我有一个像这样的扩展小部件列:
return new Container(
child: new Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: <Widget>[
new Expanded(
flex: 1,
child: convertFrom,
),
new Expanded(
flex: 1,
child: convertTo,
),
new Expanded(
flex: 1,
child: description,
),
],
),
);
它是这样的:
convertFrom，包括一个TextField。当我点击这个文本框时，Android键盘就会出现在屏幕上。这会改变屏幕大小，所以小部件会像这样调整大小:
有没有办法让键盘“覆盖”屏幕，使我的列不调整大小?如果我不使用Expanded widgets，并为每个widget硬编码一个高度，这些widget就不会调整大小，但是当键盘出现时，我会得到一个黑黄条纹错误(因为没有足够的空间)。这也不是对所有屏幕尺寸都灵活。
我不确定这是android特有的还是flutter特有的。
特点:
打开键盘时，背景图像不会调整大小
能够滚动隐藏在键盘后面的元素
import 'package:flutter/material.dart';
SizedBox addPaddingWhenKeyboardAppears() {
final viewInsets = EdgeInsets.fromWindowPadding(
WidgetsBinding.instance!.window.viewInsets,
WidgetsBinding.instance!.window.devicePixelRatio,
);
final bottomOffset = viewInsets.bottom;
const hiddenKeyboard = 0.0; // Always 0 if keyboard is not opened
final isNeedPadding = bottomOffset != hiddenKeyboard;
return SizedBox(height: isNeedPadding ? bottomOffset : hiddenKeyboard);
}
/// The size of the screen.
class ScreenSizeService {
final BuildContext context;
const ScreenSizeService(
this.context,
);
Size get size => MediaQuery.of(context).size;
double get height => size.height;
double get width => size.width;
}
class LoginPage extends StatelessWidget {
final _imageUrl =
'https://images.unsplash.com/photo-1631823460501-e0c045fa716f?ixid=MnwxMjA3fDB8MHxlZGl0b3JpYWwtZmVlZHwyNHx8fGVufDB8fHx8&ixlib=rb-1.2.1&auto=format&fit=crop&w=500&q=60';
const LoginPage({Key? key}) : super(key: key);
@override
Widget build(BuildContext context) {
final screenWidth = ScreenSizeService(context).width;
final screenHeight = ScreenSizeService(context).height;
return Scaffold(
resizeToAvoidBottomInset: false,
body: Container(
decoration: BoxDecoration(
image: DecorationImage(
image: NetworkImage(_imageUrl),
fit: BoxFit.cover,
),
),
child: SingleChildScrollView(
child: ConstrainedBox(
constraints: BoxConstraints(
minWidth: screenWidth,
minHeight: screenHeight,
),
child: Column(
children: [
...List.generate(6, (index) {
return Column(
children: [
Container(
height: 60,
width: double.maxFinite,
color: Colors.pink[100],
child: Center(child: Text('$index')),
),
const SizedBox(height: 40),
],
);
}),
Container(color: Colors.white, child: const TextField()),
addPaddingWhenKeyboardAppears(),
],
),
),
),
),
);
}
}
这是一个完美的解决方案，使您能够在SingleChildScrollView中拥有一个全屏列。这可以让你为所有屏幕大小创建一个完美的布局+有一个可滚动的屏幕，只有当你打开键盘或屏幕在呈现后溢出时才滚动(例如文本输入字段验证)
class PerfectFullScreen extends StatelessWidget {
const PerfectFullScreen({Key key}) : super(key: key);
@override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
backgroundColor: Theme.of(context).backgroundColor,
appBar: AppBar(),
body: Builder(
builder: (context) => SingleChildScrollView(
child: ConstrainedBox(
constraints: BoxConstraints(
minHeight: MediaQuery.of(context).size.height -
(MediaQuery.of(context).padding.top + kToolbarHeight)),
child: IntrinsicHeight(
child: Column(
children: [
Container(
height: randomImageHeight,
child: Image.asset(
"assets/images/change_password.png",
fit: BoxFit.cover,
),
),
Expanded(
child: WidgetThatShouldTakeRemainingSpace() )
],
)))),
),
));
}
}
重要的部分是带有正确BoxConstraints和InstrinsicHeight小部件的ConstrainedBox。
PS: MediaQuery.of .padding(上下文)。top + kToolbarHeight) == Appbar的高度
