your own appbar widget since everything is a widget on flutter..
