Thank you so much! still have a question Why changing the value of [selected] will affect the synchronous change of the value of [TabbarStatus] in [vm]. And in [onTapGesture], I use [vm.tabbarStatus = tabbarItem], such method will cause xcode to crash.

Image(systemName:tabbarItem.icon) .foregroundStyle(tabbarItem == selected_item ? Color.accentColor : Color.gray) .onTapGesture { selected_item = tabbarItem//runs normally vm.tabbarStatus = tabbarItem//causing XCode to crash }