Where we can use setState in Flutter?

When you change the state of a Stateful Widget , use setState() to cause a rebuild of the widget and its descendants. You don’t need to call setState() in the constructor or initState() of the widget, because build() will be run afterward anyway. Also don’t call setState() in synchronous code inside build().28 May 2021

setState is used to tell Flutter to update some state and then repaint . It should not be given any async work to do.

setState only manages the state in the widget in which it was declared — just like in React, wherein the useState hook manages local state only in the component in which it was created. This type of state management is called ephemeral state.

With reference to the state object we can say, setState() tells the Flutter framework that something has changed in this State. This change fires the build() method to rerun . Moreover, it reflects the change on the screen. The display can now reflect the change on the screen.22 May 2021