How can I force the parent to rebuild? Since your parent is a Stateless Widget, you cannot change it’s color. You must use a StatefulWidget instead. Otherwise, you can use a Callback function from the child to the parent .
Read moreHow build () method works how it rebuild itself in Flutter?
There are six sets, because whenever you run the Flutter app, the setState() calls the build() method and it displays the number 0 on the screen. Next, each time you press the button, it rebuilds the descendant widget trees also. If we quit the app and restarts the app again, it starts with a fresh display of a screen.22 May 2021
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