You just need to add a field to child widget then in parent widget change value of that field and call setState() .
Read moreDoes setState rebuild?
setState() It is used to notify the framework that “data has changed”, and the widget at this build context should be rebuilt .
Read moreWhat is Statelesswidget and StatefulWidget in Flutter?
A widget is either stateful or stateless. If a widget can change—when a user interacts with it, for example—it’s stateful. A stateless widget never changes . Icon , IconButton , and Text are examples of stateless widgets.
Read moreWhat is Statelesswidget and StatefulWidget in Flutter?
A widget is either stateful or stateless. If a widget can change—when a user interacts with it, for example—it’s stateful. A stateless widget never changes . Icon , IconButton , and Text are examples of stateless widgets.
Read moreWhy are Statefulwidget and state separate classes?
There are multiple reasons : Widgets are immutable. Since the Stateful widget extends Widget it, therefore, must be immutable too. Splitting the declaration into two classes allows both the Stateful widget API to be immutable and State to be mutable .
Read moreWhy stateless is better than stateful?
The most significant distinction between stateful and stateless is that stateless do not “save” data, whereas stateful applications do . And as a result, the server doesn’t need to preserve server information or details of its sessions, whereas this needs to be done in stateful.
Read moreWhy is the build () method on state and not stateful widgets?
Why is the build method on State, and not StatefulWidget? Putting a Widget build(BuildContext context) method on State rather than putting a Widget build(BuildContext context, State state) method on StatefulWidget gives developers more flexibility when subclassing StatefulWidget .
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