NSUserDefaults将不保存多行选择

Question

I have a button that toggles from selected to unselected. When the user changes it to selected I want it to save the settings. Upon re-entry to the tableview, all previously selected buttons should still be selected, but they aren't. With my code I'm able to set one row button, but if I select multiple rows only the last one stays selected. Here's what I've tried:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

// code...

    if([cell.nameLbl.text isEqualToString:[[NSUserDefaults standardUserDefaults] objectForKey:@"name"]]){
        [cell.likeBtn setSelected:YES];
    }else{
        [cell.likeBtn setSelected:NO];
    }
}

And in the delegate method for my TableViewCell

-(void)tableViewCell:(TableViewCell *)cell {
//code...
    NSIndexPath *indexPath = [self.tableView indexPathForCell:cell];
    Car *car = self.carArray[indexPath.row];
    NSUserDefaults *userPreferences = [NSUserDefaults standardUserDefaults];
    [userPreferences setObject:car.name forKey:@"name"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

What's missing to store multiple selected rows?

Answer 1

You are replacing the value associated with the @"name" key every time. Instead, consider using an NSArray as the value, modifying it in the select and deselect delegate methods. Example:

// select
NSMutableArray *array = [NSMutableArray arrayWithArray:[userPreferences objectForKey:@"names"]];
[array addObject:car.name];
[userPreferences setObject:array forKey:@"names"];

// deselect
NSMutableArray *array = [NSMutableArray arrayWithArray:[userPreferences objectForKey:@"names"]];
[array removeObject:car.name];
[userPreferences setObject:array forKey:@"names"];