Swift 3 - 在 UITextView 中检测新行 [英] Swift 3 - Detecting new lines in UITextView

问题描述

我正在尝试在 UITextView 上计算(实时)新行，我发现下面的方法效果很好，但我实际上需要添加更多功能，但我不知道该怎么做.

I'm trying to count (real-time) new lines on UITextView, I found the below method that works well but I actually need to add more features but I don't know how to do.

func textViewDidChange(_ textView: UITextView) {
    let pos = textView.endOfDocument
    let currentRect = textView.caretRect(for: pos)
    if previousRect != CGRect.zero {
        if currentRect.origin.y > previousRect.origin.y {
            //increase the counter
            counter += 1
        }
    }
    previousRect = currentRect
}

好的，代码工作正常，但我需要:

Ok so, the code works fine, but I need to:

1. 当用户删除一行时减少计数器counter -= 1
2. 实际上这段代码在检测到新行时增加了计数器，相反，我需要在按下键盘上的返回按钮时增加计数器，让用户有可能在不增加计数器的情况下超过文本视图的框架宽度

我不知道该怎么做，您有什么建议吗?

I don't know how to do that, do you have any suggestions?

编辑(可视化示例)

这里的输出是 4

推荐答案

我自己解决了问题，如果有人需要我会在下面贴出代码(查看代码中的注释):

I solved the problem by myself, I will post the code below if someone need it (check comments in the code):

func textViewDidChange(_ textView: UITextView) {
    let pos = textView.endOfDocument
    let currentRect = textView.caretRect(for: pos)
    if previousRect != CGRect.zero {
        if currentRect.origin.y > previousRect.origin.y {
            // Array of Strings
            var currentLines = textView.text.components(separatedBy: "\n")
            // Remove Blank Strings
            currentLines = currentLines.filter{ $0 != "" }
            //increase the counter counting how many items inside the array
            counter = currentLines.count
        }
    }
    previousRect = currentRect
}

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