Flutter Riverpod StateNotifier 不添加到列表末尾

Question

im new to Riverpod and Flutter the problem i'm having is that when i use StateNotifier, the state is immutable so i have to create new state and add new value to the end of List

void add(Cart cart) {
    state = [...state, cart];
}

void inQuan(int i) {
    final tempCart = state[i];
    tempCart.quantity++;
    remove(state[i]);
    add(tempCart);
}

and this makes my list pushes the item i'm editing to the end is there any way to optimize my code?

Answer 1

This creates only one new array.

  void inQuan(int i) {
    state = [
      for (int index = 0; i < state.length; index++)
        if (i == index)
          state[i].copyWith(quantity: state[i].quantity++)
        else
          state[i]
    ];
  }