Flutter/UI/Button

body内にボタンを表示

body: Center(
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
           Text(
             'hello',
           ),
           RaisedButton(
             child: Text('button1'),
             onPressed: () {
               // ボタン処理
             },
           ),
         ],
       ),
),

画面右下にボタンを表示

floatingActionButtonをScaffoldの項目に追加

return Scaffold(
     appBar: AppBar(
       title: Text(widget.title),
     ),
     body: Center(
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
           Text(
             'hello',
           ),
         ],
       ),
     ),
     floatingActionButton: FloatingActionButton(
       onPressed:() {
              // ボタン処理
            },
       tooltip: 'Increment',
       child: Icon(Icons.add),
     ),
);

上部バーの右にボタンを設置

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("$widget.title"),
        actions: _buildAppBarActionButton()
      ),
    );
  }
  List<Widget> _buildAppBarActionButton() {
    return
    <Widget>[
      MaterialButton(
        onPressed: () {
        },
        child: Text(
          "Setting",
          style: TextStyle(
              fontSize: 14.0,
              color: Colors.white
          ),
        ),
      )
    ];
  }