function - 如何将函数变量传递给Dart Colors

Question

我想创建一个dart函数，该函数将构建一个将播放音符的dart函数，但在函数标注中使用vars来设置键颜色。以下是我的镜头，但会产生异常:
:18:21:错误:找不到 setter/getter :'$ kcolor'。
颜色:颜色。$ kcolor，
^^^^^^^^

  FlatButton buildKey({int notenum, String kcolor, double hedgeInset, String ttitle}) {
onPressed() {playSound(notenum);}
child: Card(
  color: Colors.kcolor,
  margin: EdgeInsets.symmetric(vertical: 10.0,
      horizontal: hedgeInset),
  child: ListTile(
    title: Text(
      ttitle,
    )
  )

);

}

Answer 1

您想查找给定包含其名称的字符串的Color的静态成员。
Dart不支持。使用运行时String(或Symbol)来引用源名称是反射。您只能使用反射库dart:mirrors做到这一点，Flutter不提供该库(大多数其他Dart平台也不提供)。
如果需要将字符串转换为颜色，则需要首先构建转换表。就像是:

const colorMap = {
  "accents": Colors.accents,
  "amber": Colors.amber,
  "amberAccent": Colors.amberAccent,
  "black": Colors.black,
  "black12": Colors.black12,
  "black26": Colors.black26,
  "black38": Colors.black38,
  "black45": Colors.black45,
  "black54": Colors.black54,
  "black87": Colors.black87,
  "blue": Colors.blue,
  "blueAccent": Colors.blueAccent,
  "blueGrey": Colors.blueGrey,
  "brown": Colors.brown,
  "cyan": Colors.cyan,
  "cyanAccent": Colors.cyanAccent,
  "deepOrange": Colors.deepOrange,
  "deepOrangeAccent": Colors.deepOrangeAccent,
  "deepPurple": Colors.deepPurple,
  "deepPurpleAccent": Colors.deepPurpleAccent,
  "green": Colors.green,
  "greenAccent": Colors.greenAccent,
  "grey": Colors.grey,
  "indigo": Colors.indigo,
  "indigoAccent": Colors.indigoAccent,
  "lightBlue": Colors.lightBlue,
  "lightBlueAccent": Colors.lightBlueAccent,
  "lightGreen": Colors.lightGreen,
  "lightGreenAccent": Colors.lightGreenAccent,
  "lime": Colors.lime,
  "limeAccent": Colors.limeAccent,
  "orange": Colors.orange,
  "orangeAccent": Colors.orangeAccent,
  "pink": Colors.pink,
  "pinkAccent": Colors.pinkAccent,
  "primaries": Colors.primaries,
  "purple": Colors.purple,
  "purpleAccent": Colors.purpleAccent,
  "red": Colors.red,
  "redAccent": Colors.redAccent,
  "teal": Colors.teal,
  "tealAccent": Colors.tealAccent,
  "transparent": Colors.transparent,
  "white": Colors.white,
  "white10": Colors.white10,
  "white12": Colors.white12,
  "white24": Colors.white24,
  "white30": Colors.white30,
  "white38": Colors.white38,
  "white54": Colors.white54,
  "white60": Colors.white60,
  "white70": Colors.white70,
  "yellow": Colors.yellow,
  "yellowAccent": Colors.yellowAccent,
};

然后您可以编写:

  colorMap[kcolor]