Flutter-如何制作具有固定高度的自定义圆形选项卡指示器? [英] Flutter - How to make custom rounded shape tab indicator with fixed height?
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问题描述
我想制作一个圆形的指示器,如下图所示.
I want to make an indicator with a rounded shape like the below image.
我为此做了很多尝试,但是我无法使其形状像设计一样.
I tried a lot for it but I can't make it a shape like a design.
并且还告诉我如何使颤动的部分可扩展listview吗? 为列表视图设计
And also tell me how to make sectional expandable listview with flutter? Design for listview
推荐答案
具有圆形形状的自定义指标
您可以使用CustomPainer
Custom indicator with a rounded shape
You can use the CustomPainer
final Paint paint = Paint();
paint.color = Color(0xff1967d2);
paint.style = PaintingStyle.fill;
canvas.drawRRect(
RRect.fromRectAndCorners(rect,
topRight: Radius.circular(8), topLeft: Radius.circular(8)),
paint);
在此处中观看现场演示.
完成下面给出的示例代码.
Complete sample code given below.
import 'package:flutter/material.dart';
final Color darkBlue = Color.fromARGB(255, 18, 32, 47);
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark().copyWith(scaffoldBackgroundColor: darkBlue),
debugShowCheckedModeBanner: false,
home: DefaultTabController(
length: 4,
child: Scaffold(
appBar: AppBar(
centerTitle: true,
title: Text("Demo page", style: TextStyle(
color: Colors.black87
),),
backgroundColor: Colors.white,
bottom: TabBar(
labelStyle: TextStyle(
fontWeight: FontWeight.w700
),
indicatorSize: TabBarIndicatorSize.label,
labelColor: Color(0xff1967d2),
unselectedLabelColor: Color(0xff5f6368),
isScrollable: true,
indicator: MD2Indicator(
indicatorSize: MD2IndicatorSize.full,
indicatorHeight: 8.0,
indicatorColor: Colors.green,
),
tabs: <Widget>[
Tab(
text: "Home",
),
Tab(
text: "Personal info",
),
Tab(
text: "Data & personalization",
),
Tab(
text: "Security",
)
],
),
),
)
,
),
);
}
}
enum MD2IndicatorSize {
tiny,
normal,
full,
}
class MD2Indicator extends Decoration {
final double indicatorHeight;
final Color indicatorColor;
final MD2IndicatorSize indicatorSize;
const MD2Indicator(
{@required this.indicatorHeight,
@required this.indicatorColor,
@required this.indicatorSize});
@override
_MD2Painter createBoxPainter([VoidCallback onChanged]) {
return new _MD2Painter(this, onChanged);
}
}
class _MD2Painter extends BoxPainter {
final MD2Indicator decoration;
_MD2Painter(this.decoration, VoidCallback onChanged)
: assert(decoration != null),
super(onChanged);
@override
void paint(Canvas canvas, Offset offset, ImageConfiguration configuration) {
assert(configuration != null);
assert(configuration.size != null);
Rect rect;
if (decoration.indicatorSize == MD2IndicatorSize.full) {
rect = Offset(offset.dx,
(configuration.size.height - decoration.indicatorHeight ?? 3)) &
Size(configuration.size.width, decoration.indicatorHeight ?? 3);
} else if (decoration.indicatorSize == MD2IndicatorSize.normal) {
rect = Offset(offset.dx + 6,
(configuration.size.height - decoration.indicatorHeight ?? 3)) &
Size(configuration.size.width - 12, decoration.indicatorHeight ?? 3);
} else if (decoration.indicatorSize == MD2IndicatorSize.tiny) {
rect = Offset(offset.dx + configuration.size.width / 2 - 8,
(configuration.size.height - decoration.indicatorHeight ?? 3)) &
Size(16, decoration.indicatorHeight ?? 3);
}
final Paint paint = Paint();
paint.color = decoration.indicatorColor ?? Color(0xff1967d2);
paint.style = PaintingStyle.fill;
canvas.drawRRect(
RRect.fromRectAndCorners(rect,
topRight: Radius.circular(8), topLeft: Radius.circular(8)),
paint);
}
}
以上摘录自此软件包
https://pub.dev/packages/md2_tab_indicator
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