android - Flutter 中的 initState 和类构造函数有什么区别？

Question

我阅读了文档，但不清楚。

它声明“[initState is] 当这个对象被插入到树中时调用。”

当一个小部件被插入到树中时，就意味着它已经被创建，这意味着类构造函数被调用。初始化的目的是什么？构造函数的目的不就是初始化类实例吗？

谢谢你们的时间。

Answer 1

不同之处在于(在创建 State 对象的上下文中)它具有 initState() 方法:

• constructor simply create a new State instance

• initState() is called after the object is created and at this point you have access to the BuildContext or the StatefulWidget to which the State is attached to, respectively using the context and the widget properties. At this point the State is already mounted.

引用状态:https://api.flutter.dev/flutter/widgets/State-class.html

引用挂载状态:https://api.flutter.dev/flutter/widgets/State/mounted.html