【Flutter 学习系列 第 1 篇】在 Flutter 中如何定义obs

使用.obs 扩展更使用嘎嘎简洁，对于需要监测的对象来说，加上.obs扩展即可。

万物皆可obs

final name = ''.obs;
final isUsed = false.obs;
final num = 0.obs;
final items = [].obs;
final map = {}.obs;
//自定义类
final user = User().obs;
final items = [].obs;