Dart search, add and remove from data model List - dart

Question

you suppose this is my class as a sample code:
class SelectedPage {
final String username;
final String pageProfileImage;
SelectedPage(this.username, this.pageProfileImage);
}
in this class i want to add model data as SelectedPage when its not in _selectedPage list and when this model is in the list i should remove that from list, for example which this code is not correct
void main() {
const String pageName = 'my name';
final List<SelectedPage> pages = [];
final SelectedPage newPage =
SelectedPage(pageName, 'assets/images/my_pic.jpg');
pages.add(newPage);
if (pages.where((currentName) => currentName.username.contains(pageName)) !=
null) {
pages.remove(newPage);
print('>>>>>>>>>>>>>> REMOVED');
} else {
pages.add(newPage);
print('>>>>>>>>>>>>>> ADDED');
}
}
class SelectedPage {
final String username;
final String pageProfileImage;
SelectedPage(this.username, this.pageProfileImage);
}
i want to search 'my name' in page.selectedPages which that is SelectedPage class model data, if 'my name' exist into model i should remove that from list, otherwise that should be added to list as model

Answer 1

The way you have it will result in the object being always removed, because where() will return a List with the result for the query you've just made, even if it's an empty List.
So, if you want to do it that way, you need to query and then check if the List is empty or not. If it is, then you don't have that element, if not, then you have.
List query = pages.where((currentName) => currentName.username.contains(pageName)).toList();
if (query.isNotEmpty) {
pages.remove(newPage);
print('>>>>>>>>>>>>>> REMOVED');
} else {
pages.add(newPage);
print('>>>>>>>>>>>>>> ADDED');
}
}