Scaffold(
  body: Container(
    color: Colors.white,
    child: Center(child: Text("Flutter"),),
  ),
  bottomNavigationBar: new Container(
    padding: EdgeInsets.all(0.0),
    child: Row(
      mainAxisSize: MainAxisSize.max,
      children: [

        Expanded(
          flex: 1,
          child: FlatButton.icon(
            onPressed: () {
            },
            icon: Icon(Icons.search),
            label: Text("Search"),
          ),
        ),
        Expanded(
          flex: 1,
          child: FlatButton.icon(
            onPressed: () {
            },
            icon: Icon(Icons.search),
            label: Text("Search"),
          ),
        ),
        Expanded(
          flex: 1,
          child: FlatButton.icon(
            onPressed: () {
            },
            icon: Icon(Icons.search),
            label: Text("Search"),
          ),
        ),
      ],
    ),
  ),
);