How to remove extra padding around AppBar leading icon in Flutter

Question

In my Flutter app, I have this AppBar

Widget setAppBar(){
  return new AppBar(
    title: addAppBarTextWidget(\'Explore\'),
    elevation: 0.0,
    leading:          


        

Answer 1

Complete working workaround with some input from Adrian.

return Scaffold(
  key: _scaffoldKey,
  appBar: AppBar(
    titleSpacing: 0.0,
    title: Row(
      mainAxisAlignment: MainAxisAlignment.start,
      crossAxisAlignment: CrossAxisAlignment.center,
      children: <Widget>[
        IconButton(
          icon: Icon(Icons.menu),
          onPressed: () => _scaffoldKey.currentState.openDrawer(),
        ),
        Stack(
          alignment: Alignment.center,
          children: <Widget>[
            IconButton(
              icon: Icon(Icons.mail_outline),
              onPressed: _onClickNotification,
            ),
            Positioned(
              top: 12.0,
              right: 10.0,
              width: 10.0,
              height: 10.0,
              child: Container(
                decoration: BoxDecoration(
                  shape: BoxShape.circle,
                  color: AppColors.notification,
                ),
              ),
            )
          ],
        ),
        Expanded(
          child: Center(child: Text('test')),
        )
      ],
    ),
    automaticallyImplyLeading: false,
    centerTitle: true,
    actions: <Widget>[
      Row(
        children: <Widget>[
          Text('Online'),
          Switch(
            value: true,
            onChanged: (bool value) {},
          )
        ],
      )
    ],
  ),
  drawer: Drawer(
    child: _buildDrawer(),
  ),
  body: Container(
    color: Colors.orange,
  ),
);

Answer 2

You can't do this because it is a predefined widget. You can, however, do this:

appBar: AppBar(
  automaticallyImplyLeading: false, // Don't show the leading button
  title: Row(
    mainAxisAlignment: MainAxisAlignment.start,
    crossAxisAlignment: CrossAxisAlignment.center,
    children: <Widget>[
      IconButton(
        onPressed: () => Navigator.pop(context),
        icon: Icon(Icons.arrow_back, color: Colors.white),
      ),
      // Your widgets here
    ],
  ),
),

Where automaticallyImplyLeading: true hides the leading IconButton so you can add your own widgets.