超过最大文本(“")连接长度 - SwiftUI - [英] Exceeding max Text("") concatenation length - SwiftUI -

问题描述

参考 Asperi 发布的答案 (https://stackoverflow.com/users/12299030/asperi)关于问题:在 SwiftUI 中突出显示文本的特定部分

With reference to the answer posted by Asperi (https://stackoverflow.com/users/12299030/asperi) on Question: Highlight a specific part of the text in SwiftUI

我发现他的回答非常有用，但是，当我的 String 输入超过 32k 个字符时，应用程序会崩溃，所以我假设 String() 的最大值为 32k，我正在寻找解决方法.

I have found his answer quite useful, however, when my String input exceeds 32k characters the app crashes, so I am assuming the String() is a max of 32k and am looking for a work around.

在我的应用中，如果有人搜索pancake"这个词，搜索词将被存储，当用户查看详细信息页面(比如食谱)时，pancake 这个词将突出显示.一切都适用于这个答案，但是当配方超过 32k 个字符时，应用程序会因超出索引范围的消息而崩溃.(具体错误信息:Thread 1: EXC_BAD_ACCESS (code=2, address=0x16d43ffb4))

In my app, if someone searches for the word "pancake", the search word will be stored and when the user looks at the detail page (of lets say a recipe), the word pancake will highlight. All works well with this answer, but when the recipe exceeds 32k characters, the app crashes with exceeding index range messages. (specific error message: Thread 1: EXC_BAD_ACCESS (code=2, address=0x16d43ffb4))

这是该问题的答案中修改后的代码:

Here is the modified code from the answer on that question:

这将打印数据:

hilightedText(str: self.recipes.last!.recipeData!)
                        .multilineTextAlignment(.leading)
                        .font(.system(size: CGFloat( settings.fontSize )))

上面这段代码显然有更多内容，但本质上，它迭代了一个数据库，找到了最后一个包含'search word'的记录，并在此处显示recipeData，它是数据库中包含的一个大字符串.

There is obviously more to this code above, but in essence, it iterates a database, and finds the last record containing 'search word' and displays the recipeData here, which is a large string contained in the database.

实现高亮文本功能:

    func hilightedText(str: String) -> Text {
        let textToSearch = searched
        var result: Text!
        for word in str.split(separator: " ") {
            var text = Text(word)
            if word.uppercased().contains(textToSearch.uppercased()) {
                text = text.bold().foregroundColor(.yellow)
            }
            //THIS NEXT LINE has been identified as the problem:
            result = (result == nil ? text : result + Text(" ") + text)
        }
        return result
    }

我已经稍微修改了 Asperi 的答案以满足我的需要，并且一切都很好，除非我遇到了一个大小超过 32k 的 recipeData 条目，如前所述.

I've modified the answer from Asperi slightly to suit my needs and all works really well, unless I come across a recipeData entry that is larger than 32k in size, as stated before.

我尝试用其他一些数据类型替换 String ，但没有任何效果..

I have tried Replacing String with a few other data types and nothing works..

有什么想法吗?

谢谢！

更新:

在评论中经过长时间的讨论后，问题的根本原因似乎是在某些时候，对于某些记录，我超过了最大的 Text("") 连接数.

After lengthy discussion in the comments, it appears that the root cause of the issue is at some point, for some records, I am exceeding the maximum Text("") concatenations.

在上面的代码中，每个单词都被拆分、评估并添加到长字符串result"中.最终看起来像这样:Text("word") + Text(" ") + Text("Word")等等.

In the above code, each word is split out, evaluated and added to the long string "result" which winds up looking like this: Text("word") + Text(" ") + Text("Word") and so on.

这样做了，所以我可以轻松地为每个单词应用颜色属性，但似乎一旦我达到一定数量的单词(小于 32k，一个记录是 22k 并崩溃)，应用程序就会崩溃.

This is done, so I can easily apply color attributes per word, but it would seem that once I hit a certain number of words (which is less that 32k, one record was 22k and crashed), the app crashes.

Leo 建议将 https://stackoverflow.com/a/59531265/2303865 这个帖子作为替代方案，我会必须尝试实现它.

Leo suggested https://stackoverflow.com/a/59531265/2303865 this thread as an alternative and I will have to attempt to implement that instead.

谢谢..

推荐答案

嗯...意外的限制...无论如何 - 学习新的东西.

Hmm... unexpected limitation... anyway - learn something new.

好的，这里是改进的算法，应该可以消除这个限制.

Ok, here is improved algorithm, which should move that limitation far away.

使用 Xcode 12/iOS 14 测试.(还更新了参考主题 在 SwiftUI 中突出显示文本的特定部分)

Tested with Xcode 12 / iOS 14. (also updated code in referenced topic Highlight a specific part of the text in SwiftUI)

func hilightedText(str: String, searched: String) -> Text {
    guard !str.isEmpty && !searched.isEmpty else { return Text(str) }

    var result = Text("")

    var range = str.startIndex..<str.endIndex
    repeat {
        guard let found = str.range(of: searched, options: .caseInsensitive, range: range, locale: nil) else {
            result = result + Text(str[range])
            break
        }

        let prefix = str[range.lowerBound..<found.lowerBound]
        result = result + Text(prefix) + Text(str[found]).bold().foregroundColor(.yellow)

        range = found.upperBound..<str.endIndex
    } while (true)

    return result
}

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