List.from 和 List.add 有什么区别 [重复]

Question

先生，我正在研究颤振。我想知道这两种代码的区别。

points = List.add(DrawingArea(
                                  point: details.localPosition,
                                  areaPaint: Paint()
                                    ..strokeCap = StrokeCap.round
                                    ..blendMode = BlendMode.clear
                                    ..color = Colors.transparent
                                    ..isAntiAlias = true
                                    ..strokeWidth = strokeWidth))

points = List.from(points)..add(DrawingArea(
                                  point: details.localPosition,
                                  areaPaint: Paint()
                                    ..strokeCap = StrokeCap.round
                                    ..blendMode = BlendMode.clear
                                    ..color = Colors.transparent
                                    ..isAntiAlias = true
                                    ..strokeWidth = strokeWidth))

Answer 1

List.add 添加单个条目，List.from 从另一个列表创建一个列表（多个条目）