Flutter自定义Decoration实现特殊的背景框

我们常用的BoxDecoration可以实现这些功能

const BoxDecoration({
this.color, // 底色
this.image, // 图片
this.border, 边色
this.borderRadius, // 圆角度
this.boxShadow, // 阴影
this.gradient, // 渐变
this.backgroundBlendMode, // 混合Mode
this.shape = BoxShape.rectangle, // 形状
})

有些特殊的背景需要，比如：

要实现上面的背景框，可以通过自定义decoration，通过canvas和painter实现，代码如下：

import 'package:flutter/material.dart';class CustomDecoration extends Decoration {final double marginLeft;//顶角离左边的距离final Color lineColor;final double height;//顶角高度final double radius;//边框圆角大小CustomDecoration({required this.marginLeft,this.radius = 8,this.lineColor = Colors.black,this.height = 16});@overrideBoxPainter createBoxPainter([VoidCallback? onChanged]) {// TODO: implement createBoxPainterreturn _CustomPainter(this, marginLeft, lineColor, radius, height);}
}class _CustomPainter extends BoxPainter {final CustomDecoration customDecoration;Paint? painter;final double marginLeft;final Color lineColor;final double height;final double radius;_CustomPainter(this.customDecoration, this.marginLeft, this.lineColor,this.radius, this.height): painter = Paint()..color = lineColor..strokeWidth = 1..style = PaintingStyle.stroke;@overridevoid paint(Canvas canvas, Offset offset, ImageConfiguration configuration) {var size = configuration.size;Offset leftTop = offset;Offset rightTop = leftTop.translate(size!.width, 0);Offset leftBottom = leftTop.translate(0, size.height);Offset rightBottom = leftTop.translate(size.width, size.height);final leftStart = leftTop.translate(radius, 0); //点1final leftPoint = leftTop.translate(marginLeft, 0); //点2final topPoint = leftPoint.translate(height, -height); // 点3final rightPoint = leftPoint.translate(height*2, 0); // 点4final top5 = rightTop.translate(-radius, 0);final top6 = rightTop.translate(0, radius);final bottom7 = rightBottom.translate(0, -radius);final bottom8 = rightBottom.translate(-radius, 0);final bottom9 = leftBottom.translate(radius, 0);final bottom10 = leftBottom.translate(0, -radius);final top11 = leftTop.translate(0, radius);final path = Path()..moveTo(leftStart.dx, leftStart.dy)..lineTo(leftPoint.dx, leftPoint.dy)..lineTo(topPoint.dx, topPoint.dy)..lineTo(rightPoint.dx, rightPoint.dy)..lineTo(top5.dx, top5.dy)..arcToPoint(top6, radius: Radius.circular(radius))..lineTo(bottom7.dx, bottom7.dy)..arcToPoint(bottom8, radius: Radius.circular(radius))..lineTo(bottom9.dx, bottom9.dy)..arcToPoint(bottom10, radius: Radius.circular(radius))..lineTo(top11.dx, top11.dy)..arcToPoint(leftStart, radius: Radius.circular(radius));canvas.drawPath(path, painter!..style = PaintingStyle.stroke);}
}

OK，以上demo主要通过canvas的drawPath方法直接路径绘制出来，也可以按照这个思路绘制其他复杂的边框。此实例仅供参考！

Flutter自定义Decoration实现特殊的背景框相关推荐

Flutter 自定义Decoration
Flutter 中可以给Container设置decoration来设置背景,边框等等效果,非常方便. Container(decoration: TestDecoration(),); 但是Flu ...
Flutter 自定义组件实战之Cupertino（iOS）风格的复选框
继上一篇Flutter自定义组件的视频短课(视频地址: https://www.bilibili.com/video/BV1ap4y1U7UB/ )后,我们继续来聊自定义组件.视频中我为大家详解了Cu ...
Flutter 画笔绘制二维码扫描框
文章目录一.CustomPaint介绍 1. CustomPaint 2. CustomPainter 3. Paint & Canvas 4. 示例(绘制文本背景) 二.计算扫描框四个点坐 ...
flutter 自定义日历
在项目中需要实现一个日历展示我发布过的动态,效果如图,同时需要左右滑动翻页尝试使用组件发现可自定义的范围比较小,且无法实现需求,看到这篇Flutter自定义日历,实现日期底部不同颜色的日历事件_ap ...
Flutter之Decoration
1.不废话,先爆照看效果 2.Decoration介绍 Flutter的Decoration可以设置:背景色背景图边框圆角阴影渐变色的等属性,有点像android里面的shape,Deco ...
android TextView下划线，圆角边框，数逐字显示，虚线边框，渐变色背景框，阴影背景框
长方形 <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="h ...
Flutter 自定义Widget——风车实现
最近在做一个天气模块的时候,风力需要显示一个旋转的风车,实现效果如下: 需求分析我们可以把上面的效果拆分为两个部分实现: 1.画一个风车的FanWidget 2.旋转动画一.风车Widget实现 ...
自定义 FlowLayout流式布局搜索框加 GreenDao存取搜索记录，使用RecyclerView展示
输入框布局的shape <?xml version="1.0" encoding="utf-8"?> <shape xmlns:android ...
flutter自定义单元格_使用自定义大小的单元格制作复杂的UICollectionView布局（第1部分）
flutter自定义单元格 Recently I built a screen with a pretty complex layout containing self sizing cells. I ...

Flutter自定义Decoration实现特殊的背景框

Flutter自定义Decoration实现特殊的背景框相关推荐

最新文章

热门文章