颤动：画半圈

Question

如何画这样的半圈？拜托，我不想要一个Container小部件并改变它的半径

Answer 1

我不明白你的意思是“我不想要一个容器小部件并改变它的半径”，但这是我创建一个半圆的方法：

class Test extends StatelessWidget {
      @override
      Widget build(BuildContext context) {
        return new Scaffold(
          body: new Container(
            padding: EdgeInsets.all(64.0),
            child: new Column(
              children: <Widget>[
                new ClipPath(
                  clipper: new CustomHalfCircleClipper(),
                  child: new Container(
                    height: 300.0,
                    width: 300.0,
                    decoration: new BoxDecoration(color: Colors.blue, borderRadius: BorderRadius.circular(150.0) ),
                  ),
                )
              ],
            ),
          ),
        );
      }
    }

    class CustomHalfCircleClipper extends CustomClipper<Path> {
      @override
      Path getClip(Size size) {
        final Path path = new Path();
        path.lineTo(0.0, size.height / 2);
        path.lineTo(size.width, size.height / 2);
        path.lineTo(size.width, 0);
        return path;
      }
      @override
      bool shouldReclip(CustomClipper<Path> oldClipper) {
        return true;
      }
    }