Flutter/UI

body内に複数行textを表示

body: Center(
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
           Text(
             'hello',
           ),
           Text(
             '$_counter',
             style: Theme.of(context).textTheme.display1,
           ),
           RaisedButton(
             child: Text('Back to MyPage 1'),
             onPressed: () {
               Navigator.pop(context);
             },
           ),
         ],
       ),
),

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),
     ),
);

入力フォーム

TextFormField(
             decoration: InputDecoration(
                 labelText: 'Enter your username'
             ),
),

複数行入力フォーム

Container(
             margin: EdgeInsets.all(8.0),
             // hack textfield height
             padding: EdgeInsets.only(bottom: 40.0),
             child: TextField(
               keyboardType: TextInputType.multiline,
               maxLines: 6,
               decoration: InputDecoration(
                 hintText: "テキストを作成",
                 border: OutlineInputBorder(),
               ),
               autofocus: true,
               onChanged: (text) {
                 // value = text;
               },
             ),
),

入力フォームにデフォルトで文字入力

 TextEditingController _controller;
 @override
 void initState() {
   super.initState();
   // _controller = new TextEditingController(text: 'hogehoge'); // これでもよい
   _controller = new TextEditingController();
   _controller.text = "hogehoge";
 }
// 略
child: TextField(
               controller: _controller,
               keyboardType: TextInputType.multiline,
),

参考：https://stackoverflow.com/questions/43214271/how-do-i-supply-an-initial-value-to-a-text-field