user-interface - 如何在 flutter 中有这样的圆形？

Question

我正在尝试在我的 flutter 项目中创建这样的圆形。我尝试在容器中使用 border-radius 。但它并没有像我预期的那样工作。

那么，我怎样才能得到像给定图片这样的形状呢？

我试过使用这样的容器。

    Container(
            height: 72,
            width: 211,
            decoration: BoxDecoration(
              color: Colors.blue,
              borderRadius: BorderRadius.only(
                topRight: Radius.circular(50),
                topLeft: Radius.circular(30))
            ),
          )

Answer 1

您几乎可以使用 CustomPaint 绘制任何东西，看看:

https://api.flutter.dev/flutter/rendering/CustomPainter-class.html

在下面的代码中，我画了类似那个圆圈的东西:

import "package:flutter/material.dart";

void main() {
  runApp(MaterialApp(title: "", home: Home()));
}

class Home extends StatefulWidget {
  @override
  _HomeState createState() => _HomeState();
}

class _HomeState extends State<Home> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(),
        body: Container(
            width: double.infinity,
            height: double.infinity,
            child: CustomPaint(
              painter: CirclePainter(),
            )),
      ),
    );
  }
}

class CirclePainter extends CustomPainter {
  final Paint lightBluePaint = Paint()..color = Color(0xFFbde5fa);
  final Paint bluePaint = Paint()..color = Color(0xFF5abef2);
  final TextPainter textPainter = TextPainter(
    textDirection: TextDirection.ltr,
  );

  final TextStyle textStyle = TextStyle(
      color: Colors.white.withAlpha(240),
      fontSize: 18,
      letterSpacing: 1.2,
      fontWeight: FontWeight.w900);

  @override
  void paint(Canvas canvas, Size size) {
    var rect = Rect.fromLTRB(
        -100, size.height - 120, size.width * 0.7, size.height + 250);

    final Path circle = Path()..addOval(rect);
    final Path smallCircle = Path()..addOval(rect.inflate(50));

    canvas.drawPath(smallCircle, lightBluePaint);
    canvas.drawPath(circle, bluePaint);

    drawText(canvas, size, 'Write now');
  }

  void drawText(Canvas canvas, Size size, String text) {
    textPainter.text = TextSpan(style: textStyle, text: text);
    textPainter.layout();
    textPainter.paint(canvas, Offset(50, size.height - 60));
  }

  @override
  bool shouldRepaint(CustomPainter oldDelegate) {
    return true;
  }
}