颤振使用什么颜色系统，为什么我们使用“ const Color”而不是“ new Color”

颤振使用什么颜色系统，为什么我们使用“ const Color”而不是“ new Color”

从Flutter来源

class Color {  /// Construct a color from the lower 32 bits of an [int].  ///  /// The bits are interpreted as follows:  ///  /// * Bits 24-31 are the alpha value.  /// * Bits 16-23 are the red value.  /// * Bits 8-15 are the green value.  /// * Bits 0-7 are the blue value.  ///  /// In other words, if AA is the alpha value in hex, RR the red value in hex,  /// GG the green value in hex, and BB the blue value in hex, a color can be  /// expressed as `const Color(0xAARRGGBB)`.  ///  /// For example, to get a fully opaque orange, you would use `const  /// Color(0xFFFF9000)` (`FF` for the alpha, `FF` for the red, `90` for the  /// green, and `00` for the blue).  const Color(int value) : value = value & 0xFFFFFFFF;

const

实例被规范化。

如果您

const Color(0xFF00CCFF)

的代码中有多个实例，则只会创建一个实例。

const

实例在编译时评估。在Dart VM中，这是加载代码的时间，但是在Flutter生产中，将使用AoT编译，因此const值会带来很小的性能优势。