Flutter实现矩形取色器的封装

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我是靠谱客的博主细心冬日，这篇文章主要介绍Flutter实现矩形取色器的封装，现在分享给大家，希望可以做个参考。

前言

最近看插件库上少有的取色器大都是圆形的或者奇奇怪的的亚子，所以今天做两个矩形的颜色取色器

提示：以下是本篇文章正文内容，下面案例可供参考

一、BarTypeColorPicker

条形选色板的功能实现，颜色的获取是通过位置来判断，然后赋予相应的颜色。这个封装好的组件可通过colorListener、onTapUpListener的回调方法，把颜色传出去。

代码如下（示例）：

复制代码

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

///描述：条形选色板

class BarTypeColorPicker extends StatefulWidget {
  final Color initialColor;
  final ValueChanged<Color> colorListener;
  final ValueChanged<Color> onTapUpListener;
  final int colorWidth;
  final int colorHeight;
  final Color color;

const BarTypeColorPicker(
      {Key key,
      this.initialColor,
      this.colorListener,
      this.onTapUpListener,
      this.colorWidth,
      this.colorHeight,
      this.color})
      : super(key: key);

@override
  _BarTypeColorPickerState createState() => _BarTypeColorPickerState(
        colorWidth.toDouble(),
        colorHeight.toDouble(),
      );
}

class _BarTypeColorPickerState extends State<BarTypeColorPicker> {
  double _top = 0.0;
  double _left = 0.0;
  double _Thumbsize = 20;
  double lightness;
  double _colorwidth;
  double _colorHeight;
  Color _color;

_BarTypeColorPickerState(double colorwidth, double colorHeight) {
    this._colorwidth = colorwidth;
    this._colorHeight = colorHeight;
  }

@override
  void initState() {
    super.initState();
  }

@override
  Widget build(BuildContext context) {
    return Center(
      child: GestureDetector(
        onPanStart: (DragStartDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanDown: (DragDownDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanUpdate: (DragUpdateDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanEnd: (DragEndDetails detail) {
          if (widget.onTapUpListener != null) {
            widget.onTapUpListener(_color);
          }
        },
        onTapUp: (TapUpDetails detail) {
          if (widget.onTapUpListener != null) {
            widget.onTapUpListener(_color);
          }
        },
        child: ColorRect(
            colorHeight: _colorHeight,
            colorwidth: _colorwidth,
            top: _top,
            Thumbsize: _Thumbsize,
            left: _left,
            color: _color),
      ),
    );
  }

class ColorRect extends StatelessWidget {
  ColorRect({
    Key key,
    @required double colorHeight,
    @required double colorwidth,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _colorHeight = colorHeight,
        _colorwidth = colorwidth,
        _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

final double _colorHeight;
  final double _colorwidth;
  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;
  List<Color> colorList = [
    Color(0xFFFF0000),
    Color(0xFFFFFF00),
    Color(0xFF00FF00),
    Color(0xFF00FFFF),
    Color(0xFF0000FF),
    Color(0xFFFF00FF),
    Color(0xFFFFFFFF),
  ];

@override
  Widget build(BuildContext context) {
    return Container(
      width: _colorwidth,
      height: _colorHeight,
      child: Stack(
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: colorList
                .map(
                  (e) => Container(
                    padding: EdgeInsets.symmetric(horizontal: 2),
                    height: _colorHeight,
                    width: _colorwidth / 7,
                    child: Container(
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(10),
                        color: e,
                      ),
                    ),
                  ),
                )
                .toList(),
          ),
          Container(
              child: Thumb(
                  top: _top,
                  Thumbsize: _Thumbsize,
                  left: _left,
                  color: _color)),
        ],
      ),
    );
  }
}

class Thumb extends StatelessWidget {
  const Thumb({
    Key key,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

@override
  Widget build(BuildContext context) {
    return Positioned(
        top: _top - _Thumbsize / 2,
        left: _left - _Thumbsize / 2,
        child: GestureDetector(
            child: Container(
          child: Icon(
            Icons.circle,
            color: _color,
            size: _Thumbsize,
          ),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10),
            boxShadow: [
              BoxShadow(
                blurRadius: 0.1, //阴影范围
                spreadRadius: 0.001, //阴影浓度
                color: Colors.black, //阴影颜色
              ),
            ],
          ),
        )));
  }
}

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import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';


///描述：条形选色板

class BarTypeColorPicker extends StatefulWidget {
  final Color initialColor;
  final ValueChanged<Color> colorListener;
  final ValueChanged<Color> onTapUpListener;
  final int colorWidth;
  final int colorHeight;
  final Color color;

  const BarTypeColorPicker(
      {Key key,
      this.initialColor,
      this.colorListener,
      this.onTapUpListener,
      this.colorWidth,
      this.colorHeight,
      this.color})
      : super(key: key);

  @override
  _BarTypeColorPickerState createState() => _BarTypeColorPickerState(
        colorWidth.toDouble(),
        colorHeight.toDouble(),
      );
}

class _BarTypeColorPickerState extends State<BarTypeColorPicker> {
  double _top = 0.0;
  double _left = 0.0;
  double _Thumbsize = 20;
  double lightness;
  double _colorwidth;
  double _colorHeight;
  Color _color;

  _BarTypeColorPickerState(double colorwidth, double colorHeight) {
    this._colorwidth = colorwidth;
    this._colorHeight = colorHeight;
  }

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: GestureDetector(
        onPanStart: (DragStartDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanDown: (DragDownDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanUpdate: (DragUpdateDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if (widget.colorListener != null) {
            widget.colorListener(_color);
          }
        },
        onPanEnd: (DragEndDetails detail) {
          if (widget.onTapUpListener != null) {
            widget.onTapUpListener(_color);
          }
        },
        onTapUp: (TapUpDetails detail) {
          if (widget.onTapUpListener != null) {
            widget.onTapUpListener(_color);
          }
        },
        child: ColorRect(
            colorHeight: _colorHeight,
            colorwidth: _colorwidth,
            top: _top,
            Thumbsize: _Thumbsize,
            left: _left,
            color: _color),
      ),
    );
  }

  void buildSetState(Offset localPosition, BuildContext context) {
    return setState(() {
      _left = localPosition.dx;
      _top = localPosition.dy;
      if (_left < 0) {
        _left = 0;
      } else if (0 <= _left && _left <= _colorwidth) {
        _left = _left;
      } else if (_left > _colorwidth) {
        _left = (_colorwidth);
      }
      if ((_colorwidth / 7) * 0 < _left && _left < (_colorwidth / 7) * 1) {
        _color = Color(0xFFFF0000);
      } else if ((_colorwidth / 7) * 1 < _left &&
          _left < (_colorwidth / 7) * 2) {
        _color = Color(0xFFFFFF00);
      } else if ((_colorwidth / 7) * 2 < _left &&
          _left < (_colorwidth / 7) * 3) {
        _color = Color(0xFF00FF00);
      } else if ((_colorwidth / 7) * 3 < _left &&
          _left < (_colorwidth / 7) * 4) {
        _color = Color(0xFF00FFFF);
      } else if ((_colorwidth / 7) * 4 < _left &&
          _left < (_colorwidth / 7) * 5) {
        _color = Color(0xFF0000FF);
      } else if ((_colorwidth / 7) * 5 < _left &&
          _left < (_colorwidth / 7) * 6) {
        _color = Color(0xFFFF00FF);
      } else if ((_colorwidth / 7) * 6 < _left &&
          _left < (_colorwidth / 7) * 7) {
        _color = Color(0xFFFFFFFF);
      }
      if (_top <= 0) {
        _top = 0;
      } else if (0 <= _top && _top <= _colorHeight) {
      } else if (_top > _colorHeight) {
        _top = _colorHeight;
      }
    });
  }
}

class ColorRect extends StatelessWidget {
  ColorRect({
    Key key,
    @required double colorHeight,
    @required double colorwidth,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _colorHeight = colorHeight,
        _colorwidth = colorwidth,
        _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

  final double _colorHeight;
  final double _colorwidth;
  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;
  List<Color> colorList = [
    Color(0xFFFF0000),
    Color(0xFFFFFF00),
    Color(0xFF00FF00),
    Color(0xFF00FFFF),
    Color(0xFF0000FF),
    Color(0xFFFF00FF),
    Color(0xFFFFFFFF),
  ];

  @override
  Widget build(BuildContext context) {
    return Container(
      width: _colorwidth,
      height: _colorHeight,
      child: Stack(
        children: [
          Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: colorList
                .map(
                  (e) => Container(
                    padding: EdgeInsets.symmetric(horizontal: 2),
                    height: _colorHeight,
                    width: _colorwidth / 7,
                    child: Container(
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(10),
                        color: e,
                      ),
                    ),
                  ),
                )
                .toList(),
          ),
          Container(
              child: Thumb(
                  top: _top,
                  Thumbsize: _Thumbsize,
                  left: _left,
                  color: _color)),
        ],
      ),
    );
  }
}

class Thumb extends StatelessWidget {
  const Thumb({
    Key key,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

  @override
  Widget build(BuildContext context) {
    return Positioned(
        top: _top - _Thumbsize / 2,
        left: _left - _Thumbsize / 2,
        child: GestureDetector(
            child: Container(
          child: Icon(
            Icons.circle,
            color: _color,
            size: _Thumbsize,
          ),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10),
            boxShadow: [
              BoxShadow(
                blurRadius: 0.1, //阴影范围
                spreadRadius: 0.001, //阴影浓度
                color: Colors.black, //阴影颜色
              ),
            ],
          ),
        )));
  }
}

下面是使用方法。

复制代码

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BarTypeColorPicker(
   initialColor: Colors.white, 
   colorWidth: 360,
   colorHeight: 150,
),

具体效果图：

一、RectangleColorPicker

矩形选色板的功能实现，颜色的获取是通过位置的坐标值转换为相应的颜色。这个封装好的组件可通过colorListener、onTapUpListener的回调方法，把颜色传出去。

代码如下（示例）：

复制代码

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class RectangleColorPicker extends StatefulWidget {
  final Color initialColor;
  final ValueChanged<Color> colorListener;
  final ValueChanged<Color> onTapUpListener;
  final int colorWidth;
  final int colorHeight;
  final Color color;

const RectangleColorPicker(
      {Key key,
      this.initialColor,
      this.colorListener,
      this.onTapUpListener,
      this.colorWidth,
      this.colorHeight,
      this.color})
      : super(key: key);

@override
  _RectangleColorPickerState createState() => _RectangleColorPickerState(
        colorWidth.toDouble(),
        colorHeight.toDouble(),
      );
}

class _RectangleColorPickerState extends State<RectangleColorPicker> {
  double _top = 0.0;
  double _left = 0.0;
  double _Thumbsize = 20;
  double _hue = 0.0;
  double _brightnum = 50.0;
  double lightness;
  double _colorwidth;
  double _colorHeight;

_RectangleColorPickerState(double colorwidth, double colorHeight) {
    this._colorwidth = colorwidth;
    this._colorHeight = colorHeight;
  }

Color get _color {
    return HSLColor.fromAHSL(
      1,
      _hue,
      1,
      lightness,
    ).toColor();
    //返回HSL、AHSL格式的色调亮度字符串
  }

@override
  void initState() {
    super.initState();
    HSLColor hslColor = HSLColor.fromColor(widget.initialColor);
    _left = (_colorwidth * hslColor.hue) / 360;
    _top = (_colorHeight * (hslColor.lightness - 0.5) * 200) / 100;
    this._hue = hslColor.hue;
    this.lightness = hslColor.lightness;
  }

},
        onPanEnd: (DragEndDetails detail) {
          if(widget.onTapUpListener != null){
            widget.onTapUpListener(_color);
          }
        },
        onTapUp: (TapUpDetails detail){
          if(widget.onTapUpListener != null){
            widget.onTapUpListener(_color);
          }
        },
        child: ColorRect(
            colorHeight: _colorHeight,
            colorwidth: _colorwidth,
            top: _top,
            Thumbsize: _Thumbsize,
            left: _left,
            color: _color),
      ),
    );
  }

void buildSetState(Offset localPosition, BuildContext context) {
    return setState(() {
      _left = localPosition.dx;
      _top = localPosition.dy;
      if (_left < 0) {
        _left = 0;
      } else if (0 <= _left && _left <= _colorwidth) {
        _left = _left;
        _hue = (360 * _left) / (_colorwidth);
      } else if (_left > _colorwidth) {
        _left = (_colorwidth);
        _hue = 360;
      }
      if (((5 / 360 - 5 / 360) < _left &&
              _left < (5 / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = 5 / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + 350 / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + 350 / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (1 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (2 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (2 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (2 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (3 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (3 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (3 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (4 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (4 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (4 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (5 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (5 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (5 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (6 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (6 * 350) / 6) / 360 + 5 / 360)) &&
          (_top < 5)) {
        _left = (5 + (6 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      }
      if (_top <= 0) {
        _top = 0;
        _brightnum = 50;
        lightness = _brightnum / 100;
      } else if (0 <= _top && _top <= _colorHeight) {
        _brightnum = (100 * _top) / _colorHeight / 2 + 50;
        lightness = _brightnum / 100;
      } else if (_top > _colorHeight) {
        _top = _colorHeight;
        _brightnum = 100;
        lightness = _brightnum / 100;
      }
    });
  }
}

class ColorRect extends StatelessWidget {
  const ColorRect({
    Key key,
    @required double colorHeight,
    @required double colorwidth,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _colorHeight = colorHeight,
        _colorwidth = colorwidth,
        _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

final double _colorHeight;
  final double _colorwidth;
  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

@override
  Widget build(BuildContext context) {
    return Container(
      child: Stack(
        children: [
          Container(
            child: ClipRRect(
              borderRadius: BorderRadius.circular(10),
              child: DecoratedBox(
                  child: Container(
                    height: _colorHeight,
                    width: _colorwidth,
                  ),
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.centerLeft,
                      end: Alignment.centerRight,
                      stops: [
                        0,
                        5 / 360,
                        (5 + 350 / 6) / 360,
                        (5 + (2 * 350) / 6) / 360,
                        (5 + (3 * 350) / 6) / 360,
                        (5 + (4 * 350) / 6) / 360,
                        (5 + (5 * 350) / 6) / 360,
                        (5 + (6 * 350) / 6) / 360,
                        1.0
                      ],
                      colors: [
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 255, 0),
                        Color.fromARGB(255, 0, 255, 0),
                        Color.fromARGB(255, 0, 255, 255),
                        Color.fromARGB(255, 0, 0, 255),
                        Color.fromARGB(255, 255, 0, 255),
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 0, 0),
                      ],
                    ),
                  )),
            ),
          ),
          Container(
            child: ClipRRect(
              borderRadius: BorderRadius.circular(10),
              child: DecoratedBox(
                  child: Container(
                    height: _colorHeight,
                    width: _colorwidth,
                  ),
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      colors: [
                        Color.fromARGB(0, 255, 255, 255),
                        Colors.white,
                      ],
                    ),
                  )),
            ),
          ),
          Container(
              child: Thumb(
                  top: _top,
                  Thumbsize: _Thumbsize,
                  left: _left,
                  color: _color)),
        ],
      ),
    );
  }
}

final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

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import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

class RectangleColorPicker extends StatefulWidget {
  final Color initialColor;
  final ValueChanged<Color> colorListener;
  final ValueChanged<Color> onTapUpListener;
  final int colorWidth;
  final int colorHeight;
  final Color color;

  const RectangleColorPicker(
      {Key key,
      this.initialColor,
      this.colorListener,
      this.onTapUpListener,
      this.colorWidth,
      this.colorHeight,
      this.color})
      : super(key: key);

  @override
  _RectangleColorPickerState createState() => _RectangleColorPickerState(
        colorWidth.toDouble(),
        colorHeight.toDouble(),
      );
}

class _RectangleColorPickerState extends State<RectangleColorPicker> {
  double _top = 0.0;
  double _left = 0.0;
  double _Thumbsize = 20;
  double _hue = 0.0;
  double _brightnum = 50.0;
  double lightness;
  double _colorwidth;
  double _colorHeight;

  _RectangleColorPickerState(double colorwidth, double colorHeight) {
    this._colorwidth = colorwidth;
    this._colorHeight = colorHeight;
  }

  Color get _color {
    return HSLColor.fromAHSL(
      1,
      _hue,
      1,
      lightness,
    ).toColor();
    //返回HSL、AHSL格式的色调亮度字符串
  }

  @override
  void initState() {
    super.initState();
    HSLColor hslColor = HSLColor.fromColor(widget.initialColor);
    _left = (_colorwidth * hslColor.hue) / 360;
    _top = (_colorHeight * (hslColor.lightness - 0.5) * 200) / 100;
    this._hue = hslColor.hue;
    this.lightness = hslColor.lightness;
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: GestureDetector(
        onPanStart: (DragStartDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if(widget.colorListener != null){
            widget.colorListener(_color);
          }
          
        },
        onPanDown: (DragDownDetails detail) {
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if(widget.colorListener != null){
            widget.colorListener(_color);
          }
        },
        onPanUpdate: (DragUpdateDetails detail) {
          //获取当前触摸点的局部坐标
          var localPosition = detail.localPosition;
          buildSetState(localPosition, context);
          if(widget.colorListener != null){
            widget.colorListener(_color);
          }

        },
        onPanEnd: (DragEndDetails detail) {
          if(widget.onTapUpListener != null){
            widget.onTapUpListener(_color);
          }
        },
        onTapUp: (TapUpDetails detail){
          if(widget.onTapUpListener != null){
            widget.onTapUpListener(_color);
          }
        },
        child: ColorRect(
            colorHeight: _colorHeight,
            colorwidth: _colorwidth,
            top: _top,
            Thumbsize: _Thumbsize,
            left: _left,
            color: _color),
      ),
    );
  }

  void buildSetState(Offset localPosition, BuildContext context) {
    return setState(() {
      _left = localPosition.dx;
      _top = localPosition.dy;
      if (_left < 0) {
        _left = 0;
      } else if (0 <= _left && _left <= _colorwidth) {
        _left = _left;
        _hue = (360 * _left) / (_colorwidth);
      } else if (_left > _colorwidth) {
        _left = (_colorwidth);
        _hue = 360;
      }
      if (((5 / 360 - 5 / 360) < _left &&
              _left < (5 / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = 5 / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + 350 / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + 350 / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (1 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (2 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (2 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (2 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (3 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (3 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (3 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (4 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (4 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (4 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (5 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (5 * 350) / 6) / 360 + 5 / 360) * _colorwidth) &&
          (_top < 5)) {
        _left = (5 + (5 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      } else if ((((5 + (6 * 350) / 6) / 360 - 5 / 360) * _colorwidth < _left &&
              _left < ((5 + (6 * 350) / 6) / 360 + 5 / 360)) &&
          (_top < 5)) {
        _left = (5 + (6 * 350) / 6) / 360 * _colorwidth;
        _top = 0;
      }
      if (_top <= 0) {
        _top = 0;
        _brightnum = 50;
        lightness = _brightnum / 100;
      } else if (0 <= _top && _top <= _colorHeight) {
        _brightnum = (100 * _top) / _colorHeight / 2 + 50;
        lightness = _brightnum / 100;
      } else if (_top > _colorHeight) {
        _top = _colorHeight;
        _brightnum = 100;
        lightness = _brightnum / 100;
      }
    });
  }
}

class ColorRect extends StatelessWidget {
  const ColorRect({
    Key key,
    @required double colorHeight,
    @required double colorwidth,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _colorHeight = colorHeight,
        _colorwidth = colorwidth,
        _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

  final double _colorHeight;
  final double _colorwidth;
  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Stack(
        children: [
          Container(
            child: ClipRRect(
              borderRadius: BorderRadius.circular(10),
              child: DecoratedBox(
                  child: Container(
                    height: _colorHeight,
                    width: _colorwidth,
                  ),
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.centerLeft,
                      end: Alignment.centerRight,
                      stops: [
                        0,
                        5 / 360,
                        (5 + 350 / 6) / 360,
                        (5 + (2 * 350) / 6) / 360,
                        (5 + (3 * 350) / 6) / 360,
                        (5 + (4 * 350) / 6) / 360,
                        (5 + (5 * 350) / 6) / 360,
                        (5 + (6 * 350) / 6) / 360,
                        1.0
                      ],
                      colors: [
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 255, 0),
                        Color.fromARGB(255, 0, 255, 0),
                        Color.fromARGB(255, 0, 255, 255),
                        Color.fromARGB(255, 0, 0, 255),
                        Color.fromARGB(255, 255, 0, 255),
                        Color.fromARGB(255, 255, 0, 0),
                        Color.fromARGB(255, 255, 0, 0),
                      ],
                    ),
                  )),
            ),
          ),
          Container(
            child: ClipRRect(
              borderRadius: BorderRadius.circular(10),
              child: DecoratedBox(
                  child: Container(
                    height: _colorHeight,
                    width: _colorwidth,
                  ),
                  decoration: BoxDecoration(
                    gradient: LinearGradient(
                      begin: Alignment.topCenter,
                      end: Alignment.bottomCenter,
                      colors: [
                        Color.fromARGB(0, 255, 255, 255),
                        Colors.white,
                      ],
                    ),
                  )),
            ),
          ),
          Container(
              child: Thumb(
                  top: _top,
                  Thumbsize: _Thumbsize,
                  left: _left,
                  color: _color)),
        ],
      ),
    );
  }
}

class Thumb extends StatelessWidget {
  const Thumb({
    Key key,
    @required double top,
    @required double Thumbsize,
    @required double left,
    @required Color color,
  })  : _top = top,
        _Thumbsize = Thumbsize,
        _left = left,
        _color = color,
        super(key: key);

  final double _top;
  final double _Thumbsize;
  final double _left;
  final Color _color;

  @override
  Widget build(BuildContext context) {
    return Positioned(
        top: _top - _Thumbsize / 2,
        left: _left - _Thumbsize / 2,
        child: GestureDetector(
            child: Container(
          child: Icon(
            Icons.circle,
            color: _color,
            size: _Thumbsize,
          ),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(10),
            boxShadow: [
              BoxShadow(
                blurRadius: 0.1, //阴影范围
                spreadRadius: 0.001, //阴影浓度
                color: Colors.black, //阴影颜色
              ),
            ],
          ),
        )));
  }
}

下面是使用方法。

复制代码

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RectangleColorPicker(
   [initialColor: Colors.white, 
   colorWidth: 360,
   colorHeight: 150,
   onTapUpListener: (_color) { }
   colorListener: (_color) { }
   ]
),

具体效果图：