第11章组件装饰和视觉效果-CustomPainter自定义画板-绘制直线
防采集标记:亢少军老师的课程和资料
import 'package:flutter/material.dart';
import 'dart:math';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'CustomPaint绘制直线示例',
home: Scaffold(
appBar: AppBar(
title: Text(
'CustomPaint绘制直线示例',
style: TextStyle(color: Colors.white),
),
),
body: Center(
child: SizedBox(
width: 500.0,
height: 500.0,
child: CustomPaint(
painter: LinePainter(),
child: Center(
child: Text(
'绘制直线',
style: const TextStyle(
fontSize: 38.0,
fontWeight: FontWeight.w600,
color: Colors.black,
),
),
),
),
)
),
),
);
}
}
//继承于CustomPainter并且实现CustomPainter里面的paint和shouldRepaint方法
class LinePainter extends CustomPainter {
//定义画笔
Paint _paint = new Paint()
..color = Colors.black
..strokeCap = StrokeCap.square
..isAntiAlias = true
..strokeWidth = 3.0
..style = PaintingStyle.stroke;
///重写绘制内容方法
@override
void paint(Canvas canvas, Size size) {
//绘制直线
canvas.drawLine(Offset(20.0, 20.0), Offset(300.0, 20.0), _paint);
}
///重写是否需要重绘的
@override
bool shouldRepaint(CustomPainter oldDelegate) {
return false;
}
}
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@作者: 亢少军