1 继续关系:

BoxDecoration:实现边框、圆角、阴影、形状、渐变、背景图像

ShapeDecoration:实现四个边分别指定颜色和宽度、底部线、矩形边色、圆形边色、体育场(竖向椭圆)、 角形(八边角)边色

FlutterLogoDecoration:实现Flutter图片

UnderlineTabindicator:下划线

2 介绍

一个背景装饰对象,相当于Android中的shape.xml,定制各种各样的背景(边框、圆角、阴影、形状、渐变、背景图像)。

3 BoxDecoration例子: 构造方法:

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
})

  • 3.1 边框+圆角:

decoration: new BoxDecoration(
border: new Border.all(color: Color(0xFFFF0000), width: 0.5), // 边色与边宽度
color: Color(0xFF9E9E9E), // 底色
// borderRadius: new BorderRadius.circular((20.0)), // 圆角度
borderRadius: new BorderRadius.vertical(top: Radius.elliptical(20, 50)), // 也可控件一边圆角大小
),

  • 3.2 阴影:

decoration: new BoxDecoration(
border: new Border.all(color: Color(0xFFFF0000), width: 0.5), // 边色与边宽度
// 生成俩层阴影,一层绿,一层黄, 阴影位置由offset决定,阴影模糊层度由blurRadius大小决定(大就更透明更扩散),阴影模糊大小由spreadRadius决定
boxShadow: [BoxShadow(color: Color(0x99FFFF00), offset: Offset(5.0, 5.0), blurRadius: 10.0, spreadRadius: 2.0), BoxShadow(color: Color(0x9900FF00), offset: Offset(1.0, 1.0)), BoxShadow(color: Color(0xFF0000FF))],
),

  • 3.3 形状(圆形与矩形)


decoration: new BoxDecoration(
border: new Border.all(color: Color(0xFFFFFF00), width: 0.5), // 边色与边宽度
color: Color(0xFF9E9E9E), // 底色
// shape: BoxShape.circle, // 圆形,使用圆形时不可以使用borderRadius
shape: BoxShape.rectangle, // 默认值也是矩形
borderRadius: new BorderRadius.circular((20.0)), // 圆角度
),

  • 3.4 渐变(环形、扫描式、线性):

decoration: new BoxDecoration(
border: new Border.all(color: Color(0xFFFFFF00), width: 0.5), // 边色与边宽度
// 环形渲染
gradient: RadialGradient(colors: [Color(0xFFFFFF00), Color(0xFF00FF00), Color(0xFF00FFFF)],radius: 1, tileMode: TileMode.mirror)
//扫描式渐变
// gradient: SweepGradient(colors: [Color(0xFFFFFF00), Color(0xFF00FF00), Color(0xFF00FFFF)], startAngle: 0.0, endAngle: 1*3.14)
// 线性渐变
// gradient: LinearGradient(colors: [Color(0xFFFFFF00), Color(0xFF00FF00), Color(0xFF00FFFF)], begin: FractionalOffset(1, 0), end: FractionalOffset(0, 1))
),

  • 3.5 背景图像:

decoration: new BoxDecoration(
border: new Border.all(color: Color(0xFFFFFF00), width: 0.5), // 边色与边宽度
image: new DecorationImage(
image: new NetworkImage('https://avatar.csdn.net/8/9/A/3_chenlove1.jpg'), // 网络图片
// image: new AssetImage('graphics/background.png'), 本地图片
fit: BoxFit.fill // 填满
// centerSlice: new Rect.fromLTRB(270.0, 180.0, 1360.0, 730.0),// 固定大小
),
),

4 ShapeDecoration例子: 构造方法:

const ShapeDecoration({
this.color,
this.image,
this.gradient,
this.shadows,
@required this.shape,
})
除了shape,其他与BoxDecoration一致,shape研究:

decoration: new ShapeDecoration(
color: Color(0xFFFF00FF), // 底色
// 统一四边颜色和宽度
shape: Border.all(color: Color(0xFF00FFFF),style: BorderStyle.solid,width: 2)
// 四个边分别指定颜色和宽度, 当只给bottom时与UnderlineInputBorder一致效果
// shape: Border(top: b, bottom: b, right: b, left: b)
// 底部线
// shape: UnderlineInputBorder( borderSide:BorderSide(color: Color(0xFFFFFFFF), style: BorderStyle.solid, width: 2))
// 矩形边色
// shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(10)), side: BorderSide(color: Color(0xFFFFFFFF), style: BorderStyle.solid, width: 2))
// 圆形边色
// shape: CircleBorder(side: BorderSide(color: Color(0xFFFFFF00), style: BorderStyle.solid, width: 2))
// 体育场(竖向椭圆)
// shape: StadiumBorder(side: BorderSide(width: 2, style: BorderStyle.solid, color: Color(0xFF00FFFF))
// 角形(八边角)边色
// shape: BeveledRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(10)), side: BorderSide(color: Color(0xFFFFFFFF), style: BorderStyle.solid, width: 2))
),

5 FlutterLogoDecoration例子: 构造方法:

const FlutterLogoDecoration({
this.lightColor = const Color(0xFF42A5F5), // Colors.blue[400]
this.darkColor = const Color(0xFF0D47A1), // Colors.blue[900]
this.textColor = const Color(0xFF616161),
this.style = FlutterLogoStyle.markOnly,
this.margin = EdgeInsets.zero,
})
这个就不解析了,Flutter的logo,开发没啥用!

6 UnderlineTabindicator例子: 构造方法:

const UnderlineTabIndicator({
this.borderSide = const BorderSide(width: 2.0, color: Colors.white),
this.insets = EdgeInsets.zero,
})
这个比较简单就是加下划线,可以设置Insets值(控制下划高底,左右边距)

decoration: new UnderlineTabIndicator(
borderSide: BorderSide(width: 2.0, color: Colors.white),
insets: EdgeInsets.fromLTRB(0,0,0,10)

Last modification:August 18th, 2020 at 10:19 am
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