with ChartPageState as its State.
Whenever the …ecent widget, a
StatefulWidget is not mutable, but its subtree is built by a
State object which is. Flutter retains
State objects across tree rebuilds and attaches each to their respective widget in the new tree during building. They then determine how that widget’s subtree is built. In our app,
ChartPage is a
ChartPageState as its
State. Whenever the user press…