SwiftUI-如果在ForEach循环中 [英] SwiftUI - If inside ForEach loop

问题描述

我正在基于之前获取的数组中的元素构建列表.

I am building a List based on my elements in an array I fetched before.

我正在获取所有实体.当用户在搜索栏中进行搜索时，我要过滤我的列表.我不是在做一个新的FetchRequest，我只是想过滤我的对象.

I am fetching all the entities.. when the user makes a search in the search bar, I want to filter my List. I am NOT doing a new FetchRequest, I just want to filter my objects.

这是我目前正在使用的代码:

That is the code I am using at the moment:

List(selection: $selectedDocument)
{
    ForEach(self.documentItems, id: \.self) { document in
        HStack(spacing: 0)
        {
            if (self.checkSearchString(document: document))
            {
                ListRow(document: document).tag(document)
            }
    }

我有一个列表，然后是我的ForEach循环.在该循环中，我想确定是否显示该元素.问题是，即使我不想显示该元素，列表中仍然有一个小视图.我知道为什么，这是因为我仍然渲染该HStack(). 我基本上需要将HStack()拖动到我的If内，但这对我不起作用.我认为这是因为我需要在列表中渲染一个视图.但是，如何在不渲染某些内容的情况下延续我的ForEach.

I am having a List, then my ForEach loop. In that loop, I want to decide if I show that element or not. The problem is, that even if I do not want to show the element, there is still a small view inside my List. I know why, it is because I still render that HStack(). I basically need to drag that HStack() inside my If, however that is not working for me. I think it is because I need to render a view inside my List. But how can I contiuue my ForEach without rendering something.

这是我想要实现的，但是它不起作用:

That is what I want to achieve, BUT it is not working:

 List(selection: $selectedDocument)
 {
     ForEach(self.documentItems, id: \.self) { document in
         if (self.checkSearchString(document: document))
         {
             HStack(spacing: 0)
             {
                 ListRow(document: document).tag(document)
             }
         }

提前谢谢！

推荐答案

在将数据传递给ForEach构造函数之前对其进行过滤.

filter your data BEFORE passing it to ForEach constuctor.

ForEach(self.documentItems.filter {self.checkSearchString(document: $0)}, id: \.self) { document in
    HStack(spacing: 0)
        {
            ListRow(document: document).tag(document)
        }
}

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