preferredSize method

PreferredSize preferredSize(
  1. Size size
)

Maybe often use this when you want to make your own AppBar or NavigationBar with your custom UI

tip:the size of ios navigation bar is Size.fromHeight(44.0) kMinInteractiveDimensionCupertino, material style appBar is Size.fromHeight(56.0) kToolbarHeight,

example: appBar: Center( child: Text("hello"), ).preferredSize(Size.fromHeight(44.0)),

Implementation

PreferredSize preferredSize(Size size) {
  return PreferredSize(child: this, preferredSize: size);
}