今天就跟大家聊聊有关Flutter中怎么利用Clipper自定义形状，可能很多人都不太了解，为了让大家更加了解，小编给大家总结了以下内容，希望大家根据这篇文章可以有所收获。
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ClipOval 圆形裁剪
ClipOval( child: SizedBox( width: 120.0, height: 120.0, child: Image.asset( Config.assets_avatar_1, ), ),);
CircleAvatar 圆形头像
CircleAvatar( radius: 60.0, backgroundImage: AssetImage( Config.assets_avatar_1, ),);
Container Decoration 装饰形状
通过BoxShape.circle实现圆形图片
Container( width: 120.0, height: 120.0, decoration: BoxDecoration( shape: BoxShape.circle, image: DecorationImage( image: AssetImage( Config.assets_avatar_1, ), ), ))；
通过BorderRadius实现圆形图片
Container( width: 120.0, height: 120.0, decoration: BoxDecoration( borderRadius: BorderRadius.all(Radius.circular(60.0)), image: DecorationImage( image: AssetImage( Config.assets_avatar_1, ), ), ),)
ClipPath 路径剪裁
ClipPath( clipper: TriangleClipper(ClipperPosition.LeftTop), child: Container( width: 16.0, height: 16.0, decoration: BoxDecoration( color: Colors.blue, ), ),);enum ClipperPosition { LeftTop, RightTop,}class TriangleClipper extends CustomClipper { final ClipperPosition position; TriangleClipper(this.position); @override Path getClip(Size size) { final path = Path(); path.lineTo(0.0, 0.0); if (position == ClipperPosition.LeftTop) { path.lineTo(size.width, 0.0); path.lineTo(size.width, size.height); } else if (position == ClipperPosition.RightTop) { path.lineTo(size.width, 0.0); path.lineTo(0.0, size.height); } path.close(); return path; } @override bool shouldReclip(CustomClipper oldClipper) { return false; }}
ClipRect 矩形剪裁
Container( alignment: Alignment.topCenter, color: Colors.transparent, child: Container( color: Colors.green, child: ClipRect( clipper: _RectClipper(20.0), child: Image.asset( Config.assets_avatar_1, width: 160.0, height: 160.0, fit: BoxFit.fill, ), ), ),);class _RectClipper extends CustomClipper { /// Remove side of size final double removeSize; _RectClipper(this.removeSize); @override Rect getClip(Size size) { return new Rect.fromLTRB( removeSize, removeSize, size.width - removeSize, size.height - removeSize, ); } @override bool shouldReclip(CustomClipper oldClipper) { return false; }}
ClipRRect 圆角矩形剪裁
ClipRRect( borderRadius: BorderRadius.all(Radius.circular(16.0)), child: Image.asset( Config.assets_avatar_1, fit: BoxFit.fill, width: 120.0, height: 120.0, ),);
Star Rating(CustomPaint) 评分控件
评分控件 UI图
实现方案
使用CustomPaint结合ClipPath画出单个五角星；
使用Stack渲染两层画面 背景层，一排灰色五角星 前景层，一排亮色五角星，并使用ClipRect截取一定Width
实现代码
class StarRatingDemo extends StatefulWidget { @override _StarRatingDemoState createState() => _StarRatingDemoState();}class _StarRatingDemoState extends State { /// ClipPath Star Rating _buildClipPathStarRating(double rate, int count) { return Container( padding: EdgeInsets.fromLTRB(24.0, 16.0, 24.0, 0.0), child: StaticRatingBar( size: 50.0, rate: rate, count: count, ), ); } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( centerTitle: true, title: Text('Star Rating'), ), body: ListView( physics: BouncingScrollPhysics(), children: [ // _buildClipPathStarRating(1.0, 1), _buildClipPathStarRating(0.5, 5), _buildClipPathStarRating(2.0, 5), _buildClipPathStarRating(3.0, 5), _buildClipPathStarRating(4.0, 5), _buildClipPathStarRating(5.0, 5), _buildClipPathStarRating(5.5, 6), SizedBox(height: 16.0), ], ), ); }}class StaticRatingBar extends StatelessWidget { /// Number of stars final int count; /// Init rate final double rate; /// Size of the starts final double size; final Color colorLight; final Color colorDark; StaticRatingBar({ this.rate = 5, this.colorLight = const Color(0xFF1E88E5), this.colorDark = const Color(0xFFEEEEEE), this.count = 5, this.size = 60, }); Widget buildDarkStar() { return SizedBox( width: size * count, height: size, child: CustomPaint( painter: _PainterStars( count: count, color: colorDark, strokeWidth: 0.0, size: this.size / 2, style: PaintingStyle.fill, ), ), ); } Widget buildLightStar() { return ClipRect( clipper: _RatingBarClipper(rate * size), child: SizedBox( height: size, width: size * count, child: CustomPaint( painter: _PainterStars( count: count, strokeWidth: 0.0, color: colorLight, size: this.size / 2, style: PaintingStyle.fill, ), ), ), ); } @override Widget build(BuildContext context) { return Stack( children: [ buildDarkStar(), buildLightStar(), ], ); }}class _RatingBarClipper extends CustomClipper { final double width; _RatingBarClipper(this.width); @override Rect getClip(Size size) { return Rect.fromLTRB(0.0, 0.0, width, size.height); } @override bool shouldReclip(_RatingBarClipper oldClipper) { return false; }}class _PainterStars extends CustomPainter { final double size; final int count; final Color color; final PaintingStyle style; final double strokeWidth; _PainterStars({ this.size, this.count, this.color, this.strokeWidth, this.style, }); double degree2Radian(int degree) { return (pi * degree / 180); } Path createStarPath(double radius, Path path) { double radian = degree2Radian(36); double radiusIn = (radius * sin(radian / 2) / cos(radian)) * 1.1; path.moveTo((radius * cos(radian / 2)), 0.0); path.lineTo( (radius * cos(radian / 2) + radiusIn * sin(radian)), (radius - radius * sin(radian / 2)), ); path.lineTo( (radius * cos(radian / 2) * 2), (radius - radius * sin(radian / 2)), ); path.lineTo( (radius * cos(radian / 2) + radiusIn * cos(radian / 2)), (radius + radiusIn * sin(radian / 2)), ); path.lineTo( (radius * cos(radian / 2) + radius * sin(radian)), (radius + radius * cos(radian)), ); path.lineTo((radius * cos(radian / 2)), (radius + radiusIn)); path.lineTo( (radius * cos(radian / 2) - radius * sin(radian)), (radius + radius * cos(radian)), ); path.lineTo( (radius * cos(radian / 2) - radiusIn * cos(radian / 2)), (radius + radiusIn * sin(radian / 2)), ); path.lineTo(0.0, (radius - radius * sin(radian / 2))); path.lineTo( (radius * cos(radian / 2) - radiusIn * sin(radian)), (radius - radius * sin(radian / 2)), ); path.lineTo((radius * cos(radian / 2)), 0.0); return path; } @override void paint(Canvas canvas, Size size) { Paint paint = Paint(); paint.strokeWidth = strokeWidth; paint.color = color; paint.style = style; Path path = Path(); double offset = strokeWidth > 0 ? strokeWidth + 2 : 0.0; path = createStarPath(this.size - offset, path); for (int i = 0; i < count - 1; i++) { path = path.shift(Offset(this.size * 2, 0.0)); path = createStarPath(this.size - offset, path); } if (offset > 0) { path = path.shift(Offset(offset, offset)); } path.close(); canvas.drawPath(path, paint); } @override bool shouldRepaint(_PainterStars oldDelegate) { return oldDelegate.size != this.size; }}
看完上述内容，你们对Flutter中怎么利用Clipper自定义形状有进一步的了解吗？如果还想了解更多知识或者相关内容，请关注创新互联行业资讯频道，感谢大家的支持。
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