不同的 UITableView 部分如何在不同的 NSArray 中存储值

Question

我正在从Web服务中检索"style"和"category"的值。它们都在UITableView中分别显示。
多单元格选择选项也可用。我已经做了NSMutableArray，我希望当用户从样式部分选择一个值时，它的值进入一个数组，同样，其他部分的值进入另一个数组。当他取消选择值时，它应该从数组中删除。下面的代码没有显示任何值，无论它是否被存储。它打印的只是(null).

- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSUInteger row = [indexPath row];
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    if (cell.accessoryType == UITableViewCellAccessoryCheckmark)
    {
        if (indexPath.section==0)
        {
            cell.accessoryType = UITableViewCellAccessoryNone;
            selected[row] = NO;
            NSLog(@"indexpath zero of un-select");
        }
        else
        {
            cell.accessoryType = UITableViewCellAccessoryNone;
            selected[row] = NO;
            NSLog(@"indexpath else of un-select");
        }
    }
    else
    {
        if (indexPath.section==0)
        {
            cell.accessoryType = UITableViewCellAccessoryCheckmark;
            selected[row] = YES;
            [self.styleSelect objectAtIndex:indexPath.row];  
            NSLog(@"indexpath zero of select, %@",self.styleSelect[indexPath.row]); //this prints (null)
        }
        else
        {
            cell.accessoryType = UITableViewCellAccessoryCheckmark;
            selected[row] = YES;
            [self.categorySelect objectAtIndex:indexPath.row];
            NSLog(@"indexpath else of select, %@",self.categorySelect[indexPath.row]); //this prints (null)
        }
    }
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

Answer 1

试试这个

- (void)tableView:(UITableView *)tableView
didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
    if (cell.accessoryType == UITableViewCellAccessoryCheckmark)
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
        if (indexPath.section==0)
        {
            [styleArray removeObject:indexPath];
        }
        else
        {
            [categoryArray removeObject:indexPath];
        }
    }
    else
    {
         cell.accessoryType = UITableViewCellAccessoryCheckmark;
        if (indexPath.section==0)
        {
            [styleArray addObject:indexPath];
        }
        else
        {
            [categoryArray addObject:indexPath];
        }
    }
    [tableView deselectRowAtIndexPath:indexPath animated:YES];
}

Answer 2

如果它打印"null"，则仅表示您没有初始化数组，或者此类索引上有NSNull对象。此外，NSLog 之前的调用，即访问器调用是多余的。即应该有addObject而不是objectAtIndex，并且应该创建数组。

        if (!self.styleSelect) 
             self.styleSelect = [NSMutableArray array];
        [self.styleSelect addObject:@(indexPath.row)];   
        NSLog(@"indexpath zero of select, %@",self.styleSelect[indexPath.row]);