ruby-on-rails - 如何在 View Ruby中修复“NoMethodError”错误

我在卡片列表中遇到了一个问题。
我有个问题，上面写着3行问题：

.placeholder2.container.visible.card_list.row
- items.each_with_index do |cards, i|
.col-md.card-column{data: {color: cards[4].first.color, type: cards[4].first.card_class}}
  %h4
    %span{class: "icon-#{i == 4 ? ico_item : icon}"}
      = entities[i]

在日志文件中显示：

ActionView::Template::Error (undefined method `first' for nil:NilClass):

我在此模板中的完整代码：

.placeholder2.container.visible.card_list.row
- items.each_with_index do |cards, i|
.col-md.card-column{data: {color: cards[1].first.color, type: cards[1].first.card_class}}
  %h4
    %span{class: "icon-#{i == 4 ? ico_item : icon}"}
      = entities[i]
  - cards[1].each do |card|
    .col-md-12.card_line.tooltip-card{style: "padding:0px;margin:0;", data: {id: card.id, color: card.color, type: card.card_class, rarity: card.rarity, set: card.card_set, eng_title: card.eng_title&.downcase || '', title: card.title&.downcase}}
      = link_to card, class: "#{color_class(card.color)}-card-tooltip card-tooltip", target: '_blank' do
        %div.cards_gr{class: "bg1_#{color_class(card.color)}", style: "border-left: 4px solid #{rarity_color(card.rarity)};"}
          %div{:style => "padding-right: 10px;float:left;"}
            - if card.card_class == 1
              = image_tag card.hero_icon.url(:small), width: '20px', height: '20px', style: "margin-top:-4px;"
            - elsif card.card_class == 3
              %span{:style => "font-size:14px;font-weight:bold;"}= card.item_gold
            - else
              %span{:style => "font-size:14px;font-weight:bold;"}= card.manacost
          = card.title

我怎么能修好它？

最佳答案

你的问题是卡[4]为零，你必须检查它，可能会设置如下默认值：

items.each_with_index do |cards, i|
  if cards[4]
    data = { color: cards[4].first.color,type: cards[4].first.card_class }
  else
    data = { color: 'default', type: 'default' }
  end

  .col-md.card-column{data: data}

end

关于ruby-on-rails - 如何在 View Ruby中修复“NoMethodError”错误，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/53964868/