flutter自定义视图

CustomPaint

CustomPaint(
            // painter: MyPainter(),
            foregroundPainter: MyPainter(),
            child: Text('hello customPaint'),
          )

class MyPainter extends CustomPainter {
  @override
  void paint(Canvas canvas, Size size) {
    Paint paint = Paint()
    ..isAntiAlias = true
    ..style = PaintingStyle.stroke
    ..strokeWidth = 5
    ..color = Colors.green;
    canvas.drawRect(Offset.zero & Size(100, 100), paint);
    canvas.drawArc(Offset(10, 10) & Size(40, 40), 3, 3, true, paint);
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    // TODO: implement shouldRepaint
    return false;
  }
}

RenderBox

建议使用CustomPaint，CustomPaint内部其实就是对RenderBox做了封装

class CircleView extends SingleChildRenderObjectWidget{
  @override
  RenderObject createRenderObject(BuildContext context) {
    return RenderCircle();
  }
}

class RenderCircle extends RenderBox{
  Paint _paint;
  Path _path;
  
  RenderCircle(){
    _paint = Paint();
    _paint.isAntiAlias = true;
    _paint.style = PaintingStyle.fill;
    _path = Path();
  }

  @override
  void performLayout() {

  }

  @override
  void paint(PaintingContext context, Offset offset) {
    var canvas = context.canvas;
    //通过canvas绘制
  }
}