iphone - 当选择行时如何将单元格的标题保存到 NSMutableArray 中？

Question

我有一个表格，需要将所选单元格的标题保存到数组中。我的 NSMutableArray 称为 dataArray，我正在使用这一行

        [categoryItemSelected addObject: dataArray];

保存所选项目。我希望将多个项目添加到数组中 - 用户应该能够根据需要选择尽可能多或尽可能少的行。每一个都会被添加到 dataArray 中。

这是我的表 didSelectAtIndexPath: 方法

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    int index = indexPath.row; id obj = [listOfCategories objectAtIndex:index];


    //This toggles the checkmark
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];


    if (cell.accessoryType == UITableViewCellAccessoryNone)
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;

        UIImage *image = [UIImage imageNamed:@"icon-tick.png"];

        UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeCustom];

        [downloadButton setImage:image forState:UIControlStateNormal];
        [downloadButton setFrame:CGRectMake(0, 0, 19, 19)];
        [downloadButton setBackgroundColor:[UIColor clearColor]];
        [tableView cellForRowAtIndexPath:indexPath].accessoryView = downloadButton;

        cell.selectionStyle = UITableViewCellSelectionStyleNone;

        //This sets the array

    } else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;

        UIButton *downloadButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [downloadButton setTitle:@"" forState:UIControlStateNormal];
        [downloadButton setFrame:CGRectMake(0, 0, 0, 0)];
        [tableView cellForRowAtIndexPath:indexPath].accessoryView = downloadButton;

    }

    // Save text of the selected cell:
    UITableViewCell *cellSelected = [tableView cellForRowAtIndexPath:indexPath];

    if ([cellSelected.textLabel.text isEqualToString:@"Food & Drinks"]) {
        NSString *valueToSave = cellSelected.textLabel.text;
        [[NSUserDefaults standardUserDefaults]
         setObject:valueToSave forKey:@"preferenceName"];

    }

    NSString *valueToSave = cellSelected.textLabel.text;
    [[NSUserDefaults standardUserDefaults]
     setObject:valueToSave forKey:@"preferenceName"];


    NSString *savedValue = [[NSUserDefaults standardUserDefaults]
                            stringForKey:@"preferenceName"];

    NSLog(@"savedValue %@", savedValue);

    NSMutableData *data = [NSMutableData data];
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    // Customize archiver here
    [archiver encodeObject:obj forKey:@"keyForYourArrayOfNSIndexPathObjects"];
    [archiver finishEncoding];
    [[NSUserDefaults standardUserDefaults] setObject:data forKey:@"keyForYourArrayOfNSIndexPathObjects"];


    NSKeyedUnarchiver *unarchiver;
    unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:
                  [[NSUserDefaults standardUserDefaults] objectForKey:@"keyForYourArrayOfNSIndexPathObjects"]];
    // Customize unarchiver here
    categoryItemSelected = [unarchiver decodeObjectForKey:@"keyForYourArrayOfNSIndexPathObjects"];
    [unarchiver finishDecoding];
    if (categoryItemSelected == nil) {
        //If it isn't been created - then create new array

        [categoryItemSelected addObject: dataArray];

        NSLog(@"list of categories selected in dataArray %@", dataArray);

    }

    NSLog(@"list of categories selected in dataArray %@", dataArray);      

}

Answer 1

你把参数弄反了。要将此对象添加到 dataArray 中，请执行以下操作:

[dataArray addObject: categoryItemSelected];

您需要首先检查categoryItemSelected是否为nil，因为将nil对象插入到数组中会抛出异常。