Compose an animation and move your TextField container up when a TextField gets focus.
For learning about composing animations refer to:
Composing Animations and Chaining Animations in Dart's Flutter Framework
Use Flutter's FocusNode to detect the focus on a TextField
Edit:
Here I've written an example that does exactly what you want:
import 'package:flutter/material.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Animation Demo',
theme: new ThemeData(
primaryColor: new Color(0xFFFF0000),
),
home: new FormDemo(),
);
}
}
class FormDemo extends StatefulWidget {
@override
_FormDemoState createState() => _FormDemoState();
}
class _FormDemoState extends State<FormDemo> with SingleTickerProviderStateMixin {
AnimationController _controller;
Animation _animation;
FocusNode _focusNode = FocusNode();
@override
void initState() {
super.initState();
_controller = AnimationController(vsync: this, duration: Duration(milliseconds: 300));
_animation = Tween(begin: 300.0, end: 50.0).animate(_controller)
..addListener(() {
setState(() {});
});
_focusNode.addListener(() {
if (_focusNode.hasFocus) {
_controller.forward();
} else {
_controller.reverse();
}
});
}
@override
void dispose() {
_controller.dispose();
_focusNode.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
resizeToAvoidBottomPadding: false, // this avoids the overflow error
appBar: AppBar(
title: Text('TextField Animation Demo'),
),
body: new InkWell( // to dismiss the keyboard when the user tabs out of the TextField
splashColor: Colors.transparent,
onTap: () {
FocusScope.of(context).requestFocus(FocusNode());
},
child: Container(
padding: const EdgeInsets.all(20.0),
child: Column(
children: <Widget>[
SizedBox(height: _animation.value),
TextFormField(
decoration: InputDecoration(
labelText: 'I move!',
),
focusNode: _focusNode,
)
],
),
),
),
);
}
}
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…