同一颜色的圆
例子样式:
废话不多说 直接上代码,注释清楚!
1.调用该方法 如果只要一个圆，赋值completeColor, completeWidth, completePercent就可以，剩下的不用赋值 就是一个圆
2.如果需要俩圆的话直接调用赋值就行
3.如果只需要一个虚线圆的话，赋值isDividerRound = true; ,lineColor, width, 剩下的不用写,completeWidth 不得大于0
这是一个全圆就是比例是百分之百的圆,可以自行修改
/*
* 如果只有一个圆的情况下,请设置已完成的圆 默认的圆的颜色不要设置
*/
import 'dart:math';
import 'package:flutter/cupertino.dart';
class MyPainter extends CustomPainter {
//默认的线的背景颜色
Color? lineColor;
//默认的线的宽度
double width;
//已完成线的颜色
Color completeColor;
//已完成的百分比
double completePercent;
//已完成的线的宽度
double completeWidth;
// 从哪开始 1从下开始, 2 从上开始 3 从左开始 4 从右开始 默认从下开始
double startType;
//是不是虚线的圈
bool isDividerRound;
//中间的实圆 统计线条是不是渐变的圆
bool isGradient;
//结束的位置
double endAngle;
//默认的线的背景颜色
List<Color> lineColors;
//实心圆阴影颜色
// Color shadowColor;
//渐变圆 深色在下面 还是在左面 默认在下面
bool isTransform;
MyPainter({
required this.lineColor,
required this.completeColor,
required this.completePercent,
required this.width,
required this.completeWidth,
this.startType = 1,
this.isDividerRound = false,
this.isGradient = false,
this.endAngle = pi * 2,
required this.lineColors,
this.isTransform = false,
// this.shadowColor,
});
@override
void paint(Canvas canvas, Size size) {
Offset center = Offset(size.width / 2, size.height / 2); // 坐标中心
double radius = min(size.width / 2, size.height / 2); // 半径
//是否有第二层圆
if (lineColor != null) {
//是不是 虚线圆
if (isDividerRound) {
//背景的线
Paint line = Paint()
..color = lineColor!
// ..strokeCap = StrokeCap.round
..style = PaintingStyle.stroke
..isAntiAlias = true //抗锯齿
..strokeWidth = width;
double i = 0.00;
while (i < pi * 2) {
canvas.drawArc(Rect.fromCircle(center: center, radius: radius), i,
0.04, false, line);
i = i + 0.08;
}
} else {
//背景的线 实线
Paint line = Paint()
..color = lineColor!
..strokeCap = StrokeCap.round
..style = PaintingStyle.stroke
..strokeWidth = width;
canvas.drawCircle(
// 画圆方法
center,
radius,
line);
}
}
//画上面的圆
if (completeWidth > 0) {
double arcAngle = 2 * pi * (completePercent / 100);
// 从哪开始 1从下开始, 2 从上开始 3 从左开始 4 从右开始 默认从下开始
double start = pi / 2;
if (startType == 2) {
start = -pi / 2;
} else if (startType == 3) {
start = pi;
} else if (startType == 4) {
start = pi * 2;
}
//创建画笔
Paint paint = Paint()
..strokeCap = StrokeCap.round
..style = PaintingStyle.stroke
..strokeWidth = completeWidth;
///是渐变圆
if (isGradient == true) {
//渐变圆 深色位置偏移量 默认深色在下面
double transform;
if (isTransform == false) {
//深色在下面
transform = -pi / 2;
} else {
//深色在左面
transform = pi * 2;
}
paint.shader = SweepGradient(
startAngle: 0.0,
endAngle: pi * 2,
colors: lineColors,
tileMode: TileMode.clamp,
transform: GradientRotation(transform),
).createShader(
Rect.fromCircle(center: center, radius: radius),
);
canvas.drawArc(Rect.fromCircle(center: center, radius: radius), start,
arcAngle, false, paint);
} else {
///是实体圆
paint.color = completeColor;
canvas.drawArc(
Rect.fromCircle(center: center, radius: radius),
start, // -pi / 2,从正上方开始 pi / 2,从下方开始
arcAngle,
false,
paint,
);
}
}
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => false;
}
实践示例
我们用 Flutter 新建项目的例子代码来演示，如下：
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
CustomPaint(
size: const Size(200, 200),
foregroundPainter: MyPainter(
lineColor: const Color(0xFF000000),
lineColors: [const Color(0xFF000000), const Color(0xFFFFFFFF)],
completeWidth: 10,
width: 6,
completePercent: 90,
completeColor: const Color(0xFFFF000F),
),
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
渐变色的圆
代码看看就会了
import 'dart:math';
import 'package:flutter/cupertino.dart';
///渐变圆
class MyGradientPainter extends CustomPainter {
//默认的线的背景颜色
List<Color> lineColor;
//默认的线的宽度
double width;
double endAngle;
MyGradientPainter({
required this.lineColor,
required this.width,
this.endAngle = pi * 2,
});
@override
void paint(Canvas canvas, Size size) {
Offset center = Offset(size.width / 2, size.height / 2); // 坐标中心
double radius = min(size.width / 2, size.height / 2); // 半径
var paint = Paint()
..strokeCap = StrokeCap.round
..style = PaintingStyle.stroke
..isAntiAlias = true //抗锯齿
..strokeWidth = width;
paint.shader = SweepGradient(
startAngle: 0.0,
endAngle: pi * 2,
colors: lineColor,
transform: const GradientRotation(pi * 1.2),
).createShader(
Rect.fromCircle(center: center, radius: radius),
);
canvas.drawArc(Rect.fromCircle(center: center, radius: radius), 0, 2 * pi,
false, paint);
}
@override
bool shouldRepaint(CustomPainter oldDelegate) => false;
}
实践示例
我们用 Flutter 新建项目的例子代码来演示，如下：
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
@override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
const Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.headline4,
),
CustomPaint(
size: const Size(200, 200),
foregroundPainter: MyGradientPainter(
width: 8, lineColor: [const Color(0xFF000000),const Color(0xFFFFFFFF)]),
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: const Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}