App Bar 

appBar:  AppBar(  //  is the bar at the top of the screen so you can control its properties
  leading: Padding(
    padding: EdgeInsets.all(1),
    child: Row(
      children: [
        IconButton(onPressed: (){}, icon: Icon(Icons.add_a_photo)),
        Expanded(child: IconButton(onPressed: (){}, icon: Icon(Icons.account_balance))),
      ],
    ),
  ),
  actions: [
    IconButton(onPressed: (){}, icon: Icon(Icons.ac_unit_sharp)),
    IconButton(onPressed: (){}, icon: Icon(Icons.where_to_vote)),
  ],
  flexibleSpace:
  Container(
    decoration: BoxDecoration(
      gradient: LinearGradient(
          colors: [
            Colors.deepOrangeAccent,
            Colors.amberAccent,
            Colors.orangeAccent
          ]
      ),
    ),
  ),
  centerTitle: true,
  title: const Text("Demo"),
),