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 moreHow do I make widgets not rebuild in flutter?
The ultimate solution to prevent widget rebuild by flutter
Read moreHow do I rebuild a child’s widget?
A nice way to rebuild only a child widget when a value in the parent changes is to use ValueNotifier and ValueListenableBuilder . Add an instance of ValueNotifier to the parent’s state class, and wrap the widget you want to rebuild in a ValueListenableBuilder .
Read moreDoes setState rebuild widget?
When setState() is called on a State, all descendent widgets rebuild . Therefore, localize the setState() call to the part of the subtree whose UI actually needs to change.
Read moreDoes setState rebuild the entire widget tree?
If you call setState() on WidgetB it’ll rebuild itself and it’s descendants, no matter if they are Stateless or Stateful Widgets.
Read moreHow do you define setState in flutter?
Summary. setState is a way to dynamically change the UI . We call it inside the State Object class of the StatefulWidget. Calling setState marks the corresponding Widget dirty .
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