buildLeading static method

Implementation

static Widget buildLeading(
  BuildContext context,
  NavigationAppBar appBar, [
  bool imply = true,
]) {
  final ModalRoute<dynamic>? parentRoute = ModalRoute.of(context);
  final bool canPop = parentRoute?.canPop ?? false;
  late Widget widget;
  if (appBar.leading != null) {
    widget = Padding(
      padding: EdgeInsets.only(left: 12.0),
      child: appBar.leading,
    );
  } else if (appBar.automaticallyImplyLeading && imply) {
    final onPressed = canPop ? () => Navigator.maybePop(context) : null;
    widget = Align(
      alignment: Alignment.centerLeft,
      child: SizedBox(
        width: _kCompactNavigationPanelWidth,
        child: IconButton(
          icon: Icon(FluentIcons.back, size: 18.0),
          onPressed: onPressed,
          style: ButtonStyle(
            backgroundColor: ButtonState.resolveWith((states) {
              if (states.isNone || states.isDisabled)
                return Colors.transparent;
              return ButtonThemeData.uncheckedInputColor(
                FluentTheme.of(context),
                states,
              );
            }),
            foregroundColor: ButtonState.resolveWith((states) {
              if (states.isDisabled)
                return ButtonThemeData.buttonColor(
                  FluentTheme.of(context).brightness,
                  states,
                );
              return ButtonThemeData.uncheckedInputColor(
                FluentTheme.of(context),
                states,
              ).basedOnLuminance();
            }),
          ),
        ),
      ),
    );
    if (canPop)
      widget = Tooltip(
        message: FluentLocalizations.of(context).backButtonTooltip,
        child: widget,
      );
  } else {
    return SizedBox.shrink();
  }
  widget = SizedBox(width: _kCompactNavigationPanelWidth, child: widget);
  return widget;
}